Battery Desulfation Demonstration Start to Finish - Part 2/2

In this video I demonstrate the full desulfation process using a lab style power supply and a lab style electronic load. After editing part1 of this video I realized it would be very boring so I set the project aside, but decided to pick it up again later on to finish it as I thought it was still informative. Please let me know if this is something that interests you.
Where to purchase the Lab Power Supply used in this video:
Amazon
amzn.to/3fCunJp
Where to purchase the Electronic Load used in this video:
Amazon
amzn.to/2V9yZx0
FTC Disclosure Statement:
Some links may be affiliate links. I may get a commission if products are purchased using the links provided.
EDIT - I realized after uploading but before posting that if this battery sat on a shelf for 5 months and held its voltage well that it does NOT have a cell with an internal discharge issue. I suspect it just has a higher internal resistance than a new battery.
I cannot guarantee against improper use of the information contained in this video, nor guarantee against unintended consequences of replicating what is seen in this video. I assume no liability for property damage or personal injury incurred as a result of any of the information contained in this video. Be sure to read and follow all safety instructions for any equipment seen or implied in this video, and use safe practices when working with potentially dangerous equipment. No information contained in this video shall create any express or implied warranty or guarantee. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained in this video is the sole responsibility of the user.

[@wolw66]

Maybe it's just me, but I find these kind of videos entertaining, not boring.

[@knurlgnar24]

You're a weird person. I like you.

[@dave44052]

These videos make me want to learn more about the equipment and what you can do with it. Besides i am tired of buying farm machines batteries they die and freeze over the winter great ohio weather

[@knurlgnar24]

@@dave44052The best thing is to take the batteries out and store them where they won't freeze and charge them every once in a while. Otherwise a previously frozen battery will usually recover to some extent if you desulfate it. I've done this many times and they usually give many years of service after even though their reliability will always be in question: It may last 10 years or it may last 1 month. Freezing a battery isn't good.

[@dave44052]

@@knurlgnar24 it such a pain to take them all but i do need to I agree. I think im going to order a power supply should i get a 30v 5 amp or 60v 5amp they also have some 10amp

[@dave44052]

Any thoughts on this? Thanks

[@miketrissel5494]

Figured you needed to have at least 1 comment for 2023... Your video was about as exciting as watching a battery charge. 🤣 At the age of 70, this is about all the excitement I can handle. Nice Job

[@knurlgnar24]

And that's exactly the kind of excitement I deliver!

[@Slimpickens45]

This is the content I joined youtube for.

[@ArnoldsDesign]

I just got a college course on battery restoration. Very informative. I have those same sealed 12v batteries for a stair chair lift that I'm recharging now with a Beleeb 30A charger, which is supposed to desulfate with pulse and discharge cycles. We'll see. Meanwhile, I also have an old school Schumaker dumb charger, and a 10A, 30V DC power supply I'm going to mess around with some old batteries I have here and see if I can restore. This is really cool.

[@Ian-pe9rj]

On that electronic load use the sense terminals and connect them to the battery terminals, that will solve the voltage drop issue.

[@knurlgnar24]

Thats' to EZ. I did collage gud. www.youtube.co/watch?v=wv4eTE0aUiQ Next time Gadget. Next time.

[@jefferyhymiller8189]

Ullllu

[@zolan4277]

Looks like you don't have a 2024 comment yet. You are awesome! This video is very interesting and useful! Thanks!

[@knurlgnar24]

Thank you!

[@g0fvt]

Fascinating, obviously with AGMs it is difficult to see what is going on, from my observations with wet lead acids during desulphation you get localised bubbling where a part of the plate has begun to recover. The bubbles of course are not conductive so the cell internal resistance will rise temporarily. Lead acids seem to recover very well, obviously there are other modes of failure that cannot be reversed. Good to see you back.

[@LeeLipinski]

Glad to have you back and thanks for the video. Please add one vote for a discussion of how you maintain your battery banks. I have a bunch of group 31s that I'd like to play with/set garage on fire. Nostrovia!

[@chrober247]

Great stuff! Literally just what I needed. Thank you so much for sharing your knowledge.

[@tinysolarshack9615]

Great to see you again. I always appreciate your videos! 👍👍👍👍⚡️⚡️

[@willtomkinson8083]

Love the philosophical intro.

[@a.bakker64]

I am glad you did this ’exercise’ so I don’t have to figure this out. Learned a lot in both videos. Thanks!

[@ElGatoLoco698]

I'm impressed with that battery bank. I'm surprised it's still working that well. It was pretty old and used when you first got them and here we are five years later and they're still pretty good.

[@ElGatoLoco698]

@corey Babcock I think his batteries were in service for several years before he saved them from the scrap heap and that was over 5 years ago and many of them are still at 100% capacity. He made some interesting videos on them.

[@thakery5720]

@corey Babcock I was amazed to find, when I had to replace my car's battery, that the one in it was the original one from the faactory. It's date marking showed that it was 11 years old !

[@knurlgnar24]

I know this is an old comment but I still use these same batteries at least once per year as a test to demonstrate how they will perform powering my household needs with generator backup. No issues so far.

[@yvineikeland8734]

Thanks a lot for this video. I am currently trying to salvage two similar batteries that has been totally discharged. I am a bit at loss about when to stop the high voltage "overcharging". The thing to watch out for, you say, is temperature. How high temperature is "ok"?

[@halflife82]

I really appreciate all the detailed narrative as you go as I learned a couple things listening along! Thanks so much. I appreciate looking at batteries more like someone like myself thinks, using theory and application in a live scenario. Much appreciated. Sub’d

[@knurlgnar24]

Thanks for the support! This channel is not very active at the moment so videos are currently posted infrequently. Perhaps in the future that may change.

[@michaelmorris1802]

Most Excellent... I happen to have a completely dead AGM Car Battery that won't take a charge... down in my barn, I also happen to have an old school battery charger that I don't use anymore... hoping it still works... I'm about to hike down there and get it, and hook it up to that battery and just see what happens in a day or 10. :)

[@atotalmoron]

This video has made me a little less dumb. Thank you for spending the time to do this.

[@phasekay]

You're very good at what you do.. A great power bank you got 💪

[@TheBlackadder-Edmund]

I am not sure why I have a Battery recovery fetish... But I love this ;P Thanks

[@knurlgnar24]

If it's not in the DSM-5 it should be, I share your condition. My condolences..

[@garbleduser]

@@knurlgnar24 I thought this was the support group for that?

[@GeorgeWMays]

Very cool. Thanks for a very useful and informative video. It is truly appreciated.

[@n3lee]

Glad to see your back at it again!

[@4runner4ever83]

Now i understand why my charger is charging my car battery at 16v and at 7.x amps and slowly changing to lower amps as it completely recharges. Thank you for explaining.

[@collinsmwaura1833]

Thanks Knurlgnar!!! That was an informative video, it was of great help.

[@akirchner3]

I would love to see a video on maintaining batteries...

[@MrArinder]

@@LewisMoten 7 Months Ago!!!🤣

[@philipng6598]

I have 4 AGM truck batteries that were fully discharged and kept that way for over 3 months when the truck was sitting in the shop, and somehow I accidentally kept it undercharged at 13.5V for a month before running the truck with them in. The sitting voltage went down to 12.4V so I swapped the batteries out and have the AGM batteries worked on. After watching the video I fully discharged my battery (down to 11.15V since there’s a huge voltage drop to the inverter and the inverter shuts down at 10.5V) with the lowest sitting voltage (12.44V) with a 60W fan (that’s all I got in the truck that I can use while being on the road) then charged it back up and run the repair mode (voltage goes up to 16.5V theoretically). That battery is now sitting at 12.51V. I am gonna hook up a battery monitor to count capacity and to repeat the process until it gets between 12.8-13.0V and work on the rest of the batteries too. Hope it works I am hoping to use them for another 3 years before needing to replace them

[@CaptainDangeax]

thank you for this very insightfull video. Just bought a chinese active load on Amazon to revive 3 old batteries laying in my garage

[@knurlgnar24]

nice! I have found numerous uses for my electronic load.

[@400djl]

I am interested in a video on properly storing batteries. Glad your back making videos again.

[@dashtesla]

keep them outside give it plenty of sunlight, rain and throw some salt on the terminals every now and then :)

[@AndyDuboskySaysFuckThePolice]

Yes specifically deep cycle battery's that seldom get cycled

[@Ge-Fat]

THE LEGEND! welcome back AGAIN :D

[@tasmedic]

I suspect one could make significant amounts of money simply using the information you're imparting in these excellent videos.

[@knurlgnar24]

Wish I had known that. ;) There are industrial battery re-conditioners who use similar processes. They often also change out the electrolyte and such in some valuable batteries. A quick search for used forklift batteries should show who does that in your area. As shown here there's no magic to it and one can do this themselves with a little know-how.

[@oldroscoe2590]

A good winter project, trying to desulfate some old batteries I've accumulated.

[@closertothetruth9209]

interesting and hopeful results

[@GUCR44]

Thanks for this vid I learned alot.. Stay cool and keep making vids! Peace man

[@davidhall1779]

excellant instructional video. I really needed to watch this as 1. Im having issues with my 12V LA deep cycle marine batteries. probably more a load V charging problem, Im so bad with batteries they scream quietly when they see me coming. that aside I invested $100 in a genius 10 NOCO charger that has a battery “repair” mode, didnt seem to do anything. I get 12.4V on the battery but low SG readings. the batteries are only 6 months old and I have disharged them and put them away before recharging a few times so I either ruined them or theyre heavily sulfated. going to look into one of those lab power supplies and try the method you demonstrate here. it gives me hope and I like that. glad to see you back, hope you continue providing your version of most excellant content.

[@knurlgnar24]

If your batteries are only 6 months old it is pretty much a guarantee that they will recover to near 100% with the method shown in this video. Irreparable sulfation damage take more time than that. I am not surprised that the NOCO charger didn't work - that isn't a negative comment on that particular charger, just a comment in general on the state of chargers today.

[@egn83b]

Great info. I hope in the future you can explore some junkyard ev lithium batteries on youtube. You seem to have a balanced view of the battery process.

[@user-se2pb5yx5p]

Best video. Thanks a lot

[@mbabiasc5359]

Excellent. Thanks!

[@davelowe1977]

Nice one. Very interesting.

[@slybunda]

thats a good way for me to revive some old batteries to use for running led lights on an outdoor Christmas tree.

[@poolmotorrepairguyFL]

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

[@TRYtoHELPyou]

Cool man. Tks for sharing

[@jenntek.101]

Excellent!

[@tarunarya1780]

thanks. great videos

[@papaikarmakar84]

You earned another subscriber

[@knurlgnar24]

Awesome! Now I have 2!

[@KentHenry8]

LOL. The gaggle of alligator clips is a popular technique on my bench as well.

[@MrDubje]

I once tried recovering a couple (2 x 12V in series) of small SLA's from a standby application (automatic door back-up, on charge basically for 24/7 ) that were so bad that when you pulled any current out of them the voltage would just drop to near-zero. Open clamp voltage was about 11V. They didn't take a normal charge any more (no current). Since I figured they must have boiled dry over the time they were installed, I opened the top cover plate, and removed the rubber caps (which actually serve as valves). I added distilled water (you can buy it easily in every supermarket for less than 1 euro for 1 liter) to each cell, while carefully noting if I started to see the water level rise above the absorbent material. Some cells required more, some less water. Excess water was removed by shaking the battery upside down in the kitchen sink (It doesn't become acid immediately. That takes a good amount of time, so don't worry) Now that I knew about at least one parameter (water level) of the physical condition of each cell I went ahead and put them on the lab supply set to 20V/current limited to 500mA (small batteries). I put my bench multimeter (34401a) in series to monitor the charge current that started out below milliamps... The charge current rose to a couple of mA in 5 or so hours. I let it charge until I was satisfied and stopped charging. With a small incandescent light bulb I tested to see if the battery was able to deliver some current and discharged it. I repeated this multiple times with some experimentation but safe limits set and I was able to recover both batteries, but unfortunately one of them had developed a bad cell that would always run hot both when charging and discharging. While the other good battery after charging and sitting for 24hrs still had over 12V on its terminals (over 2V per cell = good/fair IMHO), this one dropped to 10V, indicating one failed cell. While charging I was able to clearly hear the batteries "boil", which indicates that the acid is doing its thing and the added water is being converted. During the recovery process I monitored the temperature "evenness" with a thermal camera to avoid problems. After recovery I put the rubber valves in place and taped the cover plate loosely on, the one good battery was being kept as a hobby thing, not for critical applications anyway. When replacing the top cover plate I made sure not to block the vent path. Needless to say this recovery didn't make any economic sense, but it was fun experimenting!

[@knurlgnar24]

Nice work! Most of the time this sort of thing isn't really economical but on occasion it can be. There are businesses that specialize in recovering and reselling forklift batteries for example.

[@MrDubje]

@@knurlgnar24 Yup. It was a good exercise. Later my neighbour put his old car battery on the side walk, a big ass one for a large Mercedes Diesel. I scaled up the charging and discharging with my huge lab supply (up to 20A) and a massive electronic load form my employer. I used jump starting cables to connect the battery to the load. They got hot. In fact, I was lucky to play it safe and be physically present and monitoring, because one of the terminals' isolation caught on fire (due to the high temp cause by the contact resistance) while testing at 80A(!). Unfortunately, that battery had a defective cell as well and after charging and sitting for 24hrs the clamp voltage dropped to below 12V by itself. I did get some cash out of it when recycling though, as it was very heavy!

[@mikecollins521]

I know this is two years old, but i''d really like to see you do the same thing to power tool batteries. NiCad, and the Lithium ones. Those drive me crazy. Plus maybe discussing how to charge them (not going all the way, running them a bit before sitting, NOT leaving them on the charger) and maintain them for maximum life. Love your channel!

[@knurlgnar24]

Lithium is a whole complicated ball of proprietary but/if/when's. I generally tell people to just buy a battery especially since mistakes can end in violent fires. With NiCads I've definitely had success with revitalizing them but it never lasts long before they die again. Hardly worth it in my experience. Lead acid is SOOOO forgiving. Even after terrible abuse one can often bring them back to a serviceable condition. If you're interested I did a video a while back about lithium vs AGM for solar applications. Lots of good info there. You have good advice regarding your tips!

[@mikecollins521]

@@knurlgnar24 Thanks for responding! Is there some formula for calculating the lowest voltage you can let a battery drain to for cycling or is the percentage different depending on the voltage of the battery? If not, do you know the low end cutoffs for 12, 6 and 18v batteries? Is there some chart somewhere you know of that shows this? Thanks, again!

[@jjiacobucci]

Thank you

[@gor4988]

Hahaha if you were going to lose 5 months 2020 was the year to do it Great Pt 2 👍

[@Michel-Artois]

Very interesting experiences and explanations, lot of thanks!👍👍 ...But what a pain to try (not always with success) to recover a sulfated battery with falled voltage ...and still all cells alive! . I think it can only run with a battery with still good lead plates, only sulfated by negligence. If one cell is dead or short, or all plates too much "tired", it's a permanent issue. ...It 's also the demonstration that lead technology becomes slowly out of order : necessary maximal charge permanently, progressive inevitable sulfatation, quick auto-discharge, maximal weight, and random lifetime. I use now most of all Lifepo4 batteries , more expensive, but I build them easily : very stable, no sulfatation, very minimal auto-discharge, accept long half discharge without any issue...(it's the best way to keep them safe if not used) , very regular amps/output until complete acceptable discharge...and 10/12 years minimal lifetime. And if one cell is dead we simply change this cell if the IR of the others can accept the changing. But it's another choice. Friendly, Michel

[@josevencatareddy5084]

I found it very useful for what I am doing at the moment . ! have watch both video twice , the second view gave a lot more informations about voltage and current that CAN flow in a battery and it`s effects on the resistance down in it . I am testing a little solar system for only a room and does not want to invest high amount of money on the test . So il will rather find some old batteries and wake them up for all my test . I have watch 100 of videos about reviving batteries ( Epsom salt/ baking soda / DC stick welding / and more ) I will probably mix some of theses and take the most of it to revive the battery closest to 100% . Will probably empty one totally , neutralize all acid in there then rince to get all residue out of it then refill with epsom salt solution before making the desulfurization then rince it again and add new diluted acid before a normal charge . the experience will demand some trial and error may be then figer out what is the best combination . A car electrician has some 100 + batteries lying in his shop , so I will make a deal with him to get them . Hoping I may make some money from them while I can also make a power bank from some of them for my solar things . Your video interested me because you did mot open the battery at all , But in that case the lack of fluid covering the plates will probably never give a long shot for the battery I think .But It worth the lesson . THANKS .I will give a like and subscribe to your chanel

[@knurlgnar24]

If you get old car batteries make sure they have the proper water level before doing anything else. I wish you well in your project!

[@josevencatareddy5084]

@@knurlgnar24 Yes of course . I already tested a small bat that had only 2V and after adding some distilled water it came to 4.3v without any charge and it has lied like this for 4 days and still hold the 4.3V . Will put it on charge as soon I get a god weather ( dull rainy weather at the moment ) I will force 20V at 6A from solar panels .So I need sun lol. Thanks for your reply

[@uxwbill]

A while back, I found a new in box APC UPS that had sitting for more than twenty years. Not knowing about any of this, I gave up on its batteries as hopelessly dead. They've probably long since been recycled. Now I wonder if they might have come around... Even with good batteries, the UPS had a hard time coming back to life. At first the relays inside would buzz when the power button was pressed. Then it'd buzz and produce a painful sounding beep. Today it's fine. If I had to guess, I'd say it was capacitors reforming...

[@knurlgnar24]

That's a good guess on the capacitors. I suspect if those batteries were new and never used they would have come back. No guarantees though!

[@MrJdsenior]

Good lord, someone who actually checks the capacity afterward. What a concept. I think most commercial desulfators go to about 60 v with a more or less constant voltage ramp at 13 khz or so to the normal charging voltage, and the pulse width for the spike looks like about 20% just guessing from what I remember of the waveform. I think the pulses are what break up the sulfation. I've seen actual picks of the sulfate removal from the plates and it looks quite good. Not many actual current load voltage time curves. I would like to see your battery maintenance vid, will search it. Thanks for spending time and actually DOING something. As an EE I appreciate it. The fact that you don't sound like a moron is quite nice, too. I think there are more brain dead videos on resurrecting bad batteries than about any other subject. I saw one goofy kid salt a battery that had been laying around forever, and claimed it was functional now because he could get teeny tiny sparks when shorting it on jumper cables. Nice vid, thx. I can tell you what would REALLY help battery packs is if the manufacturers would voltage monitor EVERY cell in the pack, and as soon as one hits it's minimum spec'd discharge voltage, SHUT OFF THE BATTERY by just opening the circuit. If you did it such that the shut off occurred at about 85% discharge I expect they would last MUCH longer. As soon as you back bias a cell you are degrading that cell at a VERY high rate, time wise. Dead is not great, especially for long lengths of time, but charging them to a negative voltage is MUCH MUCH worse.

[@HaploPrime]

> Dead is not great, especially for long lengths of time, but charging them to a negative voltage is MUCH MUCH worse. Can you further elaborate on this to someone who isn't an EE?

[@MrJdsenior]

@@HaploPrime It has to do with the chemistries involved in some types of batteries. In the case of lead acids (car starter batteries) leaving them at exceedingly low charge for any period of time causes sulfation on the lead plates, usually rendering at least one of the six cells virtually or totally inoperable. In other chemistries, like NiCads, there are chemical processes when charge is reversed (happens when a cell in a pack loses capacity) and/or when the pack is discharged under load to extremely low voltages. In that case chemistry the cell is not designed to operate with occurrs, usually leading to irreversible damage, like some chemical bond occurring that is very hard to break. You can sometimes fix this to some extent, but the cell will probably never be the same. This is why cells are carefully matched for capacity for a given pack, but by definition there is ALWAYS a weakest soldier, and he will get felled first. If you don't deep discharge (quit discharging at the recommended pack voltage and recharge) this problem can be avoided, at least for the normal expected charge/discharge cycles, in that case about 1000, but I have had battery packs go FAR longer than that. Ni Cads can be stored almost indefinitely fully discharged, from my experience, but just one reverse charging will degrade a cell significantly, a few times will destroy it, and it will have virtually no capacity. Li Ions I don't know all that much about, but IIRC they are not supposed to be discharged below 1.1 V for a given cell. I also understand that in a hybrid or electric car battery, for instance, charging them to about 85%, and not letting them discharge below about 15% of recommended, AND keeping the cooling fan filters changed or cleaned regularly will VERY MUCH extend the life. You can probably get more/better info searching the web. I am certainly no battery expert, not even a little bit, but that is some of what I have found and/or understand to be true. Hopefully I got it right. NiCads and lead-acids I'm pretty solid on, some of the later technologies not as much. Hope this helps.

[@joecool4656]

I tried a riding mower battery recondition mode on a Harbor Freight 12V charger with no knowledge going in. Battery got so hot I could see vapors escaping and the sticker detached from the battery. Did not save the battery. With this video and with some other research I’ve done, I feel way more confident trying something again in the future. I should have been more careful, and now I am also realizing more cycles on the battery may have improved it to be usable again. Thanks!

[@knurlgnar24]

Wow! That Harbor Freight charger definitely put you in a dangerous situation! (boiling hot sulfuric acid is serious stuff) A good rule of thumb for batteries is to never let them be hot to the touch. Shortly after 'warm to the touch' is thermal runaway if your charger is not current limited properly.

[@joecool4656]

@@knurlgnar24 I figured so. I have a thermal gun and I will make sure the internals do not get warmer than 140F which is what a lot of other KZbinrs are throwing out as a generic maximum number.

[@fredflintstone1428]

Another brilliant video. I wonder if the battery's history played a part in your results. If it has come out of a UPS, then wouldn't it have spent a lot of time being trickle charged just to compensate for losses?

[@knurlgnar24]

Hi Fred! Based on what I discovered in this video and where I salvaged it from I suspect this battery was never installed and instead was stored for a long period of time and 'failed' self test immediately upon installation and was then scrapped. Usually used UPS batteries are only useful for scrap.

[@remakingcenter2854]

I like this video

[@AB-uw3os]

It is quite easy to add water to this type of battery. Just have to take the top cover off. Perhaps you should try that with it, and also with your larger batteries.

[@shawn7913]

I have a Foxwell battery tester that I'm still learning how to use. Would that work on a battery this small?

[@gregor.potrebujes]

Vstop @ 10.5V, and then Vstop @ 9.5V... maybe that's why you got much more juice out of it the last time... however, I'm gonna give it a try :) thank you for ideas...

[@greatwhitenorth762]

Wow, i had no idea there was so much to learn and know about recharging a "simple" lead/acid battery. For starters i didn't know of 'lead-antimony' vs. 'lead-calcium' type. And the process of repeated charge/discharge cycling to work the capacity and voltage holding ability higher and higher....never knew that either. Fascinating stuff. Thank you for making these very educational vids. I have a question if i may; what do you mean by "controlled over-charging"? I think i understand the "controlled" part (controlling what voltage to push the process with, and also controlling how much current to push), but i'm unclear on what you mean by "over charging". P.S. New sub.

[@knurlgnar24]

I wouldn't consider 'controlled overcharging' to be a technical term as it is more a description of the process. A sulfated battery when charged according to standard charging procedures as documented by the battery manufacturer will stop accepting charge well before it is truly charged. The sulfation isn't going to be converted back into useful active material in any substantial portion unless forced to by charging more aggressively than normal use procedures. Even equalization procedures don't really reverse sulfation to a significant extent in most cases as it is too tame to do much. What is needed is an overcharge condition that goes beyond ordinary use procedures. An overcharge severe enough to permanently damage the battery is required and this must be controlled by the user for obvious reasons. Fortunately the easiest part of a sulfated battery to damage is the sulfation and so it can improve the battery performance at the expense of some irreversible corrosion and shedding of active material of the battery plates, something that would otherwise be highly undesirable in a battery that is in good condition.

[@greatwhitenorth762]

@@knurlgnar24 Thank you for the reply, i understand now what you meant/mean by that term. But still unclear on whether you're referring to voltage applied or the amp-hour capacity that you push the battery to. How does one know when they've over charged the battery to an ample degree without going too far with it?

[@gssrustenburg]

Great explanation. Can a gel bat. be desulfated in the same way, or can a gel bat. not sulfate? I have gel bat. with almost no capacity 1 year since new.

[@knurlgnar24]

Do NOT use this high current method on a gel battery as it will cause permanent bubbles in the electrolyte which, hopefully, is not already your current problem. You can instead use a lower current for a much longer period of time and the general process will still work. It may take an order of magnitude longer though.

[@billryland6199]

You need much heavier wires when discharging to get accurate voltage readings. Too much resistance in small wires. Also, use the sense terminals to get accurate battery voltage.

[@jameskrivitsky9715]

Thanks K-G, helpful to watch your process. Have you found it advantageous to pop the cover & caps to add water to the cells ? What about any chemical additives ? JwgK a subscriber from previous years

[@mwilliamshs]

No cover to pop on this sla battery

[@eDoc2020]

@@mwilliamshs Usually the plastic plate on the top comes off easily, then you see six rubber caps. When I say it comes off easily, one time I had it come off accidentally. Usually it's not that easy but it's certainly not hard.

[@mrgreenswelding2853]

What does it mean when the voltage amperage doesn't decrease? I did add concerntrated sulphuric acid to it.

[@garypowell4565]

I have a 2 year old car battery that I converted into a magnesium sulphate electrolyte aka:epsom salt and I've rinsed it out with baking soda and water about 3 times, added the epsom salt and distilled water mix, and cycled it and zapped it with a 10 amp charger on muanual a few times, dumped out the epsom salt mix and added some new with a little more e salt, and repeated the process a few times with the charger, and have had it setting with a 1 amp trickle charger for over a week and after letting it set for a few hours it settles at 12.2 volts until i put a load, a 12 volt headlight bulb i turned into a 12 volt lamp to drain the battery with to recycle it, and the voltage hangs at 10.9 volts and just slowly discharges. Is this epsom salt gonna do the trick if I recycle it some more or should I go ahead and put the acid back in it. I'm just using it as a backup battery for when the power goes out or to hook my 500 watt inverter to it when i need it. It's a starting battery I know, a walmart neverstart 730 cca, but I just want it as an emergency battery, and just keep it topped off for an emergency. Any educated advice you can give a greenhorn?

[@knurlgnar24]

I'm not a fan of adding epsom salt to batteries to revive them as the chemistry doesn't make any sense - meaning there is no chemical mechanism at play to allow it to do what is claimed - but what you did in terms of replacing the electrolyte does make sense. I have to say I haven't tried this before but it sounds like what you did is very similar to what some industrial battery recovery businesses do. How to properly reform it back into a traditional lead acid battery? I'd have to do some research as I admit I don't know how.

[@heathfox573]

thanks . H.

[@TPWW-tr3rr]

Thanks

[@pasiturpeinen9273]

This was very interesting video indeed. You seem to know your subject. Ive been watching few videos on desulfation and yours seems most professional approach. I was especially interested the part where you mentioned that you have used lab power source to desulfate individual units on 1000Ah battery bank. This got me thinking if I could recondition my eletric forklift batteries using same method? Before anyone asks, yes total noobie here. Maybe lab power source is just too small for forklift battery bank cells. Short background info: noticed that my battery bank does not hold charge as it shoukd be, measured the acid concentration in the electrolyte and all cells are between green and red in the white area. pretty much center of it. What do you think should and could be done to this battery bank to recondition it? Thank you already in advance for any help you can provide. Very informative videos, I need to watch more. Maybe after enough of those even I can learn more about batteries and eletricity. :D

[@knurlgnar24]

If the batteries are full charged but reading low on your hydrometer then they are likely sulfated. Depending on the battery cell size and type you may need something more like a 10A supply and they may vent a lot during desulfation, so be ready for that and make sure they don't run low on electrolyte. There are safety concerns working with large flooded batteries but a lab supply of sufficient amperage will work on them just the same as a smaller battery. Assuming you have a lead-antimony battery bank a 5A supply probably isn't enough for a forklift battery/cell.

[@pasiturpeinen9273]

@@knurlgnar24 Hi, Thank you for fast reply. I was not expecting such a rapid responce. Yes, that hydrometer reading was after charging batteries. I have forklift battery charger which should be original. there are lights, which indicate cell charge from 2.1 to 2.65. While charging reading was highest at 2.52. immediatly after charging 2.3 and it is dropping slowly to 2.08 ( few days after charge) I´m keeping eye on eletrolyte levels and I also have fume extractor available. Do you have safety concerns beyond hydrogen build up? Those seems to be 500 Ah cells so most likely lab power supply is not right one for the job. Since all 12 cells are quite same condition maybe I can recondition battery with original charger? Just enough charge and drain -cycles? Thank you alredy in andvance for any help you can provide.

[@markjones5580]

Would you follow similar steps to recovery larger 6 volt batteries that are rated over 100 amp/ hr. ? Would you use a power supply with higher amperage?

[@knurlgnar24]

Yes, this exact same method will work on a 6 volt battery. A power supply like this would be sufficient for a 100Ah battery and I have used them on my bank of 100Ah 12V batteries.

[@AmrHollywood]

I was under the understanding that with an AGM, if the over voltage causes any bubbles in the mat, the gas will get trapped, arc and burn that cell and lose capacity? I have seen that de-sulfating / maintenance charging flooded lead-acid it is very normal for bubbles, even during normal charging they out-gas.

[@knurlgnar24]

AGM batteries bubble just like flooded lead acid except that the bubbles are slowed down by the fiberglass mesh. The idea is that they are slowed down enough so that the hydrogen and oxygen recombine into water before escaping out the top of the cell. Overcharging doesn't cause issues unique to AGM batteries aside from pressure which could deform or rupture the case if the bubbling is violent enough, or more likely simple dry-out due to electrolyte loss.

[@thedavesofourlives1]

sitting that long should self discharge to something like 12.5 - 12.6 . Above 12.7 means your cells are starting to dry out and the acid is getting stronger concentration, time to open it up and squirt some distilled into the cells (5-10mL). Wait a couple days and recharge, and should settle after a day to something in the 12.6 to 12.7 range.

[@knurlgnar24]

A battery that settles to 12.7V after a few days is a damaged battery (lead antimony chemistry excluded). Any good battery should stay above 13V for a long time - usually months. I do agree that this battery may have lost some water.

[@nowthenad3286]

That was a brilliant couple of videos. I am amazed that you are bothering to excuse yourself for spending time repairing a sulphated battery. Was that in case someone had mistaken this for a video of Lionel Messi's greatest goals?

[@knurlgnar24]

I have other videos of similar content and one of the most common comment subjects is questioning why I'm such an idiot to waste my time and electricity on desulfating a battery when everyone knows magic device X does it overnight, or magic additive Y fixes it, or buying a new battery is cheaper than the electricity needed to desulfate it or... Sometimes it's worth a few mentions to avoid such inane comments. This video thus far has avoided them fortunately! Thanks for the compliment Nowthen.

[@L.V-Rider]

If you do the discharge test directly after the full charge it use some of the surface charge. It should sit about 2 hours before the discharge test so that surface charge dissipates.

[@knurlgnar24]

The surface charge certainly contributed but it would only affect such a test by a few percent. Now years after this experiment when I look back it's pretty clear that battery temperature was the only significant factor. I was thinking of covering this in a new video at some point.

[@rodcleve]

@@knurlgnar24 Was the temp factor good or bad?

[@surgingcircuits6955]

Would you change the procedure or voltage marks for deep-cycle vs typical auto batteries? Thx for the vids.

[@knurlgnar24]

Same for both types.

[@surgingcircuits6955]

@@knurlgnar24 , would you discharge lower than 11VDC on the deep-cycle batts?

[@Itisme38]

If you had a 100ah batt what voltage and amp would you use and if u could guess how long would you run it to being back capacity.

[@AerialLensVideo]

Thanks for both Part 1 and Part 2 -- Well done! Here is my dumb question: Can that little power supply work on a dead car battery (one that has been sitting a couple of years)? I realize there are small "automatic" chargers offered for the purpose of restoring and charging car batteries, BUT I would also like a budget priced DC power supply and cannot afford both devices. Thanks!

[@knurlgnar24]

Yes, a power supply like this will work well on a sulfated car battery and I have used it for exactly that purpose in the past. It will not have the safety features like overcharge protection and such so keep that in mind, but that is also the reason why nearly all purpose built battery chargers cannot recover sulfated batteries even if they claim to be able to. I obviously wouldn't recommend doing this indoors like I am here, but it's much easier to record that way.

[@AerialLensVideo]

@@knurlgnar24 Excellent, thank you. I would presume then that the power supply method would take much longer and, as you suggest, would require monitoring every half day or so for an old "dead" (and vented) 12v car lead acid battery, right?

[@johnjrgensen701]

Really good info here. One question; I learnt that if you discharge under 12,0v (no load) or 12,2v (under load) youll cycle your battery too deep. Would your tests be as valuable if discharge was stoppet at 12 volt? Regards, John

[@knurlgnar24]

The purpose of cycling is to mechanically stress the plates so it would be better to deep cycle it, but you don't have to. As for the discharge tests a deeper discharge gives more information about the battery health but again one doesn't have to deep cycle the battery to test capacity so long as the more limited information is acceptable.

[@johnjrgensen701]

@@knurlgnar24 Thanks. This is good info!

[@gonzo_pix]

I practice the method you showed on 12V, 7 Ah, AGM batteries. Some of them could be reactivated without problems, but currently I have one on the charger where one cell has inflated noticeably. Is this then a "dead cell" as described by you? Or does it still make sense to continue charging with lower voltage and observe? My question is based on the assumption that a large sealed AGM battery would then behave similarly.

[@knurlgnar24]

If the battery is deformed I would definitely not mess with that battery for both safety reasons and because I don't see much hope for success. This process only remedies sulfation damage so anything else that might be wrong will still be wrong. Yes, a battery of any size will behave similarly.

[@gonzo_pix]

@@knurlgnar24 I must correct myself. The deformation of the battery occurred during charging. Before that, it actually looked like new. The battery looks like the Leoch from your video - it has no valve to let gas escape. So for the record - if it inflates, it's probably dead and you should stay away, right? What an amazing parallel to dead animals on the side of the road - in the middle of summer 😅

[@brettschacher8644]

Well after hearing the price of those orange batteries, I would think that would be a good time to start looking at LiFePo4's as replacements.

[@starlord8200]

So can i use regular charger and lab only for fast charge?

[@garbleduser]

I would like to know the internal resistance delta for each reconditioning cycle. What does your conductance tester say about it?

[@knurlgnar24]

I was going to use my conductance meter but the video was getting so long I omitted it. Now I wish I hadn't.

[@garbleduser]

@@knurlgnar24 Well, just post a final reading here. (24 hours after full charge)

[@marvinsalee7134]

Did you add any water to the big batteries? There is a way to add to the glass matts. Awesome informative video thanks.

[@knurlgnar24]

I did not and yes water can be added to the glass matts. I don't recommend this for various reasons but if the cells are low on electrolyte then adding water will help.

[@marvinsalee7134]

@@knurlgnar24 I understand the not recommending it on here. I have several full river agms I've been using in a off grid solar system for about 8 years. I've brought back several Small inexpensive AGMs by either adding water to the matt or pulse charging but I don't have those awesome toys you have for checking the ah and such. I wonder if the cycle life the factory puts out is the actual lifespan or if by desulfating and adding electrolyte can get far more life from them. What you say to this question? Awesome videos BTW.

[@derekmarshall2169]

I watch another channel as well by John Daniel and he uses 3-phase wind turbines to charge his batteries and he says his batteries last longer and dont sulphate as quickly compared to a steady DC voltage.. He uses a 3 phase rectifier feeding the batteries directly with a dump style charge controller to prevent over voltage conditions destroying the batteries. I wonder if that pulsating rectified AC doesnt do a better job of knocking off the sulphation than a constant DC voltage. What are your thoughts regarding this?

[@knurlgnar24]

I think he's likely just equalizing them more adequately with that setup. A lot of deep cycle batteries end up sulfated due to lack of adequate equalization. e.g. most inverters do not allow a high enough input voltage to properly equalize flooded lead antimony batteries so almost no chargers have a setting that risks inverter problems, and therefore doesn't properly maintain them. Even those AGM batteries I have are supposed to be equalized twice a month. No one does that - except maybe John! That's my theory anyway without knowing much about his particular circumstances.

[@derekmarshall2169]

Thanks, so a steady DC versus a pulsating rectified AC doesnt make a difference to the sulphation but rather it is the higher voltage of the equalisation that gets the job done.

[@Nameless.v2]

Please , can you tell me what is the cut-off current for battery charging : Ex : for lead acid 12V 7.2A

[@rayshaffer2727]

I saw you mentioned in a previous reply that you could use this for larger 6V deep cycle batteries. Is there a different power supply or charger you would recommend? I feel like a single battery at a time will take forever. Thoughts? Some context, I use 100s of golf cart batteries a year in remote solar equipment installs.

[@knurlgnar24]

A good lab power supply should work well for you. I have a review of a Wanptek out there that I think would work great for your application. (they sell different voltage/current combinations) You can connect multiple batteries in series for the desulfation step as long as you're careful about it (voltage will be different on each battery). Or you can connect them in parallel and bump up the amperage. Either way has its advantages/disadvantages but regardless a series/parallel combination should be much faster than single batteries. That said have you considered simplifying your setup and just buying cheap power supplies and doing 1 at a time? $500 should get you 10 lab power supplies allowing full control of 10 batteries at once. Just a thought.

[@rayshaffer2727]

@@knurlgnar24 Thank you for your response. I will take a look at the low cost power supplies you mention. That may actually be better. At first I thought if I could find a 48V 100A power supply or dumb charger it would be most economical.

[@knurlgnar24]

@@rayshaffer2727 I would recommend staying away from a 48V 100A power supply for various reasons. If you want a larger power supply you could take a look at the wanptek brand on Aliexpress that has worked great for me. Just search for it. They have a 15V 50A version for under $200 that may fit your needs well for 6V batteries. Personally I'd get a 30V version so you can also use it with 12V batteries but I don't know your exact situation.

[@forsfullcommunications1561]

Greetings, during the sulfation process, do the residues fall to the bottom of the battery or simply disappear by virtue of Epson Salt dissolves? If it falls to the bottom is it important to get rid of it for the best functionality of the battery itself?

[@knurlgnar24]

Most of the lead sulfate is retained by the plates and stays in place, but some plate shedding does occur whenever a sulfated battery is recharged. All flooded batteries are designed with plates that have empty space at the bottom of the cells to allow this shedded material to collect without shorting out the active plates. Longer life batteries have more space than shorter life ones, but they all have this feature to some extent. For most people I take the stance that it's best to just let the shedded plate material settle to the bottom and not worry about it. Industrial battery restoration companies do flush that material out before selling them as used batteries but as this requires disposing of lead contaminated acid and reintroducing pure acid in the proper concentrations I just don't see it being practical for the typical individual.

[@carolinafirewood]

Cycling the battery obviously is important in the desulfation process, but I don't want to spend $500 for a DC load. Did you mention something about running a inverter with a load (light bulbs for instance) as a way to discharge the battery before recharging again. What would be considered a reliable, steady current load for this project? Thanks!

[@knurlgnar24]

The ideal load level depends on the battery size but really your patience is the limit. Any load will work. Put it in your car and turn on the headlights, find a 12V appliance and connect it to the battery, etc. An electronic load is a luxury. I think everyone should have a cheap 12V to 120V inverter for emergency situations so that's what I'd suggest. Even a $20 one would charge your phone, run your laptop, run LED lights, let you watch TV with physical media, etc and be pretty useful for power outages, camping, traveling, etc.

[@kia1185]

very good.

[@JR-yl8qi]

Oh knurlgnar, we missed thee.

[@scruff7559]

ABYC is making the neg yellow to eliminate potentially harmfully confusing the DC neg with the American AC live. They are both black on a lottov boats.

[@knurlgnar24]

Yes, the wire color convention for DC is not consistent. Is Black hot or is Black neg/gnd? What is white? Black is ground/neg on battery systems so white must be positive/hot? No, wait, white is neutral. No? ???

[@ProdigalPorcupine]

@@knurlgnar24 - For our rings here in the U.K. we use brown = live, blue = neutral and green/yellow stripes for earth.. We used red = live, black = neutral (earth y/g) until a few years ago. That could lead to an interesting situation for a Brit emigrating to N.A. who decides to do any electrical work!

[@scruff7559]

It's a lot more straight forward in Europe. Single-phase 230V, 3 phase 400V, unique colours, you guys are nuts. I'm over here; www.fieldlines.com/index.php/topic,150161.0.html I do pretty similar work to yourself. Kind regards, Liam.

[@formless7068]

Hello! I have a question if you don't mind. You state during cycling that you're pleased with the results because you are coming so close to, and even exceeding, the ~3.5 Ah that the battery is rated at when brand new. Isn't the battery rated at 7.2 Ah, thus the 1C discharge at 7.2 amps? Is this just because the capacity is reduced at such a high discharge rate of 1C?

[@knurlgnar24]

At some point in the video I show the graph in the datasheet that depicts Ah vs discharge rate. The Ah rating of the battery is at a slow discharge rate to give it a large number for marketing purposes whereas I used a very high discharge rate due to my own impatience. In short, yes, Ah capacity is reduced at high discharge rates. The total amount of Ah available is unchanged but the remaining capacity is only available at lower amp rates.

[@formless7068]

@@knurlgnar24 Thank you!

[@tekdragon]

damn that is a sweet electronic load, even if its a Rigol! watching a realtime battery discharge curve is downright pornographic :D I understand that a desulfated battery will never perform like a new one, but I was wondering, even if you can get it back up to its rated capacity, how easy is it for to regress? in my experience, recovered batteries dont stay in good condition long if you slip up in your cycle maintainence. they always seem on the verge of losing all of their hard-won capacity again. enjoyed the videos!

[@knurlgnar24]

That depends on the overall condition of the battery. If a battery was neglected and just sat unused then you will have a long service life after desulfation in most cases. If it was in use and got positive plate corrosion, buckling plates, water loss, etc then your results won't be as good.

[@tekdragon]

@@knurlgnar24 interesting! so it depends on WHY it became sulfated in the first place. btw you mentioned the idea of doing a video on how to PROPERLY maintain/store a battery. i'd love to see a video about that and why a float charger isnt enough etc

[@CollinBaillie]

What voltage did you use for the boost charge on the 100Ah batteries?

[@knurlgnar24]

I did quite a bit of experimentation and variation but high 14V for long periods of time or low 15V for short periods of time were typical. Above 15V you will lose water fairly quickly. Patience is usually better if you have the time.

[@gonzo_pix]

What if the battery takes charge but then discharges itself over the course of a few days? Internal short circuit between the plates, or a problem with the filling / chemistry? Is there anything that can be done to save the battery in this case, or is it time for the scrap yard?

[@knurlgnar24]

Sulfated batteries often appear to discharge somewhat before stabilizing at a non-full charge when sitting due to chemical factors, but assuming you have a battery that truly discharges then in my opinion it should be scrapped. You have either a plate separator defect allowing a cell to discharge directly, or contamination in a cell electrolyte. Either way I consider that beyond the scope a homeowner can do without a lot more work, risk, expense, and effort. I always scrap batteries with cell shorts. Even if it is only electrolyte contamination that contamination likely permanently altered the plates themselves. Epsom salt is a common contaminant nowadays given all the videos out there on it. Once added to a battery it is permanently damaged.

[@gonzo_pix]

@@knurlgnar24 Ok, then I guess I will stop my efforts in that case. The battery has been sitting in my basement for a few years. Salt was not involved, but maybe it was a mistake to fill the battery with supposedly distilled water from the dryer.

[@pablopicasso8502]

Hi, Ive got a quick question to you about desulfating regular truck 12v batteries. In my case I have 12v battery, group 31, 80ah, 730CCA. 1. What current/voltage/time should I charge it with initially to "wake it up"? 2. Voltage/current for cycle charge? (10% of Ah I heard, so 8A?) 3. Wattage/Amperage for cycle discharge? Also, is it the same for dual purpose batteries? There are no specs on truck batteries and I cant find these online.... Thank you

[@knurlgnar24]

I'd suggest making sure the water level is above the plates and using 2-5A of forced current at whatever voltage that results in making sure the batteries do not gas too violently or overheat. Every 12-24hrs after stabilization you can do a discharge cycle. If your batteries are 'worn out' and not sulfated you'll likely not find much benefit but if sulfation is the issue they should recover to some degree.

[@pablopicasso8502]

@@knurlgnar24 ok, whats the best discharge wattage for 80ah 12v battery you think?

[@robklein583]

I would like to use this method on a badly sulphated battery from my car which sat most of the summer. 70Ah AGM battery. I read that AGM batteries need slightly more voltage to charge properly than supplied by common chargers. My old charger goes up to 14.4v but apparently AGM batteries charge at 14.6 to 14.8v to achieve full charge and desulphate. What voltage and current would you suggest to use on the Korag and for how long.Thx.

[@knurlgnar24]

If the battery sat uncharged over the summer it can be saved almost for certain. AGM does not require more voltage than flooded batteries - the voltage required is related to the chemistry which is generally grouped into three loose categories: Pure lead, lead calcium, and lead antimony. I don't know your battery but it is likely lead calcium which is the same chemistry as nearly all flooded car SLI batteries today in the USA. It depends on how much time you have but around 14.6 to 14.8V is a good voltage for these as you stated. I'd actually suggest 15V for a flooded battery as the water can be replaced. I don't know your exact situation but I'm thinking 14.5V would be a good start point with 12hr 14.5V desulfation durations after full charge each cycle to avoid too much water loss. Each discharge cycle would then involve charging normally followed by another 12hr 14.5V desulfation. If your battery takes little to no current you can safely start at as high a voltage as you want and limit the current to an amp or two to get the process started until you get that 1st charge done. When cycling if the battery is stubborn you may need more than 14.5V, but much above 15V and you're likely to lose a good amount of water and shorten battery life. It depends a bit on your patience and available time commitment. There's nothing wrong with leaving it on a charger for weeks at a time at something in the low 14V range too. That's a completely acceptable method if you have the time.

[@robklein583]

@@knurlgnar24 Thx. It's very nice you answer so quickly. Cheers!

[@noahriding5780]

When you desulfate a battery, and it works, ... how long does that buy you typically before its back at the same level of desulfation? I'm curious to ask this to figure out how long a desultation job is going to last and how often to do, particularly for large amp hour batteries. Thanks.

[@knurlgnar24]

It depends on how healthy the battery is otherwise. Some last only a few months, others last for over a decade. If your battery was 'new' and just sat on a shelf then you'll likely get nearly the full lifespan out of it. If it was heavily used and then got sulfated then it's probably not going to last very long.

[@knurlgnar24]

I also should mention that desulfation only helps sulfated batteries. This is obvious but often overlooked. If the battery has other issues then this procedure isn't going to help matters. Batteries age and degrade over time and use and nothing short of recycling them can bring them back to a useful state at that point. A good number of batteries go to the recycler that are simply sulfated though and that's a shame.

[@noahriding5780]

Thank you for the wonderful advise and help. @@knurlgnar24

[@nathanchalecki4842]

This guy gives off a slight Lock Picking Lawyer curve

[@knurlgnar24]

That's quite a compliment. I love his videos!

[@youreaknob]

Why did you stop the load test at 10.5v? With the 1v drop across the cables you should have discharged down to 8.5v which would have been 9.5v at the battery. Or am I missing something?

[@knurlgnar24]

You're not missing anything. The situation is that discharging to 8.5V would have made very little difference vs 10.5V.

[@quentinbush]

Acquired a 180Ah 12v lorry battery, its been stood for 2 years and appears sulphated?. Meter reading was 11.4v. I emptied it and refilled it with Manganese Sulphate and put it on charge, its voltage recovered up to 14.2v but it quickly dropped, still doesn't hold a charge. Looking inside the plates look black between the separators. There is much bubbling going on inside. Q. Do these desulphation gadget things for sale on eBay actually work or are they gimmicks? Question: Should it be emptied of this Manganese Sulphate solution and refilled with battery acid or distilled water before recharging or just scrapping it? Thank you.

[@knurlgnar24]

The only chemical that should be in a lead acid battery's electrolyte is sulfuric acid and water. Since it is now contaminated with manganese you could try emptying the electrolyte, replacing with pure water, and charging until sg stabilizes. Then empty and replace with the proper concentration of sulfuric acid and water. Once contaminated with other chemicals side reactions change the chemistry of the battery so your odds of restoring the battery are lowered. The desulfation gadgets are gimmicks, though some of them desulfate with standard methods and function even though they advertise some other floofy marketing just to be able to get more sales. Are you sure it wasn't magnesium sulfate? That would be more common. Same answer either way though.

[@keithlucas6260]

As a chemist, once I saw videos recommending MgSo4 to "fix" a lead/acid based battery system, it was like watching "amateur hour" live. Both metals have different densities and electrolytic properties in the presence of an acid. I even remember this equation on a midterm test, so it's a nobrainer. I personally have a nice lab benchtop power supply that has variable volts (pressure), amps (current), and watts (power). I also have a NOCO Genius 10 just to charge my Harley battery which is a LiPo, and it has the 12v "fix" mode which is what I used on one dead battery with success. With flooded batteries you can use a hydrometer to check specific gravity, however with agm you cannot access the gel without drilling holes or removing the top which is beyond the homeowners capability or safety. I've seen the videos of guys using 200 amp welders to temp shock batteries and kinda chuckle because most of us "on the farm" have at least three or four of them and would rather use our "stupid" charger with jump start...plus they have timers on them for safety. If you want a 5,000 cycle 10 year battery that you can drain to zero each time then spend $800 ish on a LiFePo4 battery. Heck I fly R/C aircraft and have LiPo's that are 10 years old and still going, and they're from $7 to about $250 bucks. Good luck.

[@quentinbush]

@@keithlucas6260 Thank you for the time and your valued opinion. I know what you mean about lido's, some used correctly can live for years. I had one of the very first analogue mobile phones and after charging it up after many years, it held its charge as if it was new.

[@ShadowGKCP]

Do batteries that have been desulfated re-sulfate faster than new batteries? I'm thinking of refurbishing my dead UPS battery, for fun but also to use it, but if it re-sulfates much faster than a new battery then I kinda don't wanna deal with it.

[@knurlgnar24]

Sulfated batteries will always have some permanent damage as a result of the abuse they sustained but any used battery will have some level of damage just from being used. Previously sulfated batteries that are desulfated will not re-sulfate faster than any other battery. Some people claim the sulfate crystals are nucleation points for new sulfation but I've not seen that borne out in any real world applications I've come across. Just take care of them like you would any other battery and they'll give you good service.

[@ShadowGKCP]

@@knurlgnar24 Alright awesome thanks for your reply

[@NeilBooth]

Are you sure you can't top up old agms??? I think you can? Just pop the thing in the middle and the seals should be under

[@TURSTY09]

Hey thanks for the great vid. I have a noob question. You always hear that discharging AGM's below 50% can damage them, yet this process looks to be discharging them well below that intentionally over and over again. Is it just that the high voltage charge does more desulfation then the discharge sulfates them? Meaning that every cycle is an improvement?

[@knurlgnar24]

Not a noob question, this is something so-called experts often get wrong. It is not on any lead acid battery AGM included damaging to discharge below 50% DOD. If you look at documented cycle life vs discharge curves from any major manufacturer the data shows that the battery only cares about the product of the discharge depth and cycle count. 40% discharge twice is about the same amount of damage as 80% discharge once. Once you get down to 10% to 20% or so damage starts accelerating somewhat but that isn't a useful SOC range anyway so it's irrelevant. You can safely discharge any lead acid battery down to nearly 100% discharged as long as you recharge it soon after. You'll get fewer cycles out of it vs only discharging half that much, but the total energy stored/provided will be close to the same.

[@TURSTY09]

@@knurlgnar24 Thanks for the reply! Thats good info to know and makes a bunch more sense than the 50% rule quoted so often. I have one more question as I sit here watching my lab power supply try to charge a 225AH 6V battery after a load test (got 175AH from it). My power supply is a cheap one and can only do 10A. When the battery is really low after a load test, I take it it's fine for the power supply to only output 5.7 volts for the first hour or so as the state of charge comes up (as resistance climbs), then I would expect to see it increase up to the 7.2v I'm looking for before the amps start to fall away? Does this mean all the de-sulfation is happening after the battery has reached a higher state of charge and the voltage picks up? ......meaning maybe half cycling the battery is a slightly faster way to get a few cycles through it? Or is something still happening down at the 5-6 volt range? (ok maybe a few questions)

[@kal9906]

@@TURSTY09 It is bulk mode charging at first, taking the 10A max of the power supply while the voltage is limited to the discharged battery voltage. As the state of charge increases to the 7.2V absorption voltage, the current drops as the voltage reaches 7.2V Once the current stabilizes, increase the voltage to 7.75V for an equalize charge for approximately 3 hours or so. Equalize charge is where most of the de-sulfation happens. This is why a variable power supply is so useful for this.... regular chargers are designed to chronically under charge batteries to err on the side of not boiling the electrolyte dry.

[@TURSTY09]

@@kal9906 Thanks Kal, thats what I assumed. I have successfully manage to get 4 225AH 6v batteries from around the 150AH mark after an un-intended complete discharge and rest for ~4 weeks, back up to a reasonably healthy 210AH and returned them to service. They each took around 8 cycles. It was super cool to put this learning to practice and leave me with thousands of dollars of usable batteries that were going in the bin (well the recycle center) otherwise! All with about $300 worth of kit.

[@jasonbrown467]

@@knurlgnar24 i have been studying lead acid batteries as a hobby for about 2 years and you might be the second person i have seen make those claims and i agree with every point you made. some times i feel like a conspiracy theorist, because it seems like i dont trust anything i am told, and must see it for my self before i start to believe it. my own research and tests, and of course data sheets from manufactures had lead me to my conclusions. if i listened to all the wisdom on batteries i would have never touched them, because "they can become bombs" etc etc, let alone understand them, which i find to also be a narrative that seems to benefit those that make or sell them rather than those that use them. btw, i have come across your videos many times over the past several years, before i even thought i myself would deep dive into this topic. appreciate you staying the course and sharing your findings.