Lead Acid / AGM vs Lithium for Off Grid Solar - Pros and Cons Part 2 of 2

[@mandelbro777]

Can't believe ppl were calling you a lead-acid fan boy. You provided some amazing info in this 2-part series and I greatly appreciate your detailed, well researched, application and user skills specific approach.

[@jamesball8519]

He is a fanboy

[@jfbeam]

Heh, he _is._ The right battery for the right job. If you're making an EV... Pb isn't the best idea. (it's been done, and made for some comical NCAP reports.) For a solar off-grid system, Pb is a very good choice, for many reasons.

[@GoldCoinBryce]

Thanks for being an engineer and not a LIPO4 sales professional.

[@jonathanwiggins7017]

Love the video!! As an EE specifically in the solar industry, the thing you are missing with lithium batteries is the quality of the B.M.S that they use. Yes anyone can just buy the same cells and stick it in a casing and sell it for cheap, but the B.M.S is where Lithium batteries shine or die. I have opened up hundreds of them as we are also a warranty center and the vast majority of failures are these boards and not the cells themselves. Plus since it is not practical to remove all the cells into a new casing, since most manufacturers seal the casing where the lid is not removable without a saw, they just go to waste. You’d also be alarmed at how many big lithium brands have incredibly cheap B.M.S or are very poorly designed to the point where it doesn’t do its job of protecting the cells properly. The best lithium battery I have come across with the best B.M.S is the Victron super pack 100ah battery. Which surprise surprise is not the one they promote as they prefer to promote the battery with an external B.M.S which is contactor based primarily in my opinion just to sell more items.

[@knurlgnar24]

Thanks for the comment and information. I did mention in the video that BMS quality is important and that most BMS's won't outlast the cells in my experience and are the weak point. I think energy storage lithium tech has a long way to go before it actually works properly for end users. We're still in the early adopter phase today and with products that are expected to last a decade or more it always takes decades for the tech to mature. We'll get there in time.

[@jonathanwiggins7017]

@@knurlgnar24 I 100% agree. My primary concern is how many of these lithium battery companies will still be around when a good majority of these fail in a few years as, like you said and as a someone who works at a warranty center for some of these bigger brands, won’t be covered by their rules leaving a lot of people out to dry. Another variable is if these B.M.S fail in a specific but not too uncommon way, a thermal event can still happen with LiFePo4 which is not good for anyone.

[@knurlgnar24]

@@jonathanwiggins7017 Well, when cars were introduced to North America there were hundreds of companies selling them. Only a handful survived. I suspect we can learn from history in that regard.

[@lubymissov]

I like it when engineers talk logically. You saved me tons of money on Li bat. Thank you very much!

[@MrDave9111]

Great job! As an engineer I was looking for some straightforward comparison information and your arguments make sense. My gut feeling what that Lithium was way oversold for stationary applications and so it is. A kilobuck for a 100 amp hour "Battle Born" battery is crazy money! I don't know how the Chinese do it yourself batteries can be had for such prices. But the risk is entirely put onto the user/builder. If you get bad cells, or they die after a year, how do you get your money back - you don't! Screw up and throw away thousands. I have been able to destroy conventional lead acid batteries via bad chargers, errors, etc. I can't imagine destroying a battery pack worth thousands because of a bad BMS component. That would be a bad day.. or maybe week! Thanks for your part 1 and 2 videos. I watched all of it.

[@nsf001-3]

I can't believe this channel still exists, I remember watching it over 10 years ago. These videos are invaluable

[@travis5833]

Hey man thanks SO much for all your work and research. This video is so extremely useful for people who want to pursue private power and wanted desperately to see through all the lithium BS.

[@jakes1292]

Good to see ya back Knurlnar24!

[@JT-lq4yd]

On video 1, I said I wanted a forklift battery for off grid storage and still do. The batteries I have seen are 8+ years old running 24/7. They get about 1.5 charge/discharge cycles per day and are still working, not at 100% as they were neglected for a long time.

[@matfurber]

One of the most informative things I have watched in a long time.

[@robertmeyer4744]

Thank you ! great info . I have been working with batteries over 40 years! which ever battery type you use you need to treat them correctly and most important thing is choose correct battery type . for camping I use AGM with carbon enriched lead type .now my off grid cabin is solar/wind and built 1996. solar and wind up graded recently . but SAME battery bank. and it's cold in NY ! still have full power on battery bank. But it a NiFe battery ! also called the Edison cell . yes you are correct about BMS is a point of failure . one thing you left out is they use mosfets and they a static sensitive . they have insertion loss that takes away from over 90% charge efficiently. because of my wife I had to keep our camping battery simple. BCI group 31 AGM in battery box. Also I have hydro caps on my NiFe and hardly need to add pure distilled water. can be used on lead acid and flooded NiCd . always remember if it can go wrong it will it's just time. Basic lead acid along with flooded NiCd, NiFe don't need BMS. there is outher types also. nickel zinc and silver zinc . don't see them anymore . I did see salt water battery buy company went bankrupt . never got data sheets or calendar ageing info . look at railroad . I seen lead acid batteries over 40 years old still working. even flooded NiCd and NiFe over 40 years old. Thank you do the research before you runout and buy battery bank !

[@knurlgnar24]

A 40 year old lead acid battery? Wow. I can easily believe 20 years - I personally usually get 10 years out of cheap car batteries in starting applications but that's impressive.

[@scruff7559]

Oasis Firefly seems to be a profoundly interesting lead battery. I have yet to try one but I hear only good things. NiFe!? Durable but 60% efficiency I've heard?

[@superciliousdude]

Excellent overview! You mentioned many points that other similar comparisons fail to mention. Thanks for making this series of videos.

[@Michael_Mears]

Really enjoyed this second part as well. I wasn't surprised that the flooded lead acid came out in front on a kWhr per dollar basis, but I've stuck with AGMs for everything: the ute (pick up), camper trailer, the 48V house system, and any other projects that come up from time to time.

[@MrSummitville]

You paid more for the Maintenance Free advantage of AGM batteries ...

[@mrhalfstep]

Good to see you doin' your thing again. I trusted you back then and still trust you now. I like hearing from a no hype kinda guy, so don't you cave in! I learn so much from you.

[@chasemoore3885]

Great research. Also, the main turn off for me on lithium battery is temperature and bms system. Temperature being the biggest set back. 2018 up in northeast winter, alot of ev was on world news for not being operational because of cold or drastically reduced range.

[@andreasheintze4891]

Thank you for the detailed video. I just upgraded my cabin solar power system with 2 x 190 AH AGMs and everyone asks why I didn't get get lithium ion. Especially after we had to lug 47 kg batteries into the boat and to the property. I did not like the notion of having a BMS in batteries because of the potential damage from voltage spikes and the fact that this is after all an electronic piece of kit. Running a Victron MPPT charger does a great job charging the batteries from 2 x 200 W solar panels, connected in series, even under overcast conditions. The system is designed to use no more then 30 % under normal operating conditions. If it would be a 4WD or Campervan lithium makes more sense due to the weight reduction and charge/discharge profile.

[@knurlgnar24]

I'm glad you found the video interesting and perhaps even useful. It sounds as though you already knew this topic in an informed manner and I likely didn't tell you much you didn't already know. I wish you well with your cabin setup, I'd love to have something similar someday though I expect life will send me in other directions.

[@leslieq958]

Your preamble is EXACTLY what I have been telling people, and why I use flooded batteries. I use the saved money for the vacations in my RV.

[@knurlgnar24]

Trouble is, good luck finding an RV at a reasonable price today!

[@rogerkaday3973]

Happy to see you back. Love your videos, sure did miss them while you were gone

[@tombair1]

Excellent talk and it does temper my love of lithium. However I have a full-time RV application and weight is important. Also constant worry about shading and getting to full charge with AGM was always a problem. The BMS is a source of failure but it also keeps the battery from falling victim to so many of the things that kill batteries. Finally, the ability of the lithium to take everything my solar panels give them until effectively full is great when you have a narrow charge window due to shading and probably the biggest advantage. I will confess I killed a set of off brand AGM batteries after 3 years of full time use, I tried to keep them above 50% SOC (I don't worry with the battleborns) so with battleborns even if they die of old age at 8-10 years I will be ahead cost wise and quality of experience is not even comparable due to lack of worry about charge states. This might be different if I knew what killed the AGMs but I don't --good MS charge controller set to manf. settings with low DOD, who knows. I would venture to guess, that most people do not get full life out of lead batteries due to either ignorance and/or the narrow conditions that must be met to get "full" life that are not compatable with real life. Just my $0.02. Again loved the talk and you make very good points particularly for a fixed bank, just thought I would throw out some other considerations.

[@knurlgnar24]

I agree with everything you said, and I think in your application you made a good battery choice.

[@brucebear1]

I hear you. I found that there was no way to keep a battery pack for a very limited house electrical system on my RV charged with solar, plus I had to run my generator for any air conditioning anyway. I consider my solar system as a minor addition to my "main" power production system. Plus, I paid $120 for a surplus cell-tower array (10 78Ahr 12V AGM batteries, "timed out" at 4 years. In five years of my service, one of them failed to hold a charge so I'm down to 502 Ahr capacity (the other nine test out to over 95% efficient versus new). If I can get another three years out of this array, I'll have a yearly battery cost of $15. I'm going to go out and buy $9600 of Lithium batteries in three years? Oh, yeah, sure! And when the solar panels age out, I'm out of the solar business -- not worth it for me. The noisemaker and the $108 dollars worth of batteries mean that my wife never has to not run something she wants to but we only have to run the generator when it's "socially conscious". We're happy.

[@jackiemuenz4152]

Cant wait to hear about your 15kwh litihum pack . Please let us know. Anything solar oriented very interesting. Glad someone takes the time to do this.

[@JohnSmith-qd8po]

Any progress on the lithium battery ? I think that you will be impressed with the performance. I am with mine.

[@joepah51]

Welcome back! Agree that Lithium batteries suffer degradation irrelevant of use... Had two battery packs on my Ultramotor electric bike.. One pack was used all the time, the other maybe once every two weeks. HOwever a quality warrantee is worth its weight in gold for an ebike! After 4 years both had the same bike range.

[@nowanda2nd]

I love this video series and learned a lot about lead acid batteries. I used to compare sealed lead acid batteries in small UPSs I had with Li ion and concluded that lead acid batteries don't last long. It would be great if you could do more videos on proper lead acid (flooded, gel, etc) maintenance and use.

[@knurlgnar24]

UPSs are hard on batteries. For market reasons they want you to replace the batteries every few years.

[@matthewwakeling4978]

Yeah, and my UPS, the manufacturer tried its utmost to stop me changing the battery on it at all. They want to kill the battery and get you to buy a whole new unit.

[@johncraig406]

Very good job of telling it like it is. Maintenance and proper use and proper use for the battery type, is the critical factors

[@phazephusion]

Your scientific approach to comparing the technologies has been extremely helpful and have opened my eyes. I will definitely be looking at the AGM batteries for my solar setup here in sunny South Africa. Thank you very much

[@knurlgnar24]

Glad the video helped! In a hot climate please pay special attention to the battery bank temperature. You may find it less expensive to spend more on cooling your battery box vs the accelerated degradation and replacement cost of batteries. e.g. install them in an earthen/concrete pit or basement to help them stay cooler or other such measure appropriate to your situation.

[@phazephusion]

@@knurlgnar24 That's a good point you're making. I have a given it a bit of thought since I previously planned on going the LiFePo route. My garage has the most stable temperature throughout the year. It's always between 10 and 25°C even when the outside temps drop to 0 (once a year) or rises to 35°C or more (most of summer). I'm planning to build a sealed temperature controlled (with fans) wall mounted cabinet. That's actually one of the important things people don't do when they think of going off-grid: Scientific research (and comparison) to plan for the long term. It's one thing to use an online calculator and another thing to plan out where what should go for the healthiest system that will be the best for a long-term investment.

[@phazephusion]

@@knurlgnar24 The biggest point that won me over to Lead Acid was the maturity and proven track record of the tech. With Liquid Metal Batteries on the horizontal for consumer applications, LiFePo tech may never get the chance of reaching the maturity of Lead Acid in solar applications. The recyclability of Lead Acid batteries is also a big win in my book.

[@cornoadmin]

Thank you for such a rational discussion on the subject. I really appreciate it. Oh, and welcome back!

[@aatirehrarsiddiqui8894]

This is technical gold. Subbed.

[@MStrickkk]

Not having to worry about undercharging lithium is the main reason people "love" them (besides all the marketing from sponsored KZbinrs of course) and the ONLY reason I consider lithium for big power. For small mobile packs (think external flash light power, RPi power etc) of course the weight is the main plus.

[@knurlgnar24]

Lithium has significant advantages. It also has disadvantages that people choose to ignore.

[@TRYtoHELPyou]

My Tesla model s charges to about 222 miles at 90% charge... Next month is it's 8 year birthday. Panasonic and Tesla definitely have their poop in a group. LFP will probably be super sweet for longevity. I like your videos dude. Trying to refresh a riding Ryobi mower I got for 300 bucks off Craigslist.

[@TRYtoHELPyou]

Oh dang. So I got a laptop from the thrift shop the other day. Battery still works well and it's over 20 years old.

[@peterthomas6566]

Thank you for a very informative and unbiased presentation! I live in the warmer climate of Crete, Greece and my near off grid system has evolved over the last three years or so, as grid supplied electricity prices have increased, I have increased the capacity of my system to replace more of the grid energy. Here in Crete electricity prices try to encourage at least energy economy, the first 300 units per month are still extremely cheap, around $0.05 per unit (with a lot of that energy being generated by a mix of wind and solar at regional generator level), so hard to justify trying to replace those units with self generated electricity, but from that point onwards the unit price increses a lot, with my local property tax also being based on the quantity of electricity I consume, increasing fairly dramatically as well. I did a lot of research and in the end opted for lithium LFP batteries made by Pylontech. I have no space or weight restrictions and the temperature seldom drops below 10 Centigrade, with highs of around 38 -41 Centigrade. What comes across clearly from your presentation is the fact that when I was deciding what storage to use is that the information on lead acid technology is absolutely solid, whereas so much of the lithium information appears to be more marketing than science, even when looking at the spec sheets. I'm 70 now so it's unlikely that I'll become aware of whether I've made a serious mistake in choosing LFPs. If as seems likely those LFPs are going to die much sooner than I expected, then lead acids will be the replacement, fortunately my charger/inverters can be configured for either type of battery, assuming of course that the failing LFPs don't destroy the whole system! The points about recycling are well made, I'm slightly more optimistic on the basis that as more and more lithium batteries reach end of life, someone will find a way to recycle them driven by the good old profit motive. What bothers me most is the fact that the world seems to be jumping blindly onto the lithium route based on not much more than marketing hype! Most politicians, what ever their ideological persuasion always look for a "One size fits all" solution, but of course the reality is that that is not possible. For cell phones & laptops lithium is a no brainer, for EVs (If that is the right route?) probably a no brainer too, but for domestic based storage it looks like a very expensive dead end, that, despite my engineering background, I've bought into and used far more of my savings to gain independence from the grid 🙂 Lithium tech is advancing rapidly, but from your presentation it looks like it has much, much further to go before it becomes the storage solution of choice. As a cosequence of all this, is there a way to use both lead acid and lithium technologies in the same installation?

[@knurlgnar24]

You sound knowledgeable and experienced. Thank you for adding your words of wisdom. I suspect by the time your LFP batteries need replacing there will be better (or simply less expensive lithium based) battery tech to replace them. We can only live in the now, not the past or future. I've also considered ways to use both lead acid and lithium in an integrated system and I haven't been able to come up with a good way to integrate them into a single energy storage solution that allows for effective use and lifetime of both technologies. My best solution right now is to keep them separate with some sort of bridge system inbetween to maintain balance. Your comments on recycling lithium batteries is interesting and I hope you're right. The main issue today is that manufacturing process costs are high while raw material costs are relatively low. I hope that balance will change but until it does recycling will remain a problem. One can't just dump lithium batteries into a shredder then melt them to burn off the plastic and skim off the dross like they do lead acid batteries.

[@chrishammond5001]

So glad you are making videos again.

[@RicardoCerveraBlanco]

Thanks for the video, you made a lot of sense in the whole plot... I am looking into building an off grid house in spain and don't understand the fascination over lithium, even if you kill a lead acid battery you can always drain it, clean it and refill it, if you know what you doing it should be good again... Something you don't mention in the video is the crank power the battery can deliver, lead acid puts out the highest current and binger batteries for example truck batteries 48v are monsters that can take almost anything. Regarding the DIY battery, well, it doesn't work at all, people don't take in consideration their hourly rate on a diy system and the time it takes for it to get done, plus every little count, not getting the right cable or buying a thicker cable will increase the cost of it, getting a thinner one and you can risk something going wrong, then is the over thinking, should i fuse each cell, what bms to use, what if is not enough then i will have to do it all again or just tear everything out and make 1 bigger... I have unlimited supply of 36v battery packs for ebikes and i been building a test pack to see if it worth it and honestly, it doesn't... Main issue i have come across is that the cells and packs has a mind of their own, I have a thermal camera and i check them when charging and when under a load and there is always a randome cell or pack that gets hotter and i truelly believe is due to the crank power the the cells or the bms can deliver, when using a acid battery, the can give some much amperage in one go that the flow of current is smooth in both charge and discharge, this variation of temperature are worrying with lithium, all it takes is 1 cell to give in or catch fire and it will be unstopable... I gonna set my system with lead acid batteries for the most basic reason that you explain, if my comsumtion is too high for the battery bank, i just buy more batteries until I reach 30% discharge mark and that will made sure it last me at least 10 years... Again, Thanks for the video...

[@knurlgnar24]

I think there are some very good reasons to consider LFP batteries for off-grid solar, but I do NOT consider cylindrical batteries a viable solution and suspect they will never be. Prismatic cells will likely be the future for this application yet I have no idea exactly when the transition/choice will be clear. As of today lead acid is the better choice for most stationary applications in my opinion and for the reasons stated in this video series. LiFePO4 patents start expiring this year (2022) so it will be interesting how things develop over the next 5 years or so.

[@RicardoCerveraBlanco]

@@knurlgnar24 I think maybe as you, that is always best to keep things simple and as you mention in the videos and in the reply, hopefully companies are working in batteries for this specific usage like pylontech and keeping an eye on what mobile phone network are using as their network ups as they are super complex systems, they self test blackout to make sure the ups response is fast enough to keep the network running and I'm not 100% sure but i think now with the 5G network is when they are integrating lithium batteries for the ups... Again, Thanks for you video...

[@brianhawki7149]

Great video ! and i repeat nice to see you back making videos again sharing your knowledge, what a hot topic too on this video but you prove lead is far from dead and still your best battery option for an off grid system. Thanks !

[@NaughtyGoatFarm]

I have really enjoyed your series from 8 years ago on the battery backup system. I have managed to get 20 x 75ah 12v SLA batteries that are only about a year old and seem to be testing out OK. Picked them up for scrap value. And I'm likely to be able to get more of the same cells from this supplier over time. So I'm looking at putting them together to run an off grid system for my garage.

[@knurlgnar24]

It sounds like you have a nice 'in' with a good source. Those batteries may not meet the requirements for a high reliability commercial application anymore but that doesn't mean they won't make a great off grid system for someone who knows what they are doing. Congrats! I am surprised how many views those old videos still get. If you haven't seen it I have a newer video on desulfating using a lab style power supply. It may be more relevant today.

[@theursulus]

Well said! I've always thought, from the literature I've read, that lead acid battery storage for solar is better than lithium on price point But you do need to look after the lead acid..

[@knurlgnar24]

I look forward to the days when lithium overcomes lead acid since tech such as Lithium Iron Phosphate should be very inexpensive in the future due to the low cost of materials. Processing is the majority of the cost today - I have to think they can figure out a way to get that down in high volume. Lead acid will live on for a very long time though for certain applications such as engine starting applications.

[@Arta-nd7wf]

Hello there again Knurlgnar I just thought I’d give you some video ideas for the near or perhaps non existent future of this great KZbin channel. 1 How to store and maintain lead acid batteries. 2 An update video of Your 1000 AH battery bank along with the 12v generator. 3 How to clean electronics/circuit boards. 4 Some more inverter reviews and tear downs. I hope you take note of these ideas and I hope you’re ok and doing well. Cya

[@juniorfolkes-u2g]

Very good information

[@superblondmale]

I like your approach to the topic and I am very interested in a holistic view of the problem. It's much needed! You calculated the expected lifetime on DOD which I think is to coarse to reflect the beneficial properties of lithium batteries. E.g. a lithium can be discharge deeper and don't have to be fully recharged every nth day. In a real world application where you use solar to recharged your batteries this may safe you from using any grid energy. Thus making the usability of lithium batteries greater. Also they don't suffer that much by staying some time at a lower charge (

[@tonyford666]

DOD is what the whole exercise is about. Lead acid doesnt have to be fully charged all the time to work, just for storage. And can be charged down and dirty with minimal equipment which makes them more robust and reliable. Heck you can even charge directly from a solar panel or your vehicle in case of emergecy if your controller goes bad and you dont have a spare. Try that with llpo and see how fast you let out the smoke. Thats a grearer benefit for me where I live in the hurricane belt.

[@jws3925]

This series is very interesting and I can't wait for the rebuttal from the Lithium Iron Phosphate crowd. Unless I am mistaken or misinformed, no one can definitively present data on Lithium battery chemistry longevity because it just hasn't been around long enough to do so. Predictions of longevity at this time are just that, predictions and likely will not prove to be confirmed as time goes by. Furthermore, the variations of Lithium chemistries are evolving at an amazing rate. Right now Lithium Iron Phosphate appears to be the safest and most popular chemistry out there but I would not be a bit surprised if a new chemistry comes along in 3-5 years and Lithium Iron Phosphate is mostly ignored. We have seen this already in regard to battery technology. One thing you mentioned here that kind of raised my eyebrows was that AGM batteries should be equalized on a regular basis. I have Trojan AGM batteries (T-105-AGM) in my solar system and the manufacturer does not recommend equalization. So, I am confused on this issue. Care to comment? Lastly, I was intrigued with the North Star battery and did more of an online research into them. It does not seem to be widely used in the solar world and I am wondering why. Also, there appears to be limited distributors and shipping is pretty expensive. I am not looking for a whole pallet of batteries just a few and in that scenario to my destination the distributors I contacted wanted a couple hundred dollars freight shipped. Do you know where I can purchase these batteries in either MI, FL or PA for pickup? I could not find any.

[@knurlgnar24]

@@lexiecrewther7038 Lexie, I'm curious why you are so rabidly supportive of LiFePO4? Is it related to your job or investments? I have not yet seen data proving longevity of today's LiFePO4 cells in the application covered in this video. Could you point me to some of it?

[@carlosestrada6922]

Good to hear i feel the same way about lithium my lithium battery failed in drills every year so I have not change to lithium till I see better results. I'll stay with AGM i have 800 ah at 48 volt and it has no problem it runs 24 7 thanks for this 2 part video

[@briangroene7756]

Damn great info here. Makes me rethink using the higher quality agm batteries

[@cdtrotors8405]

Awesome video, painfully long, but awesome!

[@turboturd7954]

If your circuit can't handle the fact load, increase your breaker rating :)

[@geworthomd]

Thank you for taking the time to answer my questions. Great information. You are a good resource.

[@PeterLawton]

Speaking of Kia, I took mine to the dealer (Ft. Wayne, IN) for service. They took a photo of "sludge" where oil is added, and recommended replacing the whole engine, which was running just fine. LOL!

[@richardhobbs9038]

If you took it to 'Sarah -n- Tuned' that "sludge" would disappear AND it would be running perfect ! !

[@durangarc]

I had a lead bank to power my home in an off grid system for 5 years, then switched to lithium. I will NEVER go back to lead. In fact, I've never heard of someone going back to lead, and I'm in many forums and communities.

[@knurlgnar24]

This video is about what does more work for the money spent over time, not which is nicer overall. You bought a luxury SUV to go to the grocery store. Nothing wrong with that, but you can do that same job for less with a Kia Forte.

[@durangarc]

@@knurlgnar24 I don't think so. I bought fairly new NMC batteries for about $100/ Kwh and with more EV cars being decommissioned, the prices are decreasing. With lead, I needed so many more lead batteries to do the same job because of the voltage drop and the small range of discharge. The consensus in the diy community is to move to lithium.

[@scruff7559]

I never left/went back to lead. I use both and I know how to keep lead from sulphating. On a cost per kWh where I don't have to lift them Lead is King.

[@garbleduser]

My modded APC smart UPS is still running like a champ. Let me know if I can mail you some even better matched mosfets for another upgrade.

[@butchclifford8733]

Great to see you on KZbin again Knurlgar, I've watched this two part multiple times and I do not understand your recommendation that AGM batteries need to be equalized once every 30 days, it has always been my understanding that this would boil and dissipate the fluid in the AGM thereby ruining the battery, could you comment please, waiting for your 15Kw Alibaba video!

[@knurlgnar24]

Some manufacturers recommend regular equalization of AGM batteries and some specifically forbid it. It depends on many factors including battery construction and end use parameters. Also note that 'equalization' in this context simply means a higher voltage than recommended for a standard charge. You wouldn't want to equalize an AGM battery with the same procedure as a flooded battery except in special circumstances. People who have worked with batteries know that if you contact technical support for sulfated AGM batteries the manufacturer will likely recommend a desulfation process of cycling and equalization to restore the battery even though their published literature specifically forbids it. In general I believe it is rare where an AGM battery in an off grid solar setup will survive its full life without needing equalization and I have seen many people complain about battery performance which I can immediately recognize as simple sulfation due to undercharging. In short my recommendation is: Only equalize AGM batteries when necessary. This depends on your battery, your charge setup, your use scenario, and your data showing conductance changes, capacity loss, or other such information which indicates damage. The battery bank should be equalized BEFORE this damage occurs and when it does occur depends on a multitude of factors. The manufacturer of the AGM battery in this video does recommend equalization in certain use scenarios, and I agree with that recommendation due to real life not being ideal.

[@knurlgnar24]

A second comment here to clarify: Every battery chemistry/construction has a specific voltage where outgassing will start to occur. Below this almost no water is used but plate corrosion and shedding still do occur. Equalization in an AGM battery is typically only slightly above this critical voltage point so that outgassing is minimal and only the plate corrosion/shedding issue is accelerated. AGM tech is very good at recombining a significant portion of the H2 and O disassociation so even though the chemistry and math dictate that you lose about 1ml of water per 3Ah of overcharge the real water loss is far less than the math and chemistry would indicate.

[@DennisWintjes2]

Thanks!! Again, welcome back! Please keep making videos! Like #350. Regarding the comment of application, i think this is a key point. If you are mobile and moving in an RV, weight/size matter, in a buisness where the batteries will never move, and you can have an employee perform actions on a schedule, lead wins.

[@jaredharvey1511]

Did you get 10 years out of that flooded acid bank? Looks like you initially got those about 10 years ago.

[@knurlgnar24]

They're still working well. Not 100% but working well.

[@jaredharvey1511]

@@knurlgnar24 would you have a recommendation on a battery for a home application today? I'm planning for around 15kwh 48v with EG4 or similar hybrid Ingrid / off-grid inverter. I'm not scared of vent maintenance or keeping them temperature regulated. I'm thinking flooded lead acid. I'd kind of like an option which allows me to diy recycle the battery. Lead can be reclaimed / purified with electrolysis. Then recast using an RTV mold. By reclaiming the lead I could reduce long term costs. However I don't know if any options like this so for now probably just buy something off the shelf. I'm thinking build a shed with "basement" away from the house. Put batteries at least a foot below grade with insulation on top of them as a subfloor. Frost code in this area of Maine is 4ft, but I've dug into the ground in February and frost wasn't even a foot thick. So I'm thinking a foot or more would be sufficient. Warm in winter time, cold summer time. Then shed will contain electronics and a backup generator. I'm an electro-mechanical engineer by trade and degree.

[@knurlgnar24]

@@jaredharvey1511 Take a look at my video on lead acid vs lithium. It's a two part video and one of the most recent if you look at my channel history. You sound like me in terms of how you think. I live in an area of the USA where the frost depth is a little over 4ft and frost DOES get to 4ft some years. Other years it doesn't get more than a few inches. There are websites that have historical data on frost depth you can look into. My water main (5ft depth) got to 34F one cold winter when there was little snow cover. I suggest going with what the IBC says or plan for some sort of backup solution. Self heating will likely be enough though for your case. My reason for not doing anything below ground is humidity. Humidity will absolutely destroy electronics and battery connections. Personally I'd opt for something well insulated above ground. Lead acid batteries are very complex to manufacture. Simple casting won't make a viable battery, though perhaps you could use the pure lead for some other purpose. You'll need to purchase a commercially made product to get a battery that's worthwhile.

[@jaredharvey1511]

​@@knurlgnar24Do you know why elevated temps decrease the life? Is that a chemistry issue? Does it errode plates quicker? What are the reasons why it fails at elevated temperatures? How does the calcium based alloy plates reduce the outgassing? Does the calcium react with the gas to prevent it from being a gas?

[@colscopters]

I've a question I've got a boat that runs on a all electric engine it uses lead acid battery I use the boat all day until the battery is dead this battery is its main power for propulsion iam I killing off the battery running it flat all the time if so anyway around it thanks great video

[@knurlgnar24]

For practical reasons I'd say what you're doing is fine despite the advice you'll find elsewhere. In general you'd get a little over twice the cycle count life if you only used it down to 50%, or if you used the same amount of energy but had two batteries in parallel. Of course two batteries costs twice as much as one battery so in the end what you're doing is reasonable given that weight and space are important on a boat. The most important thing is to immediately charge the dead battery when you get to shore. Even a day at zero charge (each cycle) will quickly damage the battery. If you have the space - and I'm assuming you don't - more battery would be a good thing for quality-of-life reasons more than anything else. e.g. Personally I get uncomfortable when my gas tank is down to 1/4 or my phone battery is low.

[@colscopters]

Many thanks ive two batteries and I recharge them as soon as I get to shore I was thinking about lithium battery but now after watching your videos I think iam just going to stay on my calcium flooded batteries as they serve me well and are cheap thanks again for your help ive subscribed as you are very helpful thanks

[@MrClipper500]

Not sure if you are an electrical engineer but a good topic would be why Grounds and Neutrals are bonded at the first disconnect switch but not at the sub panels. Also, I am considering an inverter and battery pack in lieu of a backup generator. In some of your videos the ground terminals are not connected to the outlets on many inverters. With a push pull inverter that does not use a ground are these inverters safe for home backup? I would be concerned with the inverter powering the neutral in the box and putting the person on the pole in danger. Worse, if inverter generators are wired in the same way could using them for backup power and plugging them into a transfer switch be unsafe? I would think that the inverter neutrals/grounds would have to be isolated along with the mains as well. Good topics for future videos. Keep the vids coming.

[@tekdragon]

I never realized that occasional overcharge on AGMs is significantly less damaging than occasional UNDERcharge. I guess when in doubt, put a charger on it! thanks alot for all the time you put into making this video. I always learn something new from them. You ever think of creating a forum/reddit/Discord or something for us all to chat about batteries and inverters and such?

[@knurlgnar24]

To be clear I'm not saying that overcharging AGM batteries is a good idea or OK, just that being overly worried about overcharging can be detrimental to their lifespan. I'm not much for social media but that's an idea I could consider - there is a lot of knowledge out there and we could all learn from eachother. An interesting thing about negative comments on videos like this is that I know I make mistakes and that not everything in these videos is 100% correct, yet for some reason people rarely point those legitimate errors out and instead focus on other aspects of the videos. KZbin commenters are either an odd bunch or a good reflection of social behavior on some level I'll never adequately understand.

[@scruff7559]

The quickest route to the truth is to say the wrong thing. Overcharge is waaay better for lead than under. The paranioa of overcharge in the market has compromised most of the chargers on the market. I run every charger I have on flooded batteries and hydrometer test until I know the settings are right and the charger is capable before I use that charger on AGM. It takes >2weeks (with solar, days with mains) to overcharge lead it's so ineffient at the top of it's SOC. I speak of overcharge not to be confused with over-voltage. Lead has a non-linear efficiency, it bell curves. Operationally with conventional chargers it is ~95% efficient. If you want to go all the way to 100% it's hard work and the efficiency dives. I gather that's where the 80% round trip thing originated but most people can't/don't operate lead this way. My findings have been that as long as the battery sees 1.28 SG once a month then it's tolerant of unmitigated abuse and lasts indefinately (haven't killed one yet).

[@MrSummitville]

@@scruff7559 Chronic overcharging is LESS WORSE than chronic under-charging, not "way better" ...

[@scruff7559]

You believe forming irreversible hard crystals from your active material is better than some water loss that's replaceable? Do you understand how difficult it is to charge a battery to 1.28 specific gravity? Have you any evidence to back up your statement? Have you looked at the efficiency curve of a lead acid battery and how it bell tapers from 100% at 80% SOC to 0% at 100% SOC making overcharge almost impossible? How often do you replace your lead acid batteries? I've never had to replace mine some are over 10 years old.

[@gravelydon7072]

Short circuiting Lead-acid batteries can result in battery explosions which are far more violent than the Lithium batteries catching fire. Each cell in my LiPo batteries has its own BMS circuit so a short on the output only does one thing, a very brief spark. The BMS limits what it allows out and you cannot get over the rated Amperage out. Now what can the battery itself put out without the BMS, I don't know. But it will melt the connection strips if shorted.

[@knurlgnar24]

BMSs use FETs to protect against overcurrent. Do you know the most common failure mode of a FET? (shorted) And do you know the most common cause of FET failures? (EOS such as caused by excessive currents resulting in inductive kick) I have designed power electronics for industry and you absolutely need a fuse on a lithium battery as BMSs are failure prone. DO NOT rely on them for battery overcurrent protection. Lead acid batteries won't explode if shorted unless they are low on water or in very poor condition. They will vent a lot and perhaps spray acid out of the vents though.

[@gravelydon7072]

@@knurlgnar24 As someone with decades ( half century actually ) of experience with Lead-acid batteries ( including ones that weigh about a ton ), I can tell you for a fact that they will explode even when they have the proper amount of water in them. It just takes a big enough short. And yes, I do protect the Lithium batteries with circuit breakers or fuses. But it still is a BMS that does most of the work.

[@scruff7559]

raw li-ion cells have no BMS. They're far less tolerant of a S/C and more volatile. Apples to apples gents!

[@gravelydon7072]

@@scruff7559 The way I get them, each 2 cell pack has their own BMS. The BMS is a dual unit. That means that each cell has its own circuit. New, they run about $10-15 each. As I charge them only at 28.8 Volts, they always stay below the 29.4 that they could run to. The BMSes actually cut them off at about 28.7 when in a 7S configuration of twin cells.

[@scruff7559]

The way I get them is a brick with terminals. I make the BMS. I tire of people comparing Li-ion to lead when they are actually comparing a raw system to an electronically protected one. Lead + BMS vs Li-Ion + BMS or raw lead vs raw li-ion...this is apples to apples.

[@junkerjason7637]

Thank you for all the great info, im new to solar (2 months new) I'm just playing around with habor frieght solar and walmart batteries, i didn't want to invest a lot into something I needed right away(to charge power tool batteries, phones, run a fan etc.)but knew next to nothing about. Im just using 300 watts solar and 3 114 ah 12v batteries. Im learning i need more solar to hit that full charge which im having a hard time doing. Anyways im just learning with cheap stuff before i start investing serious money, i was thinking lithium before i watched the series now im thinking back to my original thought that good old lead is right for my application. Thank you for making these videos, lots of great information that made sense to even a newbie like me.

[@knurlgnar24]

Glad I was able to help! Yes, it is best to start with exactly what you are working with - lead acid and harbor freight style equipment. It is so easy to destroy expensive batteries be it lithium or lead acid so the way you are doing it is very smart. Lithium has great advantages and is the technology of the future but it isn't all unicorns and rainbows. For many situations lead acid still has a place even in high-end large scale applications. In your case lower cost lead acid is a great technology and once the 5 year or so life is spent you can move on to whatever system you then choose.

[@panoss3524]

Thanks for your video it was very useful! I had 48v agm 650ah 2v x 24 system about 8 years. I abused my batteries with temperature and overcharging many times. Now i will buy lead acid batteries because i can do something to fix them and increase time.

[@knurlgnar24]

And you still got 8 years out of them. Not bad! Which battery model did you have?

[@gene8135]

The point made at the 38:38 timestamp (power output) goes against what you've said several times throughout both videos: it's not a problem with the battery, you're not using it correctly. The focus of these videos is on the use for off grid solar installations, which will have an array of batteries and be able to provide the higher amperage needed for jumping a car. Even with an RV installation, which would have only a few or even one battery, I doubt one would expect to use the batteries this way. There are much smaller, purpose built tools and batteries for jumping cars. I doubt anyone would want to rip their battery out of their RV installation to jump start the vehicle.

[@knurlgnar24]

I'm not sure what your point is. The power output of a lead acid battery is significantly greater than that of a lithium battery with a BMS, which I view as a necessary component. That is a fact.

[@gene8135]

@@knurlgnar24 You have stated in both of your videos that 1) Failures with lead batteries can usually be attributed to improper use (e.g. selecting golf cart batteries to use for an off grid installation) and 2) That viewers need to keep the context of the videos in mind when bring up points to debate, that these videos are about off grid power storage installations. Pros/cons for other uses don't apply here. Following both of those points, being able to use a lead battery to jumpstart an engine should not have been listed as a pro. 1) the lithium battery you used for comparison wasn't designed to jump start cars and 2). Jump starting a car doesn't apply to the scenario the comparison is being made in. Besides, no one shouldn't be removing a battery from their off grid installation to jump start their car. There are safer, easier and far less expensive tools to accomplish this.

[@gene8135]

Bear in mind, I'm not dismissing the whole comparison, I'm not attempting to invalidate all of your points by singling out a single problem in what you presented. Just pointing out that it shouldn't have been included as a Pro/Con.

[@knurlgnar24]

@@gene8135 The statement regarding starting a car was intended as a reductio ad absurdum. You're right in that my statement taken at face value is ridiculous and not a valid argument - and that was intended. Lithium battery manufacturers often tout things like 'output power' that are outright false and I believe it is important to call them out on these false claims. I think I understand what you are saying now and I believe the disagreement is a result of miscommunication on my part.

[@johntuinenga8197]

I installed an Aims 12KW inverter system with their panels, charge controller and AGM batteries. After four months the batteries are reading replace on my battery tester and also the local solar contractors who set up a 14KW Kohler backup generator. I'm looking at fighting with the Inverter store to replace the defective batteries. If I'm no successful what would you recommend to get the most bang for my buck. Your videos are very good and some times over my chemist degree head. LOL It's a daunting task to try and figure out what to do. If I talked to four different solar companies I'd get four different answers depending on what company they represent.

[@knurlgnar24]

I suspect your batteries are still good and were undercharged. I have a few videos about desulfating batteries you could try watching if you're interested. I think you can likely restore them to good condition. With lead acid batteries it is difficult to set up a system that doesn't damage them due to undercharge which is what happens to most people who use them. This is a significant advantage to lithium as they don't need to be fully charged each day to maintain battery health. I don't know your situation so I could be wrong in the above. Right now in today's market lithium batteries are rapidly increasing in price so you may be stuck with lead acid for a while until lithium prices come back down since lead prices are staying stable. If you do get new lead acid batteries I highly recommend getting a lead-carbon battery. Leoch, Trojan, and Northstar are the 3 major manufacturers I am aware of that have applicable batteries of that technology. These can better handle undercharge conditions.

[@johntuinenga8197]

@@knurlgnar24 I have watched your videos on desulfating batteries. I remembered seeing something in the Aims inverter manual about desulfating, there is a position on the battery selection that will cause the inverter while under charge from the generator to put 62 volts into the batteries. I'm hoping doing that will revive the batteries. I will talk to the techs at Aims next week. I watched a video today about a guy who used a stick welder to desulfate a battery, it actually worked and he didn't blow up the battery. This whole off grid experience has been a little stressful for a 73 year old guy. I can't say for sure what condition the batteries were in when I took delivery as the guy who installed the system didn't test the batteries just installed the system and turned on the switch. I now have all the equipment to monitor the batteries myself so hopefully all goes well from here. I appreciate the input, North Western Electric in Oakhurst recommends Trojan and Ceret batteries. Only time will tell.

[@robpratt4868]

so much information that my head almost exploded. stuff that other solar junkies are not talking about. thanks

[@VxO4fame]

I would like to see how it looks vs Lithium-ion batteries since they are more commonly used in electronics and have a better charge and power output

[@knurlgnar24]

Good question about other lithium chemistries and that would be another whole video. For the most part, however, LiFePO4 is better for stationary power applications in homes. The specific power and energy density characteristics are 'don't cares' for this application and cost, safety, and lifespan are better for LiFePO4 with the possible exception of Titanate tech. The primary reason people use other chemistries is either due to salvaging parts from vehicles or other applications, or re-purposing tech intended to be used elsewhere. There is even a large well-known company who re-purposes cells designed for mobile applications into stationary storage products resulting in an inferior product. I chose lithium iron phosphate for this comparison because it would win in a competition with any other lithium chemistry vs other lithium chemistries for this application.

[@D2O2]

Excellent presentation. If you do a TCO of trojan products you will find that Industrial FLA in an off grid application will have lower TCO than their Li Ion on a 20 year design life. Newer is not always better. Seems those that are pushing Li Ion don't fully know what they are talking about (using marketeering data vs. actual lab data or real world experience) and/or are selling Li Ion.

[@knurlgnar24]

I agree and that's basically what I did here. Low cost lithium cells from China are indeed lower cost on paper but they all come from grey channels and you never know what you're getting. There's a reason those big companies decommissioned those batteries and allowing sales to private parties and it's not because they like throwing away money. When someone is being had it's almost never the big guys with deep pockets. Buyer beware. I imagine this will change with time.

[@bullithedjames937]

Could you suggest a decent camera to start youtube stuffs?

[@knurlgnar24]

A lot of people use a high end cell phone and most use a separate audio track (mic to jack of old cell phone works just fine) and merge in editing. I do neither and could use the same advice myself as I'm using an older Canon point and shoot. Point and shoot cameras used to be the way to go but development of those has stalled over the past decade, prices have gone up, and production worthy cameras are closer to $1000. Are there any good cameras with optical zoom and stabilization, flip screen, and external mic input in the $500 range?

[@jamess1787]

"If you need a reminder to change your car oil, or don't remember the last time you changed your furnace filter..." Hahahaha!

[@teadott]

Welcome back dude, I have been waiting.

[@fredflintstone1428]

Brilliant videos. Many thanks for these.

[@knurlgnar24]

Glad you found the information useful. Best of luck with your solar project. This past year has been interesting with lead acid prices holding steady and lithium prices increasing. I suspect the long term trend will not be as kind to lead acid however.

[@lifebestlived]

Much appreciation for the information. I am planning a cargo trailer build around a 3000 watt pure sine 12v Samlex inverter. I’m pretty much a rookie in this regard. Wondering if running 2 agm 100ah batteries will be enough power to efficiently operate the inverter. I will mostly be running a small fridge full time, plus the following for very short periods; coffee maker, frying pan, led tv, led lights, phone or laptop chargers.

[@knurlgnar24]

The coffee maker and frying pan will be a stretch for two 100ah batteries but you might be able to get by. In a trailer I understand the limited space constraints you have to work with but my general rule of thumb that I tell people is 100Ah per 1000W of inverter as an absolute minimum. You did choose a good inverter so that helps your situation. 1500W is a tall ask from two 100ah batteries for any length of time - I don't know if you have room but I think you'll be much happier with your overall setup if you go larger with the batteries. This does depend somewhat on what kind of charging system you have, e.g. if you have an easy option to run a vehicle to charge them or whatnot. One thing to keep in mind is a mini-fridge alone will take 1 to 2 kwh per day to run, so two batteries will only run it for about half a day before the batteries need charging in order to power a heavy load like a coffee pot due to the lower state of charge.

[@alext8828]

Comparing batteries with different voltages, would it make sense to use Watt-hours instead of Amp-hours to determine the capacity of each battery?

[@HeinzMeulke]

Watt hours will be different depending on the load, see peukert's law for further study on the subject

[@knurlgnar24]

Watt hours would be better, I used the amp-hour*nominal voltage as an approximation. Peukert's law is misunderstood and I did a whole video on that years ago. It doesn't come into play in the context I'm speaking in this video, just the voltage sag does.

[@kgsalvage6306]

Did you get the 15kw battery bank yet? Are you going to make a video on it?

[@knurlgnar24]

Unfortunately no. The seller refused to ship the product due to the price of lithium batteries increasing (which is why I purchased it when I did). I did get a refund. If the price goes back down I'll try again. I have noticed a large amount of fraudulent listings since then attempting to capitalize on the battery price increases. Basically if it says 'grade A' stay away.

[@geworthomd]

You mentioned checking the specific gravity of the lead acid cells. How can this help? Let's say we have 20 batteries and each battery has 4 cells. At year two, a cell on one battery fails to maintain it's specific gravity within spec. At year 2.75 two more cells fail spec. At year 3, eight cells fail spec. etc. Each time, what are you going to do about it? What is the downside of not replacing those batteries whose cells fail to maintain specific gravity spec?

[@knurlgnar24]

If specific gravity is going out of balance you can rectify this by equalizing more often, changing ph of the electrolyte, or other methods as recommended by the battery manufacturer. Single batteries can also be replaced in the event of severe early failure which will give the battery bank about as much life as if that battery never failed at all. Primarily though, the purpose is to catch the problem early to avoid early failure of that battery.

[@alext8828]

I'm not looking to go off-grid. I need stand-by power when the grid fails. My battery will stay charged until an outage and then may need to run the house for an extended time. I have generators, but the outages kind of preclude dragging a generator out and feeding gas every few hours. They occur in bad weather and at night. In snowstorms and rainstorms. I need a deep drain battery that can sit on a charger full time and just wait. Any thoughts on how to attack this?

[@NiHaoMike64]

Occasional use favors lead acid.

[@curtgirardin6093]

I agree, if you're only using it occasionally (during power outages) then agm or lead acid might be the solution for you, as you won't be charging/discharging nearly as much. I am in the same boat as you as far as use type, so I am building an AGM battery bank. I just don't see any reason to spend the money on lithium for occasional power outage use. Now for those that are entirely off grid and need to charge/discharge every day and don't get enough sunlight to charge lead acid or agm at a slower rate, then maybe lithium is a better solution for them. I think it all comes down to your use case scenario and weighing cost, safety, maintenance, etc. I am going with AGM because I feel a little safer from hydrogen outgassing than with flooded lead acid. But that's just me. Hope this helps.

[@curtgirardin6093]

Oh and also a cool thing I learned today was that carbon monoxide sensors also are sensitive to hydrogen. A quick google search seems to have backed up that statement. So I just pulled out the C.O. sensor I normally keep in my "generator box" and plugged it in right above my batteries as an extra precaution.

[@morganbeasley]

Really interesting analysis. If i had road access I might go back to lead acid. For me though paying a freight premium of 1$ a pound to fly cargo to my remote location, Lithium pencils out a lot better. This is compounded by the fact that simply purchasing the batteries in Alaska carries a hefty freight surchage built in to the price.

[@knurlgnar24]

Makes sense. Everyone has to do their own analysis based on their specific circumstances and needs.

[@ericknoll3278]

You mentioned the difference in using a cheap versus good inverter. What inverters would you consider good at this time?

[@knurlgnar24]

It depends on your application and I have not been actively testing the newer inverters on the market at this time. A 'good' inverter in a whole-house scenario would be something like a SMA SI6048 or a Sensata Magnum 4448PAE. A less good inverter could be a large number of products including PowerJack, Aims, and many other no-name chinese brands. With those no-names you sometimes get a gem and sometimes get a turd.

[@Meleeman011]

@16:37 what kind of lithium battery?

[@knurlgnar24]

This video uses three specific batteries (one flooded lead acid, one AGM lead acid, and one Lithium Iron Phosphate) in the analysis and all references are to those three.

[@geworthomd]

Last question: How many calendar years are you getting out of the batteries in your system? How many years does it take you to recoup the cost of the batteries if you calculate the price per kw/hr you pay in your area from the grid? A five year payback on batteries that seem to only be lasting in a system here 6 or 7 years just doesn't seem to be worth it because there are other yearly maintenance costs, like 20 years on the solar panels that have to be amortized. If a catastrophic failure of an inverter happens once in 15 years that can throw the net dollar benefit per year over 20 years of solar panel life upside down.

[@knurlgnar24]

Battery storage is extremely expensive compared with grid energy. Batteries are only useful if one wants to be 'off grid' and one is willing to pay for that luxury. I've done lots of math/modeling and I estimate a solar/battery setup where I am located would cost 5x to 10x the cost of grid electricity over 20 years depending on base assumptions.

[@syror5000]

I saved alot of money. Watching you was a greate investment

[@rapunzeleh546]

i have about 10000 worth of agm in my basement for a solar/wind setup that i just never got around to setting up - we had wildfires for two years which meant road closures, so getting things in and out, holes dug and concrete poured for the wind turbines, and solar supports were a no go, then the company that i bought the mast from didn't send bolts, then they send the bolts but the HOLES were too small, then the controller stopped working and then and then and then.. finally got everything together, almost 5 years later and now, i put the cold crank tester on the batteries and it says to replace every $%^&UI one... does that sound right? the batteries were fully charged but not used for 3 years, then charged, but not used for a year and only just started actually using them a year ago... 16 440am 6v wired as 48 and one circuit with 2 led lights on photosensors lasts maybe 3 days.

[@knurlgnar24]

I can almost guarantee that your batteries are still good. You need to desulfate them and then they will give you a good service life. I would expect batteries to test 'bad' given your description but they are still very much in good condition once restored. If you still want to scrap them I may be interested in driving down and picking them up. ;)

[@erlendse]

Regarding the BMS (Li-x): There is a current sensing part, that can be done quite robust. It's basically a short block of "wire" the voltage is meassured over. The alternartive is a magnetic HAL-sensor, no direct connection from the BMS to the battery needed. There is also a break the connection at fault part, usually mosfet, but can be relay. It should totally be possible to get reliable. The BMS also sense cell voltages, usually done via high-ohm resistors. Water can wreck anything with constant voltage. There is also the option for balancing via various methods (this circuit usually does a small balancing each time fully charged) There is also a small interesting fact: the BMS may actually control the charger. The BMS basically sends a message to the charger with "use voltage limit x, and current limit y" periodically. I don't like the idea of a multible cells in series battery connected to a charger without data connection between charger and BMS. If you are going to DIY a properly done battery, you will have a massive wiring job! 1. all cell interconnects also connects to BMS via "ideally fused" thin wire. 2. One current sensor for the main current (usually on negative side if shunt) 3. two mosfets or relays + fuse (usually disconnects negative side of battery?) 4. "incident containment" container for the whole assembly. 5. CC-CV or even better smart-charger with data-connection to the BMS. 6. Cells should be safely locked in place, cabling too. 7. Likely something safely critical I totally forgot.

[@poolmotorrepairguyFL]

The Florida pool pump motor bearing repair guy approved ! that was good info

[@knurlgnar24]

I don't get the apparent joke here, but I'm glad you found the video useful!

[@poolmotorrepairguyFL]

@@knurlgnar24 glad you figured that out

[@fredreny6427]

HI I have this osp tiger claw 1500w inverter it smoked sparked no load was connected the trace that connects the mosfets burned up. Could you please take a picture with the inverter connections + - terminals facing you, looking on the left side of the board heat sink may need to be removed unless you have a inspection camera you can slide down under heat sink that's where the trace is. I need a picture of TRACE q 13 and the one next to IT not q14. I can send pictures of what trace is burned if that helps. I recall you saying that mosfets are in paraleel on the powerbrite is it the same on tiger claw? If you give me an email I can send you a picture of the burned trace or how the circuit traces connect on the board where it's not burned. So far found 4 shorted mosfets on ac board and 2 mosfets on dc board are shorted, should i replace the driver ic DIP chip and pwm DIP ic love your videos .thank you

[@minorukurata]

thanks for this video I learn that cycles is not the same a calendar age, so the typical error is dividing cycles into days and years

[@knurlgnar24]

I'm happy that you found this information useful. Cycle life is important in many applications but calendar life must also be considered. In off grid solar calendar life becomes a significant factor. It may or may not be a significant factor in your specific application. Solar tends to be a long-life application where 10-20 years is the goal. In many other applications people are happy with a product that performs well for 5 years after which they forget the upfront cost.

[@minorukurata]

@@knurlgnar24 great im in ev repair workshop I had two examples about age calendar I found a 2013 chvy volt with 30k miles with bad cell, that one example that age calendar is so important too, even volts engineers take carw not chargig more than 65% SOC and temperatures controlled by liquid and air condition maintenance 77F and manufacured by LG

[@minorukurata]

@@knurlgnar24 can I have your contact?

[@peteryoomla156]

Very interesting. As LTO becomes more available, it would be nice to include that technology too, as they last very long, are safe etc.

[@knurlgnar24]

Yes, it's an interesting battery technology but as of the making of this video it compared unfavorably against LFP so I didn't include it or research it as fully. That may change in the future. As of now LFP seems to be what the industry is rallying around, though already a higher voltage version of LFP is being produced for some EV applications which is incompatible with the LiFePO4 battery tech I covered. The future will be interesting.

[@franchase279]

Wondering why you went with a 6V lead-acid battery but did not mention the fact that you have to purchase 2 when doing the cost comparison?

[@knurlgnar24]

It's included in the comparison. Battery voltage has no influence on the comparison table other than requiring two vs one 12V battery at half the cost and half the size and weight. Most people will choose the 6V model for convenience to avoid needing a forklift to move the things around.

[@franchase279]

@@knurlgnar24 the full cost of two 6V batteries (1200 for 2 of these batteries) should be used in the cost/kwh information, no?

[@devoncole5789]

Wonder what the best sign wave inverters of today is

[@knurlgnar24]

That would depend on the specific requirements and goals of your application, but I wonder too! Some of the HF Chinese brands have gotten pretty darn good the last few years if you want a shorter life lower end inverter I have to say. That said I've NEVER seen a quality LF inverter from China, ever. Look elsewhere at reputable brands for those.

[@devoncole5789]

@@knurlgnar24 back in 2017 I bought a samlex 3000 for my camper well long story short some kids thought it was good idea to break in and vandalize my camper and that’s one the things that got taken I bought such for my camper because I seen how good yours did always loved your repair content and videos of such on inverters because atleast I got to see what’s inside without trail and error thanks for the reply

[@jfbeam]

I will _absolutely_ blame the buyer. How many people go to Sams, bring home a truck load of "marine deep cycle" batteries, don't read a single thing about them, and kill them in a year. They don't know how they're supposed to be used. They don't know they're *flooded* batteries that need to have their water level checked and maintained. (with distilled water, not fluoridated chlorinated tap water, or well / river water!) (They do this with lithium, too. But it's much easier to just _buy_ your way into a clue... buy LFP batteries, so buy a LFP BMS - and hope the chinese company that made the thing set reasonable limits.)

[@GroovyVideo2]

Im in RV mode - Solar - built 100ah LFP 6 yrs ago - using Everyday 30 to 70% discharge -No BMS installed - 1.3MW threw put - main things I like - quick charge - steady voltage - almost zero maintenance needed - I am starting to notice small loss in capacity -- battery price has dropped 35% ish in 6 yrs - Ive been using Li ion batteries since 1999 only cells to fail high output Lipo Pouch cell in RC usage - puffed but still store power -

[@thebugs4934]

top information presented in a balanced way. You are a treasure sir! Subed!

[@roland349]

Excellent overview!

[@hpaulfuchs]

Great presentation and I learned a lot. I recently bought 4 six volt Rolls flooded batteries, S-550, for my modest off-grid home system. I had read in several places I respect that the quality of Rolls flooded batteries is comparable to Trojan and at a more competitive price. Do you have a comment regarding this?

[@knurlgnar24]

Rolls is most definitely a reputable company that makes quality products. They cater more to heavy industry than Trojan does and make good products. As for pricing relative to value I couldn't comment.

[@jimmurphy5355]

At current prices it is possible to build a LiFePO4 battery kWh using cells from China for about $140 per kWh for the cells, and a BMS good for 200 amps continuo is about $200. I know you addressed the fact that you wanted to compare only pre-built batteries, but for someone that likes a DIY solution, knowing that you can put together a lithium iron phosphate solution for at or below the cost of high quality lead acid solution is a worthwhile data point.

[@knurlgnar24]

I agree. There are also commercial products available at lower cost today than what was presented here. I wanted to compare quality products to quality products which were available at the time of filming. This will inevitably change as time progresses.

[@leoschneider3570]

I was such an idiot, I purchased a lawn mower battery, and was using it as a deep cycle battery twice a weekend for three years, (using my small power inverter) and i never checked water in the cells, and I know you aren’t really supposed to use starter batteries as deep cycle batteries, but it did work, I am going to do your desulfurization trick on it.

[@knurlgnar24]

I wouldn't call that 'idiot' behavior. Lawn mower batteries are inexpensive and can be used for light duty deep cycle uses for a pretty cheap setup. Their lifespan tends to be quite short however so I suspect you're going to end up needing to purchase a new one. If that setup worked well for you and the capacity was enough then I wouldn't hesitate to buy another one. I used two lawn batteries with a UPS in college. They lasted a few years before positive plate corrosion got to them.

[@twwtb]

When considering environmental aspects of lead acid batteries, I think many mistake local handling with actual environmental impact. FLA batteries require more care than LiFePo to avoid contact with any acid and ugly corrosion that may have gotten on the outside of the case. This makes them more yucky in the eyes of many people. People are accustomed to seeing some corrosion on the battery shelf, hold downs and terminals under the hood of their cars. To them, this equates to environmental impact. It's not the same thing.

[@fratermus5502]

Excellent series, thank you. Consumers would be better off reading the specs and doing the math instead of gobbling down marketing hype. I have used all three chemistries to good effect, each when their strengths warranted. I agree that lifetime $/kWh is a metric of central importance. IMO the central issue in the *use case* is whether or not the batts will be charged to mfg spec regularly (preferably daily). If yes, FLA is hard to beat. If no, Li starts to look much better. This vid does introduce PSoC at 2:10, but few Pb batteries are able to tolerate PSoC. Carbon-foam seems to work as claimed, and maybe the carbon-doped stuff (like RE from Trojan) to a lesser degree.

[@knurlgnar24]

Thanks for your insight here and I agree. Lead acid, including lead carbon as in this video, still require a full charge once a week or better to maintain their health. Lithium does not require this. In many applications this is a strong benefit for lithium chemistries but I do still maintain that a properly designed true off-grid system is designed for 20-30% DOD per day during the worst time of year, and with such a system a full charge nearly every day will be accomplished. For those who wish to skimp on their system skimping on batteries are the easiest choice due to marketing reasons and misunderstanding of true needs, and therefore lithium gets more praise than deserved in practical applications. That said if I had a 'toy' I would absolutely choose lithium in most cases. Economics isn't so much a factor in that case.

[@blackmagic8115]

I wish you would do a comparison between 100 amp sealed batteries, lifepo4 and lead acid. I’m looking at a 400 watt solar system for a Transit Connect cargo van - weight, volume and price over 5 years are of major importance.

[@knurlgnar24]

I may not understand your comment because I think I did what you requested in this video series? In any case for a Transit camper/cargo van I would highly recommend LiFePO4. Lead acid is heavy to haul around and doesn't work well with an undersized battery bank which you will have by necessity in a vehicle for space reasons. For stationary applications the math is different. Consider that weight accounts for about 50% of fuel use, calculate the weight percent gain of your vehicle due to batteries, do the math on miles you plan to drive over 5 years and there's a decent amount of raw fuel cost that may come out of it in addition to the additional wear on your drivetrain and chassis due to weight.

[@dennisolsson3119]

Wonderful! There are auto fill valves for the distilled water for lead acid. Shouldn't they have a version with of gassing hose connection? It seems like if you can handle the gas and monitor water level and perhaps automatically fill (I know auto filling is a path to other problems) them most of the cons are gone. I'm also thinking of a used market. I have seen flooded LA batteries being cleaned (unclear of the success rate) to be reused. AGM would be harder and lithium could at best be split into decent/bad cells. Also your desulphation videos show a big benefit of reviving mistreated LA. I love lead acid because they are really forgiving for mistakes and can take abuse... But I am not yet experienced in resurrecting them, so it is mostly based on second hand knowledge.

[@knurlgnar24]

Good points. I also wonder why more lead acid batteries don't have fittings for venting gasses since it would be so easy to add and has been done in low volume applications for decades already. AGM can only be recycled and not reconditioned as far as I am aware. I suppose that could be a benefit of flooded batteries but that's probably beyond what most hobbiests would want to tackle. I'm wary of all the hype surrounding re-using degraded lithium cells. While it clearly can be done and those cells are still useful - what about failure rates? Batteries used in industrial applications are EOLd while they are still working perfectly fine for good reason, not because businesses want to throw away money. If those cells were truly still viable they wouldn't be selling them off in the gray market to suckers on eBay. There's something fishy going on there that I don't fully understand, and when someone is being 'had' it's usually the little guy.

[@NeilBooth]

Why did you exclude gel batteries? Are they bad?

[@knurlgnar24]

I see no significant benefit to gel batteries in this application over other types. They are not 'bad', just not optimal for this application. They certainly can work but they have unique detriments while not really having any significant benefits over AGM batteries.

[@NeilBooth]

@@knurlgnar24 where I live a 200ah gel is ~200$ but a 200ah agm is nearly ~400$ would you recommend the gel over the agm at that price difference? What are the detriments besides cranking power? Thank you

[@virgelmccluskey8700]

what battery would you suggest for use on a sailboat house bank with limited space. Say 2' W by 2' Lby 1.5' H.

[@knurlgnar24]

LiFePO4 for sure if you want a good storage capacity. If you only need a couple of kWh then I'd stick with lead acid for cost reasons. If it's a boat and it's seasonal then you would want to consider maintenance also. A lithium battery you can disconnect and leave for the season without issue, a lead acid battery should be charged every few months. Your charging system might be made for lead acid though...

[@geworthomd]

Could you comment on reviving dead batteries, the three types? Charging a 12 volt battery with a 24 volt charger 20 min on 30 min off for 6 cycles, there are recipies all over the internet. In lead acid the sulfate crystals that accumulate on the surface of the lead plates, can they be acid burned off or over charged off or even taking the case off and scrubbing the plates? By the way, what solar charge controller and wind generator battery charge controller so you like when looking at ways of extending calendar life? I never get more than 6 or 7 years out of AGM or lead. I cannot afford to experiment with lithium.

[@knurlgnar24]

6 or 7 years sounds pretty good for most AGM batteries unless you get the premium ones like mentioned in this video. I have an older video on desulfating batteries, but did a newer one recently. Here is part 1. kzbin.info/www/bejne/hJSrXoetja-Do7c

[@willyamsshop1457]

@@knurlgnar24 By accident may have recovered two very old Powerware AGM batteries (10+ years) in my wife's aunt's wheelchair.. she has crippling arthritis but rarely uses her chair unless we are visiting. Two 12v in series for 24v, were down to 9.3v each. Put on 24v charger, when they started getting warm, disconnected. Cycled on/off about 6 times, until they started working again. When we left, I put a cheap mechanical timer, minimum setting one hour on, and left the charger on the batteries. When the charger turns on, in around 5-10 min the green complete light turns on. I'm hoping this will keep the batteries hot until our next trip up, she's out of state so we can only visit every few months.

[@gonzo_pix]

So if I have understood your explanations correctly, then it should make the most sense (for my application) to look for used AGM batteries and thus gradually expand my storage. The idea would be to start with 4 or 8 new batteries in a 48V system so that I have a solid base. Since I live in Germany, of course I have to orient myself on the market here. Starting with the Northstar batteries, what are the technical specifications I should look for? For example, I can get a 110 Ah AGM for the equivalent of $144 at our online store. I guess that is compared to the Northstar kind then rather Walmart Nievau.

[@knurlgnar24]

I cannot say what makes the most sense for your specific application, but often the best choice is to use what is available to you at a good value. The most important metric in my opinion for an off grid installation is cycle life. Other metrics matter certainly but that one metric is highly important. The Northstar Blue+ batteries are a very solid choice as are the leoch AGM industrial offerings which were not mentioned in this video. I am sure there are others which vary according to the specific market you reside in.

[@jimmurphy5355]

Did you ever get and test the cheap lithium based battery you ordered from China

[@knurlgnar24]

Unfortunately it never arrived due to the shady nature of these gray market distributors. There are 'better' alternatives now vs building your own such as LiTime (no affiliation). When purchasing from Alibaba or Aliexpress you will nearly always get used or failed-test cells. I've been considering making a video about how the electronics distribution system works and why 'grade A' cells are pretty much always a scam. The industry simply doesn't work that way. If you ever see 'grade A' advertised, RUN.

[@jimmurphy5355]

@@knurlgnar24 Raw LiFePO4 cells can now be reliably bought from Amazon. They are still probably not really Grade A, but they arrive in a few days, and are easily returned if they are bad. As of today, buying cells from Amazon costs about $200 per nominal kWh.

[@usablake]

So weird. I was like, “I wonder what knurlgnar would think about the Solark inverter and the LiFePo batteries. Better check and see.” And here is one of those topics! Wow. Now they need to send you a Solark!

[@knurlgnar24]

I don't do any of this for the money and as such I don't especially like product review donations (though I do have a few vids on that). But I'd be interested. I'm not making promises but I do have parts on order from China to do some LiFePo4 projects. As prices on those batteries has gone up in the last few months I expect them to cancel my order. Everything is shady over there - the reputable brands cost much more and that's what this video covers. We'll see.

[@maxusboostus]

Have you heard about Lead Crystal Batteries? from what I've read they can cope with more abuse than normal Lead Acid, but they cost more. Interesting Video.

[@maxusboostus]

@@lexiecrewther7038 oh dear, not heard that. thanks.

[@Engineerd3d]

I'm curious what your thoughts are on the so called "edison" batteries. Supposedly these are called the 100 year battery. Also used in NYC subway emergency systems for about a century.

[@knurlgnar24]

I believe lead acid won out for good reason years ago. They have niche applications. I'm not all that knowledgeable about Edison batteries but from what I know I wouldn't use them for any application I can ever see myself needing batteries for.

[@Engineerd3d]

@@knurlgnar24 the thing is there is a company remaking these types of batteries for usage for solar systems. Apparently their major down sides were size and weight. However they are way more durable to abuse. At least that's what the general public said. In either case you answered my question. Also longevity is supposed to be superior to all.