2 Ways Lithium KILLS Your Alternator (and how to prevent it)

In this week's video, I answer the question "Is my alternator safe with LiFePO4 batteries?" The answer is... it isn't-unless you take precautions.
In this video, I refer to a thermal switch I bought. It was a 10-amp, normally-closed thermal switch. I chose one rated for shutdown at 110-degrees C. That temperature is something you should choose yourself, but I think that is a good number for a thermo-switch mounted inside the alternator case.
In preparing for this video I searched eBay again and found a better choice. This is the same basic thing, but this one is rated for 16a. That would be more then plenty for any alternator I've seen. Also, it's CHEAPER!
www.ebay.com/i...
A commenter brought up a concern (thanks Apollo). He thought that the thermal switch might suffer from the back emf of the coil being disconnected when things overheat. He might be right though I have seen this done in motors before. Either way a simple "flyback diode" (Google it) might give extra protection and is cheap and easy to install.
Another thing that I wish I had talked about in this video was engine room ventilation. It seems basic but keep it cooler around your alternator and your alternator will run cooler!
Well as I say the description section is how I reserve the right to get smarter.
If you would like to learn more about the BankManager or order one, check out:
www.emilyandcl...
Here is a link to the video where I talk about engine belt upgrade • Boat DIESEL ENGINE Hac...
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[@bearchow1929]

I'm a highly accomplished electronic engineer in several things including power management systems and devices used in alternators and battery management systems. I passed by your video thinking "what is this non sense". I was quite surprised to find that you are quite technically correct in this video. Excellent job.

[@pieterbezuidenhout2741]

It's the years experience that sometimes counts more than the Qualifications 😁.

[@davelee7572]

why not just run a 4x4 relay dual battery VSR? if the bms cuts out the lead acid battery will still be there.

[@Clarks-Adventure]

Because the lithium gets mischarged by the alternator.

[@davelee7572]

@@Clarks-Adventure mischarged how? "Lithium Ion batteries are charged with an absorption voltage of 14.25 V"

[@Clarks-Adventure]

They shouldn't be. I suggest you read Conrad's writeup linked to the bottom of this. www.emilyandclarksadventure.com/bbms

[@jgatkinson744]

I remember when alternators first come out I was working for the Ford company on the coast of Mississippi. They sent us to auto school in New Orleans and they explain the function of the alternator they were going to replace the generator on cars and they replace them were the last cars, we had that had generators 1960 alternators took their place the fields turned inside the armature right reversed to what a generator did and you had to have 1 1/2 volt to excite them to make them work. If you had a dead battery you could push that car all day long and it would never generate any power that was a long time ago we have come along way now with electronics . Grate job Clark as always

[@Clarks-Adventure]

Thanks

[@CruisingMaya]

Thanks for the great breakdown, Clark! I'm a marine electrician and have hesitated to do lithium installs on my customers' boats because of the off chance that a BMS opens the circuit, frying the alternator and everything else. I REALLY like that the lead battery is there as a guardian.... and now with ways to thermally protect even internally regulated alternators I'm even more excited. I'm currently cruising, but will be back to work in a few months. I look forward to the next video and the possibility of installing a bank manager. Thanks again for the great video and sharing your knowledge!

[@nordic5490]

No chance that a soft start 50A BMS can fry the alternator when a 90A compressor, or a 200A winch with ugly back emf, doesnt. The starter battery has very low impedence and is the voltage clamp, in much the same way as a giant zener diode

[@Clarks-Adventure]

@maya. Have you gotten back yet? Did you find an opportunity to do a BankManager install?

[@darrellobrien4416]

would a flyback diode work with the lithium battery BMS shutting down?

[@Clarks-Adventure]

@@darrellobrien4416 nope. It's not a reversed colapsing field. It's just the alternator making full power. Forward and too strong for a diode anyway.

[@CruisingMaya]

@EmilyAndClark almost had a customer convinced to get a lithium bank and keep the existing lead acid. They didn't go for it though...

[@michaelm6682]

The way the author of this channel explains and teaches reminds me of my enthusiasm for science as a youngster in class (late 70s-early 80s). I’ve had deafness since birth, and what little I could understand verbally was supplemented by visuals in the classroom. The author has many of the qualities of those teachers I admire and I appreciate that very much. Thank you so much. As an adult, with my deafness, KZbin, with its closed captioning, has made the educational aspects much more accessible thank goodness. With the help of YT, I’m attempting to design & build a 100ah lipo battery system for my truck with limited space. I’ve purchased a Renogy 12V 30A DC to DC Charger with MPPT, On-Board Battery Charger. At the moment, after learning from this video, It’s clear that I need a system that is plug and play. I don’t have the capacity to understand all the science at play here. I use my truck daily as part of my job doing outreach and reliability and safety is my utmost concern. As well as affordability, which is why I’m trying to design and build it myself. I just wish there was a complete system I could install myself with more confidence in those goals. Any suggestions? Thanks for “hearing” me explain my situation in advance. Kind regards.

[@Clarks-Adventure]

You might find this useful. www.emilyandclarksadventure.com/bbms

[@Tron-Jockey]

For an extremely down and dirty (cheap) fix you could try putting a BZY91C18 (18V nominal) Stud Mount Zener Diode across the output (DC side) of the alternator. It's rated at 100W Steady State Power and 5000W Peak Pulse Power. They're about $20. Voltage will never go above 19V. Might want to include a current limiting resistor as well.

[@rylanbrowne5658]

Spot on. I was thinking a decent capacitor ocross the battery input

[@Clarks-Adventure]

Caps can cause other issues. Be careful.

[@Clarks-Adventure]

Because I'm pretty sure it will melt. But you are free to try on your boat.

[@ar5000]

How about adding a metal oxide varistor?

[@Clarks-Adventure]

Have you seen one that can handle 2kw?

[@jimb348]

Great information as usual. Your deep understanding of electrical engineering and excellent explanations are what make your technical videos so great. Often other channels, even when providing technical details, are just repeating what they were told by equipment manufacturers. Which is not all bad or wrong, just sometimes not quite all the details that we really need to understand all the issues and make the best decisions. I am looking forward to the alternator tear down. I have often seen people say that you should basically throw away an alternator if you blow the diodes and that has always seemed like it shouldn't be that hard to fix. Thanks for all the great videos. I don't even own a boat yet and may not for several more years, but I'm tempted to buy a BBMS just in case you quit making them. So please give advanced notice if you every decide to quit. But hopefully you will be hugely successful with it and keep making them.

[@Clarks-Adventure]

So nice of you to say Jim. As for fixing alternators, that could be true based on the cost of US labor. And because of that culture parts are hard to find. Go someplace like the DR or Mexico and everything is fixed. So parts are readily available.

[@neilfromclearwaterfl81]

@@Clarks-Adventure The Alternator parts are all pretty easy to find, at least here in the area around Tampa Bay. Alternator Starter Parts Wholesale in Port Richey Florida is a great resource for (as you might have guessed) alternator and starter parts since the owner is quite passionate about not only having the parts but also the quality of the parts. They recently got me an American Made higher quality long nose starter drive than most put into a rebuilt Marine 454 inboard and got it overnight for pickup at no additional charge. Had a nice motorcycle ride on a beautiful Florida day when I went to pick it up and was able to look a person in the eye and shake a hand. Hopefully his son will continue running the enterprise when he retires. How many folks throw out small appliances just because its cheaper to say replace a $125 portable ice maker because it costs too much to pay someone to put 3 drops of sewing machine oil on the bearings of the computer fan that was used on the condenser. We often don't think of the cost of waste on the environment when we do that and only look at the Dollars and Cents or whatever currency you dealing with. I just fixed a small appliance by taking the 15 minutes to oil the computer fan inside it instead of throwing it away and dropping $125 on a new one. That was like getting paid at a $500 an hour payrate for 15 minutes of work plus it took less time than it would have to purchase a replacement, unbox it, etc, etc along with dispose of the old one. Perhaps we should have a moment of silence for the demise of all the Emmet's and their Fix-It Shops (remember Mayberry) across the country who've fallen victim to the disposable culture we live in. Keep up the good work but don't keep working so hard at it that you don't have enough time to pause and do the simple things like comb your hair. ;> I technically gave you three likes on this one but the counter sadly only accepted the first one. Best!!!

[@Tron-Jockey]

For an extremely down and dirty (cheap) fix you could try putting a BZY91C18 (18V nominal) Stud Mount Zener Diode across the output (DC side) of the alternator. It's rated at 100W Steady State Power and 5000W Peak Pulse Power. They're about $20. Voltage will never go above 19V. Might want to include a current limiting resistor as well.

[@mikehill3764]

The service manager at the marine mechanic facility I use just talked me out of using a lifepo4 battery for my starting motor. He was worried about how the charging system would be affected on my mercury pro xs. Told me to stick with agm and that’s exactly what I plan to do. Nice video. Very informative.

[@Clarks-Adventure]

I agree. Use lead for starting. If you want to add more battery you can add li in parallel with a BankManager

[@MrZeissOne]

Thanks Clark. I'm finding you far more straightforward and informative than the battery manufacturers. Q: If I go either the dc-dc or Battery Bank route, d o I need to install a monitor or alarm/fuseto let me know if it fails? Or, is my first indication smoked alt diodes. I sent an inquiry to LiTime, asking if they are recommending any sort of dc regulator. So far, no response. And I'm finding lithium battery ads pushing their products as "drop in replacements" for lead acid batteries. The alternator is a convenient back-up for cloudy days, so I would really like to retain it as a charging source. However, I've just done an alternator replacement. It was not fun, easy, or cheap, and I'm not looking forward to doing it again soon. Thanks again for this video. It's a valuable service for any of us who go lithium! 4:56

[@Clarks-Adventure]

Li is nowhere close to a drop in replacement for Pb. Even the li charger controllers available today don't charge it right for a long life. To keep your alternator cool the best solution is an external regulator with a temperature sensor. I've always used Balmar. People I respect like Sterling. BankManager and some lead will keep your alternator's diodes safe and charge your Li property for a long life. (So there's my commercial. ) www.emilyandclarksadventure.com/bbms I'm not a fan of DCDC chargers. I think I go into it in the FAQs in the link above

[@CampPrevost]

I use the Sterling Alternator Protection device $80 bucks specifically made for an alternator dump.

[@chiraldude]

For protection from sudden BMS shutdown, why not use a zener diode shunt? A zener diode is non-conductive until the threshold voltage is reached. Then it becomes a near open circuit. If you were to put a zener between the positive and negative charge wires, the voltage spike would be limited. Since the voltage spike would only last a few hundred milliseconds, the zener would be able to dissipate the excess energy with no problem. The alternator regulator will respond and bring the voltage back to normal and the zener shunt will turn off. I did a quick search and found 50W 50V and a 50W 35V zener diodes for around $10.

[@Clarks-Adventure]

I've tried a zener in the past. It blew like a fuse. I don't remember the specs. Maybe there are better ones now. It's going to have to dissipate 35vx140a, that's like 5kw. That's a lot of power. The time wouldn't be the 400ms. That's how long before the alternator diodes fry and the zener it trying to protect those. It's going to be until the regulator shuts down and then the time it takes for the rotor field to dissipate. If you run the test tell me how it goes. I don't want to risk my alternator.

[@teardowndan5364]

An alternator under full load can be putting out 200+A for a few ms after the load disappears, your 50W zener will be taking 2000+W during that time. You need something more robust to take the spike. A 15V zener driving the gates of a dozen 250W MOSFETs to spread the heat and 5W 0.1 ohm balance resistors between each source and negative rail might work for clamping surges to about 18V. (15V zener + 10A x 0.1 ohm + 2V of gate drive for logic-compatible FETs = 18V) Since the name of the game is slowing down the voltage spike so the regulator can react before voltage gets out of hand, a 500 000uF 25V capacitor bank could also do the trick.

[@DrJuan-ev8lu]

You could probably put a super capacitor across the alternator to absorb the spike.

[@dannyjensen4954]

Great Lithium topic. If you have a Balmar with an expensive external voltage regulator, you can rig a switch that allows 50% output. You can run in 50% mode by default unless you want to "fast charge". Fast charging is used on exception and prolongs the wear on the water pump pully on my Yanmar 3GM30f motor.

[@benkanobe7500]

Your flat (most times installed serpentine) belt also has substantially more surface area compared to a typical "V-Belt" so it wears out much more slowly. Also, a flat belt usually has a spring tensioned self-adjusting pulley that is easy to adjust tension for belt removal and replacement unlike a fixed position pulley on V-Belts which require more tools and frequent adjustment.

[@Clarks-Adventure]

So much better!!

[@stephencox4224]

@@Clarks-Adventure Not always I have pulled down many engines and found that the amount of tension applied by serpentine belts shows wear on the front upper main bearing shell at about 11 o clock which shows they often have too much tension applied in the design stage, So not everything is all apples in every case

[@HitTheDirt]

Worked in power when many were new. This is also a great video for anyone thinking of building an off grid hybrid solar/mechanical system.

[@Clarks-Adventure]

Thanks

[@BigDreamsBoating]

I love the content you guys are creating. Watched a ton and I feel I’ve learned so much. I currently liveaboard but I’m new to this life. Being a construction worker I’m financially challenged but very handy. With this information I’ve been able to enter a new way of life with confidence. Thank you so very much for all the knowledge I’ve gleaned from your content. So badly want a bank manager for my Pearson 40’s solar system and I’m starting from scratch. ❤

[@Clarks-Adventure]

I have a few black box 1.x units. Same electronics and software but $100 off

[@BigDreamsBoating]

@@Clarks-Adventure that’s good to know because function is my only concern. Soon as the budget allows thanks

[@brianwnc8168]

Your content and presentation is excellent. In the upper threshold of KZbin influencers that I've watched over many years. I hope you keep up the good work and are taking care of financially for it

[@johnmeyer7655]

I have motorhome with lead starting batteries and lithium house batteries. When the engine is running, the Alternator charges both systems. This means the lead batteries are there when the lithiums turn off at full charge, and the Alternator is protected from damage. When the ignition is turned off, the lead batteries are completely isolated, they will not charge with shore power or solar panels. But there is also no power draw, so they can sit idle for weeks at a time. When the ignition is turned off, the 2 battery banks are cemetery isolated.

[@Clarks-Adventure]

An issue you should consider is with the engine running your Li is being charged like lead (not good) and then floated at voltage over 13.48 (really not good). Are you considering a change?

[@tim1299]

@@Clarks-Adventure I thought you were giving me a green light for my motor home to have a lithium house battery. Now you are talking contrary with this response. I'm left confused once again.?? So I still won't buy a lithium battery for the house side of the motor home. And I thought lithium was to be charged at 14.4 to 14.6 volts to 100%. state of charge 13.6 volts. If I am charging and floating like a lead acid battery, how would the lithium battery ever get to full charge to shut down the BMT and destroy the alternator if no lead acid battery were present?

[@Clarks-Adventure]

That was in a very old video. I have learned a lot since then. That's why I developed the BankManager

[@tim1299]

@@Clarks-Adventure It was posted two months ago. OLD?? remove this video!

[@Clarks-Adventure]

What video are you referring to?

[@paulpozboater]

Love this, thank you Clark! I've learned so much from you. Hope you and Emily are well and I'm so glad you're back on the boat.

[@Clarks-Adventure]

Thanks Paul

[@apollo8352]

Great video.... having the starter battery permanently connected to the alternator and hooking the lithium in parallel through a battery isolator solves the high volt issue, then with a long 10mm2 battery cable about 10 m long going to the lithium house battery gives enough resistance to limit charging current so the alternator does not run to long at full amps...which is what I did on my RV I love the vee belt comment as it was also known as a wedge belt, noisy friction stuff. I worry that the thermal switch solution may not be so good due to the inductive reactance of the field causing back emf high volts causing the thermal switch a problems..

[@Clarks-Adventure]

Good point on the magnetic collapse and the switch. Could add a flyback diode to the switch to give a path. I should have thought of that.

[@patrickfitzoot]

More solid content, well organized. I'm definitely sold on the Bank Manager....but I don't have any lithium yet, so that order will be awhile coming. Cheers.

[@marc4322]

Great info as always Clark! Happy to see I am not the only one with vbelts that goes to dust! I will do the upgrade.😊

[@leo169]

Great idea with the thermally operated switch to control the alternator. Will store that one away for future use. 🙂

[@bhartley1024]

These thermal switches are so cheap, I don't understand why all motors and alternators aren't thermally protected. I once burned out a Makita planer just planing some hardwood. You spend all that money on a power tool and they can't put thermal protection on the motor?

[@johnnylightning1491]

Thanks Clark, now I have to figure out what kind of alternator I have. Keep the good stuff coming.

[@RichKernan]

Wow - so interesting to see how much knowledge you have on this topic. Thanks for the vid. I read all the comments and have simple question: We have a wake boat with your typical 90A alternator and a single lead acid battery that runs everything. I just purchased a Blue Sea Systems 7650 Add-A-Battery Kit ($125 on AMZN), which seems to be very highly regarded. I had planned to buy a 100AH LIFEPO4 (probably CHINS - $300) to use as a house battery to power the upgraded speakers and amp we just added so as not to run starter battery down when anchored and cranking music. My rationale being that the LIFEPO4 would be ok with getting run down, would last longer, etc. Having come across your video, I now know that the very low internal resistance on the CHINS will crush my alternator when I start the engine and the Blue Sea switches to allow the alternator to charge the house battery. Adding $380 for a Bank Manager is not worth it for my needs. Should I just forget about LIFEPO4 and get a marine battery, or maybe just charge the CHINS with a typical battery charger (one with a Lithium setting) when back in the slip and plugged in to shore power? My Battery Tender brand charger is 4.5 A and has a LIFEPO4 setting. I know it would take forever, but don't care. Thanks for any advice

[@Clarks-Adventure]

Lots of battery chargers nowadays have Li modes. That's marketing, they don't charge li as it should be charged. But I bet with the project you are planning you could be fine with the li dying in 3-5 years. There are a lot of right answers in life. I'd bet that your alternator wouldn't overheat. Id try it and see how it works. Give it access to nice cooling air and small stock alternators usually run cool enough in my experience. I suggest you watch my early videos on hybrid battery systems before I developed the BankManager. It explains the method of doing it safely. I don't think the add a battery is a good safe way to add Li. One should not allow li and lead batteries to connect at different charge states.

[@RichKernan]

@@Clarks-Adventure Thanks for the reply. Unless I have it wrong (totally possible) the Blue Sea never connects both batteries to the charging system at the same time. It's always one or the other. The only way to have both connect is to manually override to allow both batts to be used to start the engine if starter battery too weak. In that case, it would be switched back to normal after starting. I will check out earlier vids - thanks again for sharing knowledge. Super dumb question. If not Li, will any lead battery work as house battery in my application - or does not need to be a Marine one?

[@Clarks-Adventure]

Well exactly so you discharge your starter battery and ask the blue sea to do its thing. Now your Li is dump charging into your lead AND trying to start your engine at the same time. Ouch! What you want is a deep cycle battery with thick plates to handle multiple deep discharges. Forget marine. It means nothing but wing nuts on the terminals and marketers trying to turn a sticker into money.

[@adelarsen9776]

I think it's wonderful that you're helping people. Thanks Clark. :-)

[@brianhind6149]

Great Video ! The condition of the battery "spiking" is , I believe is known in engineering terms as "load dump " . I am amazed by how many people work in electrics or electronics, are unfamiliar\ with load dump , & its ability to destroy components. My first introduction to load dump was an automobile I had & the negative cable fell off the battery post (don't ask !) & every damned light that was "on" at the time instantly vaporized its filament.

[@brettschacher8644]

Referring to diode failures, back years ago, I was having issues with cheap reman. alts. I found the issue was cheap diode bridges installed in the reman's. I found a source for plasma bonded diode bridges which fully eliminated the future failure issues. The cheap bridges were soldered diodes which we all know has a low melting point. The diodes were simply falling out of the alt on the road as I drove along. Now not all alts are constructed so the diodes can simply fall out of the cases, such as late model Fords or many others. Not that long ago, I was working on restoring a Ford 7.3L powered PU which I had installed a reman alt. One day I was working on something else and sparks just lit up the inside of that reman alt. It was on account of a diode bouncing around inside the case which in the end pretty much destroyed that unit. This is the second vid I've watched today from Clark and they were both educational. I've been working on engines in boats and autos most of my life and have learned something even today after over 40 years of mechanic work. Of course very little experience with LiFePo4 batteries in cars has been the case. I'm really liking the hybrid battery concept now.

[@Clarks-Adventure]

Thanks Brett. Hope you choose to subscribe and continue to enjoy our stuff

[@brownnoise357]

very good insights for people, thank you Clark. 👍 Personally my next boatbis likely to need refurbishing and upgrades, along with replacements, Full wiring design check, Network Wiring, Lightning protection isolation and Bonding, New instruments (replacement originals that work, kept as spares for other boaters, and expensive but worth it Alternator, serpentine belts, external Regulator, standing rigging, running rigging, New Sails, and existing checked, valeted, and kept as a backup suit of Sails if good enough. That kind of thing. I'm still a bit wary of Lithium, after communicating with a Chinese Manufacturer. Like Lead, Lithium Hates being discharged below 50% Capacity, and you lose recharge cycles each time if you do it for longer life, they don't appear to like being charged over 85% apparently, so useful non damaging capacity appears to be between 85% and 50% , so a tual useable capacity would be 35% .? Now Lead Loves being charged to 100% right? So bon damaging capacity therefore looks to actually be 50% right, plus Lead batteries are easily and fully recyclable? Plus the extra weight, can help put displacement down low where it is useful. A badly treated AGM Battery can last as little as 18 months, but we'll looked after, 10 years. How long do badly treated Lifepo4 Batteries last ? What is their Maximum Life ? Information on those factors, are highly noticeable by their absence aren't they ? So I may go with deep Discharge Dual Purpose AGM, and Never Deep Discharge them (even with Lithium, deep Discharging Damages them. Any experience with Carbon Lead Clark ? They look interesting. As an aside, Offgrid on my Smallholding, I got 15 years outbof a bank of heavy Duty Cheap Agricultural Tractor Batteries, and only lost them thanks to Not forecasted extreme cold down to minus 45 degrees C cracking their cases. Never discharged below 50% and usually a couple of volts higher than that. I won't have "Normal" Lead acid Batteries on a boat though, must be sealed. Best Wishes. . Bob 👍

[@Clarks-Adventure]

Hi Bob, Carbon lead is very interesting and people I respect are having good luck with them. I haven't owned a set myself. I think you might want to broaden your research into LiFePO4. I think you will find evidence that a lot of your ideas about life and discharge are not exactly right. It's still early days for this technology but it seems to me that Lifepo4 can be fully charged as long as your charger can accurately know where 100% is. That can't be done with voltage alone so basically only my BankManager can do this safely. They seem OK with more than 50% discharge. In fact they should be stored for the long term at 50% charge. I set my lower limit to 20% so I get a working spread of 80% of rated.

[@brownnoise357]

@@Clarks-Adventure Good points Clark, Lifepo4 is indeed a Bit different, to Lithium, but that 85% charge maximises the service life of mobile phone batteries and Tablet batteries may point to it pointing that way for Lifepo4 as well. It was a pretty good Chinese Lifepo4 Batteries Manufacturer (pretty sure looking to sponsor me with a Housebank Set, to help them determine what the maximum useful service life could be if properly treated ) who was quite firm about the number of Recharge Cycles being harmed badly, if discharged below 50% Capacity, if done often. I suspect there could well be a way of treating Lifepo4 batteries, to get a useful service life of 20 plus years tbh. Though Tester Will Prose has said that, or at least strongly hinted, that Lifepo4 batteries will self destruct internally, a long before Cycle life can be reached. Now That I find worrying worrying enough, to seriously consider whether even a free Housebank set is really worth the bother of testing, and is certainly serious food for thought. Thanks for the thoughtful response Clark, Best Wishes. Bob (who does love testing stuff ) 👍⛵️✨️✨️✨️✨️✨️

[@brownnoise357]

@@Clarks-Adventure PS Me again Clark. I think I'm going to let others find out about Lifepo4 possible service Life, and as 10 years for AGM properly treated is now solidly established, I think a Carbon Lead Housebank with AGM e gine, bowthruster, and Windlass batteries as a setup for long term testing, will probably be the route I go , thinking about it. Thanks again. Bob. 👍 the edit was because the message decided to post itself before completion, so added the change of direction for me as well . 🤣

[@braithmiller]

Carbon lead Firefly make lithium look cheap.

[@brownnoise357]

@@braithmiller eta dropped letters from words. Luckily they aren't the only manufacturers, and Carbon Lead can be cheaper by a fair bit than Lifepo4 when on offer. AGM too, for a solid 10 year service life if treated properly, such as Never Deep Discharging any Deep Discharge Battery for starters, no matter the chemistry of its construction. You just need to develop an appropriate Battery Bank size, with a good routine for managing it. One Boat Owner, no names, no pack drill, an engineer ffs, absolutely Trashed his new AGM Batteries inside 18 months, and replaced them with very expensive Lifepo4 batteries. Did he change his management regime ? Nope, so bets may be taken on how long efore he trashes those Lifepo4 batteries. I would put money on them not lasting very long at all, and likely less than 5 years. Expensive lessons should be the best Education, Right ? Should have learned from his AGM bank that he wasn't doing things right imho, a nice guy, and he will probably figure it out in the end. 🤔

[@mottavator]

I just found your channel. I assume your device will apply to an RV system? I have a dual alternator system as this vehicle was originally an ambulance. I have removed the rear batteries and now have the original dual battery system for the diesel under the hood. I have upgraded one of the alternators and plan on using the other alternator exclusively for my "House" batteries which are lithium. As I understand from your video, If I install a lead acid battery as an intermediate to the lithium batteries and install the Bank Manager to regulate the alternator it should help my second alternator live to charge the lithium battery bank along with 1200 watts of solar. Thank you for this video which has come up on my youTube home page!

[@Clarks-Adventure]

Yes it will work fine in an RV. In fact we just did a 3 month RV trip through the rocky mountains. kzbin.info/www/bejne/lX6TgJx3npqle68

[@Nerd3927]

Excellent! I use a DC DC converter from 12v to 24v since my house battery is 24v, but I never thought of a thermal switch as a protection. Very simple and cheap :-)

[@4runner4ever83]

You made this more complicated. I have a lead battery as my starter battery and is using a dc-dc charger for my agm battery. I use this in a car setup. Please note i can use a lithium battery but too expensive for my needs. My agm is only used to power my fridge during a road trip and camping. I created a video on my channel about it and works like a charm.

[@Clarks-Adventure]

Your needs are simple Others need different levels of performance. I, and many other commenters, believe this was just as complex as it needed to be.

[@Clarks-Adventure]

Not really. Ask yourself this. What voltage do you set your dc-dc charger to? The more research you do the more you will realize there is no correct answer. You can't safely charge li to a voltage. Lithium requires a specific charging method that simply can't be met by those devices.

[@Clarks-Adventure]

Yes I'm talking about lithium specific chargers of all types. They all charge to a voltage. What voltage?? It's different for every current being delivered to the li cells.

[@badactor3440]

@Emily & Clark's Adventure The Renogy DC to DC charger can be set to 4 different voltages by setting the 5 "dip switches" to a predetermined configuration. 14V, 14.2V, 14.4V and/or 14.6V for Lifepo4. It also can be set to charge LA. 12.6V, 12.8V and/or 13.0V. I'm using the 14.4V (lifepo4) setting, which is widely recommended by many manufacturers of lithium batteries, including mine.

[@Clarks-Adventure]

I know. I own one. I'm saying there is no right answer for every charging rate. If you charge at 20 amps one day there is a setting that's right. Then the next day you charge while there is a load, say your refrigerator is running at 7 amps. Now you are charging at 13 amps and you need to stop the charge cycle at a lower voltage. There is no one voltage that doesn't cause low current overcharge. This causes irreparable damage to the cells. Also repeatedly not charging to full causes memory.

[@detlefdaniel6106]

I'm usually not commenting on you tube clips, but i think i can add some useful info. For those who have newer boats with 2014+ Yanmar YM.. engines, they are all equipped with 125A 12V Valeo alternators, which have internal regulators - simple (dumb) voltage regulators. The video suggests to add thermal switch in the field current path to prevent overheating the alternator when LiFePO4 is used. Indeed, there is a Yanmar Tech bulletin out (YMTQTB17-007), which recommends to limit the charging current to 100A. This will limit the alt temp to 200 deg C, which seems high, but apparently is OK for Yanmar. Now, a thermal switch can accomplish this, but it does not address the voltage spike problem. Here is why. I'm assuming a typical scenario with lead acid starter and LiFePO4 house battery bank, both separated by a battery isolator. The LiFePO4 batteries typically use a battery monitoring circuit (BMC), which will shut off when a single cell (there are 4) reaches its max voltage. This shutoff happens instantly with severely unbalanced cells. The lead acid battery starter battery is normally fully recharged after a few minutes and therefore won't act much as a buffer raising the charge voltage above the 14.4V limit. The only way to remedy this is a controlled ramp down of the charging current so that the regulator can follow. So far i haven't found any specs for ramp down of BMCs, maybe someone can enlighten me.

[@martinsonneveld440]

Thanks for discussing this! But why so hard on DC-DC Converters? Yes it's another green or blue box but I installed one it works flawlesly and doesn't need a lot of attention, you can easily adjust on charging profile, set voltage, amps, duration so it can nicely work together with what you already have. No need to fiddle with alternators, easy install and not more expensive than alternator and regulator upgrades. Very easy to live with last 2 seasons, and solves both issues you rightly brought up here! While Lithium takes a charge so easy you hardly have to max out on alternator power, In parctice I rarely draw more amps than 1/4 of the rated alternator output (115A), most of the times its set to 25A.

[@Clarks-Adventure]

I have used dc-dc chargers. Sometimes they are a good solution but usually they aren't. My issues: They are mono-directional. Can't move solar power to the start battery. They waste power (minor issue with power to heat but major issue since they can't pass much power. As you said seldom 1/4 of the power available. They don't charge li correctly. They charge to voltage not to full. See my recent video on the BankManager for a definition of low current overcharge. They are basically unnecessary. Hybrid batteries are better if managed property. But we are all captains of our own ships and should do as we wish.

[@martinsonneveld440]

@@Clarks-Adventure true, all choices are personal, only wanted to add my positive experience here.. to react to your points: I connected the solar power to a Blue Sea 1-2switch (after the solar charger) to choose banks manually. When not aboard it is switched to the lead acid starterbattery. The DC-DC Charger can be set to stop charging the Lithiumbattery ones Tail-current thresholds are reached, in combination with the apllied voltage (eg 14,0 Volt at the Li-battery), just like the solar charger or the shorepower charger (all monofunctional on purpose). I am least worried sofar on the efficiency of the setup, more to (losing) simplicity and how to save or enhance some sort of redundancy. I am very interested in your creative solutions and will sure look into the benefits. Many thanks for your time and efforts!

[@Clarks-Adventure]

Which dc-dc are you using? I've only tried the renergy. Be careful with the battery combiner switch. If your lead is quite discharged li can try to send LOTS of current into it. We have seen some smoking wires during tests.

[@martinsonneveld440]

@@Clarks-Adventure I installed the Mastervolt MacPlus 12/12-50 2 years ago, as part of a total overhaul of the electrical system. Can also act as a stabilized (max 50A) DC-source, so if Lithium is down engine can be used as generator (for basics: nav, autopilot, lights etc, not microwave). This Blue Sea switch has deliberately no combiner function, it is in to be able to maintain control over the solar charging.

[@Clarks-Adventure]

Thanks

[@AN-kg4ei]

I just picked up 2 100A Eco worthy lithium batts and likely won't be long before wanting a BM regulator from you Clark! In the meantime I might do a little DC to DC charging experimentation.

[@Clarks-Adventure]

Careful with overcharging if you charge slowly I'd set the charge limit to something like 13.8v and have it float to 13.3 right away after it hits 13.8v

[@jemdost6724]

Such an excellent video. I'm convinced you can confirm if my expensive way of keeping my alternator in check will work for my upcoming project. Mind you I'm installing these on a yamaha jetboat (because I have a very demanding audio system) So I bought an Epoch lithium battery 12v460Ah claims the following statement on the website: " CANBUS Communication allows BMS to communicate directly with Victron OS" I also bought a Balmar XT 250 alternator. I will be buying the all new Arco Zeus external regulator (it is a canbus enabled regulator similar to the wakespeed WS500) I will also buy a victron cerbo GX. I'm hoping the Epoch batteries internal BMS will connect to the Cerbo GX to be able to enable DVCC and then from the Cerbo GX to the Zeus regulator which then will control the Balmar alternator to shut off when my lithium gets full and stops accepting charge or out of balance etc any time it shuts downs. All concept and I already bought most of the expensive parts but really would appreciate if you would look into these specific products. I have a good feeling you will be familiar with the individual items I have listed and will have a stronger opinion on if they will be able to communicate in the way I'm hoping. Looking forward to your reply and thanks for the videos, cheers!

[@Clarks-Adventure]

No I haven't put that exact system together as I solve this a different (better) way with my BankManager. It can't fail and actually charges your Li correctly unlike these devices. It's also much cheaper. I suggest you ask this question to the guys buying from.

[@jemdost6724]

I see so what happens if the Lithium BMS shuts down unexpectedly, does the starter Lead Acid Battery or AGM battery absorb the extra current so it doesn't damage the alternator plus all the other electronics?@@Clarks-Adventure

[@Clarks-Adventure]

Yes exactly. And since my hybrid battery manager always keeps the lead on line, it's always there to absorb the energy. Nothing can fail.

[@jemdost6724]

@@Clarks-Adventure amazing I’ll watch your bank manger video first chance I get to learn more

[@Clarks-Adventure]

This might also prove helpful. www.emilyandclarksadventure.com/bbms

[@bmunday]

so glad I heard about you from another cruiser. this is HQ content! Thanks clarke!

[@InspiredByBrad]

Our RV (Pleasure-Way) uses the factory Mercedes Sprinter 200 amp alternator connected directly to 2 100AH Lithium batteries via a timed switched solenoid. The amps range between 90 and 130. It seems to function well.

[@Clarks-Adventure]

Glad for you. Have you ever had the BMS disconnect?

[@jroschella]

Glad to see you back on the boat.

[@reginaldpotts2037]

Greetings from Portugal, Europe. Not sure why your video appeared in my YT feed but nevertheless, information greatly appreciated. Thank you.

[@Clarks-Adventure]

I hope you like our other offerings

[@ianwillcock6314]

Great video as always Clark, now that I know the bbms will protect my alternator from my lithium I can stop worrying about it.

[@Clarks-Adventure]

Thanks Ian

[@hinoonenterprises]

Do I need a new voltage regulator?

[@cliffweinan3907]

Good point about loss of battery load killing alternator, especially on diesel with no engine electical load. How about simply keeping the alternator / regulator always lightly loaded with a couple of engine comparment light bulbs?

Very informative. Interesting approach. Personnaly I would probably use a slightly different approach. For the charging: Having a lead starter battery and wiring in a charge controller that draws from that battery and the alternator, combined with a low voltage shutoff setting, so it can not drain your starter batttery. Easiest is probably a solar charge controller that can handle the voltage of the alternator. regarding the heat issue it depents on how much power you want to draw, either have an electric fan controlled by the alternator temperature that adds cooling when the tempt gets too high, or, preferrably, use a liquid cooled alternator, that is cooled by the engine cooling system. This is especially useful for high power alternators that put out power in the Kilowatt range and can charge large battery banks. not the cheapest solution, but the cleanest from a technical point of view and with minimal additional effort since you need to cool the engine anyways and engine temperatures are in a similar ballpark or lower than the allowable temperature for your alternator. Of course this approach is useless with aircooled angines, but those are rather rare in marine applications. Benefit of using something like a victron BlueSolar MPTT 100/50 with a 24V alter nator and a 12 Battery bank - or a 48V alternator and a 24V Battery bank is that it will not just limit the current to what it is specced for (you can use more than one in paralell if needed, but it can deal with the BMS and its shenanigans and protect the alternator. if used with a seelctor switch that allows to swithc to solar input it could also act as a spare charger in case the main solar charger is damaged. in that case you just move the voltage source fron your alternator to your panels - or some of oyur panels to keep the voltae with in the spec.

[@bendegroot8234]

Victron tells dont use a mppt as dcdc between two banks. They have another product for this the Orion dcdc.

@@bendegroot8234 if they have a dedicated device for that, even better.

[@jimanderson4444]

Good work Robert, I like the solar connections . An offgrid system and my old Toyota ice running some big water cooled alts for backup has been my plan. Jim.

[@kb9knd]

I enjoyed this video. The idea I had when you were talking about using the lead battery to protect the alternator when the lithium battery opens it’s circuit and stops charging was, would one of those super sized capacitors used in audio amp installation work in place of the lead battery? The capacitors I’m talking about are over 1 farad and some even have digital voltage displays built in. Capacitors life generally lasts longer than lead batteries. Just a thought. Thanks for the interesting video. This is the first time I’ve seen your channel.

[@Clarks-Adventure]

Technically it would solve the problem nicely. But,, it creates so many problems of its own. It's hard to control current with one of these. Its charge acceptance ability is scary.

[@svStargate]

I’ve always asked myself if a blackout was possible when BMS disconnects.. wasn’t sure if it only disconnected from incoming power or disconnected the whole thing.. now is clear.. doesn’t sound good to electronics and a little annoying..

[@tiny3669]

I run a dual alternator set up and have my battery bank on a 375 amp alternator with a external adjustable voltage regulator. Works great.

[@Clarks-Adventure]

I don't understand. Alternator hooked to battery works. Of course it does.

[@jimjones7821]

@@Clarks-Adventure Clark, I think he is just saying that he has a system setup as he notes and it is working out really well - thats all. I dont think he was posing any sort of question at you.

[@Clarks-Adventure]

Thanks, after reading and answering hundreds of questions I guess everything starts looking like a question.

[@TheRedneckAtheist]

You could just add a capacitor bank at max regulated voltage+10%. Hook the capacitor bank directly to the starter and have a cutoff between the battery and the bank for safety if/when you need to work on the electrical system. But I fully admit I have almost zero knowledge of boat systems other than the critical systems tend to be more on the side of "lose this while in the blue and you could die" sort of critical.

[@Clarks-Adventure]

I don't exactly know how to size one but I'd really like to know. If you experiment please share. Adding a 20v zener diode might help a lot as well both to bleed off power and keep the caps from popping. I'm glad you understand the potential danger from big caps.

[@davidconner-shover51]

@@Clarks-Adventure I built a small system with a 300ah battery and a 500farad supercap, it did wonders, from starting up heavy motors (engines, compressors) well beyond the BMS low voltage cutoff voltage and current

[@Clarks-Adventure]

500 farad pack or a pack made up of 500 farad caps? Last I looked these were low voltage and had to be in serial

[@davidconner-shover51]

@@Clarks-Adventure yeah, mine looks like a six pack parked on the back of my inverter 2.7v 3000 Farad actually. This six pack can, will and does deliver however. it certainly allows my measly 300Ah (BMS cutoff at 200Amps) LiFePO4 and 2500W true sine inverter to start a 3HP compressor without issue, the lights don't even flicker. as well as a 305 engine. these suckers can deliver the instantaneous current in ways even a lead acid can't it'll cost a few hundred, but its worth it. no more blown out charge controllers, alternators or inverters.

[@vroor32]

​@@davidconner-shover51 😢 damn, my guy .... You are speaking Greek Latin gibberish right now.... I have no clue where to start ....

[@hyperchannel4048]

You can buy alternators with watercooling. But power is amps times voltage and torque times rpm so lower rpm needs more torque and a stronger field. That wears out your alternator. You can chose the pulleys in a diameter that gives your alternator more rpm even during idleing. But keep an eye on the bearings. At sea there is.nothing more reliable than a standard alternator and a standard lead acid battery to keep you able to start the engine. Keep that in good and original condition. Make anything else with a second alternator and its own belt. The guarantie and the insurances will tell you that anyway. You can protect your system against overvoltage with a varistor or surpressor diodes. A save and dry stored spare alternator and a magnet is worth its weight in gold. Have you seen the new capacitore based jumpstarter? Supercapacitors are able to start your engine. With an step up converter and a solar panel or a weak battery you can always start your engine. But do not shortcut or overvoltage them. A lot of.information here thanks for sharing!

[@bjrnetveter253]

All hail the alterntor god 🙂 Thanks for the tips. Useful.

[@Kosmonooit]

The charging voltage for Lead Acid and Lithium is different, that's why a DC to DC charger for the Lithium is a good idea. Also higher than rated charging voltage for Lithium can shut down the BMS

[@Clarks-Adventure]

For the best answer to all this check out www.emilyandclarksadventure.com/bbms

[@sifilmaker]

This is how RVs are setup.. lithium batteries are connected to the started battery through a DC-DC charger. BMS are pretty stable nowadays, even the old crappy Chinese ones have become better and beefier than ever. The price of lithium batteries have dropped dramatically if you are running Lithium you should have an alternator that has a higher output. Best days of a boart owners life, the day you bought it and the day you sell it. I loved my boat but man was I glad I got rid of it. lolol Nice video..

[@Clarks-Adventure]

That's a way you can set up an RV. My camper uses the BankManager approach as you might expect. Once you take the little life jackets off the electrons, boat and RV electrical systems are very similar.

[@brianbuchanan5170]

The communicating BMS, as should be the standard, interrupts the regulator. It could be as simple as a relay breaking the wire that energizes the alternator. A smart BSM will actually test and validate charge control functionality on a periodic basis. Actually disconnecting the battery should be the absolute last resort. Now it’s not only the alternator that can cause issues but solar chargers, generators, or shore power chargers. All of those potentially need to be slowed/stopped. A second method to slow charging equipment is to have a step-up DC signal for the voltage indicator at the BMS which can suggest to older equipment that the battery voltage is higher (such as 15 volts) and allow the equipment to slow charge that way. The problem is the inexpensive lithium batteries are designed to be small, cheap, and modular without considering how to protect the whole system. It’s much easier to package a whole “replacement” battery instead of individual cells and a single common BMS - one using relays and a shunt or two instead of relatively high resistance mosfets.

[@Clarks-Adventure]

Your statement seems like an argument to do it my way. Easier, cheaper and pretty bullet proof.

[@retiredguyadventures6211]

Great video! I am new to lithium batteries. I had an AGM battery in my cargo trailer hooked up to the alternator from my tow vehicle so it would charge along with the tow vehicle's battery while driving. I recently bought a LiFePO4 100 AH battery for the cargo trailer because I want to put a solar charger on it, and it has a 100 amp BMS rating. Basically I had the cargo trailer AGM battery in parallel with the tow vehicle's lead acid battery for charging off the tow vehicle's alternator when driving. I have a couple of questions. #1 - Can I even put a LiFePO4 battery in parallel with a lead acid battery and charge off an alternator? #2 - If I can put the two batteries in parallel will the tow vehicle battery act as a shunt to prevent the voltage spike when the LiFePo4 BMS shuts off?

[@Clarks-Adventure]

I have several videos on this topic . You can do it manually but it's best to use my BankManager if you want the best life from your batteries. I suggest you watch through my videos on the topic. Check out playlists.

[@FlextheJuvat]

What about this scenario: In a vehicle, using a LiFePo battery as an aux battery, installed with a battery isolator? The alternator would charge the lithium aux batt, and the lead acid starting battery, and would always have "something to do" w/ regard to charging and operating the vehicles systems as it did prior to putting in the auxiliary lithium batt. Am I missing something? I'd like to add an aux batt to my truck, and lithium sure is appealing! Thank you! (edit: for context, the aux batt is only for running a portable refrigerator that runs at 60 or 45 watts, depending on Eco mode selection ... so I'm not trying to power heavy equipment)

[@Clarks-Adventure]

From the alternators point of view no big issues assuming it's continuous duty. From the li batteries view. Yuck. It's going to be cooked being charged like a starter battery in a car. 1 to two years life, tops. You should use this instead of the isolator. www.emilyandclarksadventure.com/bbms It will control the charge to the li

[@jackpatteeuw9244]

And even simpler solution. Leave your existing or upgraded alternator connected to your existing flooded lead acid engine starting battery. Buy a dedicated DC-DC lithium battery charger. Wire it between the 2 batteries. It will "properly" charge your lithium battery through multiple steps. If will also prevent any damage to your FLA and alternator. Yes, these DC-DC chargers LIMIT the current to the lithium battery so it will take longer to charge.

[@Clarks-Adventure]

They also cause low current overcharge damage to the li

[@ii1825]

DC/DC chargers are bad for LiFePo batteries? First I've heard of this. Care to expand on this? These type of chargers are used all over the place in overlanding vehicles and I have not heard many if any complaints. Shouldn't matter if it's a land or sea vessel.

[@Clarks-Adventure]

Read Conrad's article linked to the bottom of this www.emilyandclarksadventure.com/bbms As a start to research. All chargers currently available (except mine) cause low current overcharge which seems to kill LiFePO4 in as little as 3 years. Li should live much longer than that.

[@ajf9034]

@@ii1825there is nothing wrong with dcdc for lithium housebanks, it’s the simplest and safest way to charge a lithium battery from an alternator and their regulated charge current will lead to the longest life possible as regular rapid charging decreases battery life even with lithium, any reputable lithium battery manufacturer may allow a 100 amp max charge for example but the recommended charge current may only be 30 amps for maximum longevity. Old mate here needs to try some redarc or Enerdrive products which have adjustable tail current so low current overcharge is not a problem. Keep it simple, lead acid start battery or batteries and a lithium house bank charged by a dcdc charger with an inbuilt mppt solar regulator and a shore power charger.

[@MikeSantis]

Fantastic. Thank you Clark. You explain things in a way for us that don't know much about this stuff so we can understand.

[@Clarks-Adventure]

Thanks Mike

[@Eduardo_Espinoza]

thinking of parallel connection (pbo2 & lifepo4), alternator connected only to pbo2, hopefully balance-charging changes the lifepo4 battery too :). thanks for bringing this to our attention :).

[@Clarks-Adventure]

You should consider the BankManager for that. www.emilyandclarksadventure.com/bbms

[@lloydevans2900]

How about this for an idea: Get a 12 volt powered fan (like an old car radiator fan) and position it so that it's blowing extra airflow directly at the alternator. Then wire up the fan through the "normally off" contacts of a DPDT relay, with the relay coil powered from the alternator output through one of those thermally activated switches - with the switch mounted to the hottest part of the alternator of course. That way, if the alternator does overheat and turns the switch off, this will turn the relay coil off and therefore turn the fan on, blowing extra cooling air over the alternator. Or, if it's possible to get a type of thermal switch which which turns itself on when the rated temperature is reached (rather than off, as the type you described does), you could dispense with the relay and just wire up the fan directly through the switch. I had a similar setup several years ago on a rotary vane vacuum pump in a chemistry lab - the pump was old but still worked most of the time, probably had slightly swollen vanes so the motor had to work harder than it was supposed to, so it would overheat, especially in the summer. Like an alternator, the motor had its own integral cooling fan, but that wasn't enough, so I rigged up a couple of 120 mm brushless fans to blow extra cooling air over the motor, which stopped it overheating. The pump had its own thermal cut-out of course, which would save the motor from catastrophic heat damage, but that was a last resort since keeping the vacuum running was the main priority.

[@Clarks-Adventure]

Yes. I wish I had mentioned the obvious solution. First improve cooling! Those switches are readily available as NO and NC

[@scottworelds2933]

Wouldn't a lead acid or AGM battery in parallel solve the issue ?

[@Clarks-Adventure]

That's what the video is all about. That and how to make the two chemistries play nice. You might want to rewatch the video

[@jamesmason7124]

Hello my name is James Mason and I live full-time in my 1967 GM TDH-4519 new look city transit bus, it has a Detroit Diesel 6v71n with the Delco Remy Dn-50 gear driven oil cooled brushless 12 volt 225 amp generator but I plan on replacing it with a 450 amp version, i would like to get a Wakespeed ws500 controller but i don't know if it will work with a dc generator. I plan on having one 1000 ah lithium iron fosphate battery bank using 520 Headway 38120 hp 8ah cells for both house loads and starting the engine. What would you recommend?

[@Clarks-Adventure]

I don't know much about modern generators. The last car I had with one was a 1955. I'm really surprised you aren't using an alternator. Maybe it's a bus thing. That's a lot of headway cells. Like 500. Those things aren't cheap. Why not go with big prismatic cells? And a BankManager of course.

[@jamesmason7124]

@@Clarks-Adventure the reason I am going with the headway 38120 HP cells is because they put out enough current to start my bus and they are cheap, about 200 USD for 48 cells. I forgot to mention that I will be using a Rec 500 amp bms that also controls contactors for input and output and that both the Wakespeed ws500 and the Rec bms will be connected and controlled by a Victron cerbo GX

[@Clarks-Adventure]

How much for the 12v rec?

[@jamesmason7124]

@@Clarks-Adventure about 500 usd

[@grakkerful]

Well, I picked up some thermal switches. Looking forward to the next video so I can learn what to do with it.

[@Clarks-Adventure]

Someone suggested a potential problem with this. He might be right. Adding a flyback diode might help protect the switch for longer life. I'll talk about it in the description of the next video. Too late to film anything.

[@grakkerful]

@@Clarks-Adventure I'm looking forward to it. I recently upgraded to 200Ah of Lithium (27' sailboat) and I've been a little worried about how the rest of the system.

[@Clarks-Adventure]

I just updated the description of this video to talk about it. I basically said check wikki. What I really should have talked about in the video was venting the engine room. I think I'll add that to the description now.

[@coachgeo]

THANKS for putting this video together.

[@Clarks-Adventure]

You're very welcome

[@Clarks-Adventure]

Hope you enjoy our other videos as well

[@coachgeo]

@@Clarks-Adventure been thru them numerous time and purchased (but not installed yet) a BBM+

[@wildandwackywade]

Does these techniques also work on my RV since a lot of us have to use lithium batteries with our solar panels?

[@Clarks-Adventure]

Yep same thing You just have to take the little life jackets off the electrons.

[@DigBipper188]

One other thing that could really help with thermal regulation would be to opt for a compatible liquid cooled alternator. This should remove some of the RPM dependence to your charging system as there will always be a good constant flow of coolant through the alternator.

[@Clarks-Adventure]

I haven't seen a lot of these.

[@sailingrumrunner]

I have a Yanmar 56hp diesel which I think has an 80amp alternator. My starter battery is two 6V deep cycles in series for 12V. I have a victron 18amp DC/DC converter fed from alternator to two 12V 206ahr SOK LiFePO4 batteries. I like the idea of the thermal switch and having spare diodes on board. Any advice or critique here? BTW, really love the way you explain things. I am a retired chemist and typically chemists and engineers don't see eye to eye. My eyes , and ears, are wide open. Thanks Captain Qwiksword SV Gratitude Cocoa Fl.

[@Clarks-Adventure]

Thanks. I'll assume your request for discussion is for others as I'm on record. Also glad you read about the flyback diode.

[@szki272]

How about replacing the alternator with a permanent magnetic alternator like they use in windmills then a charge controller?

[@Clarks-Adventure]

That's called a generator. Cars had them before diodes were invented they kinda suck and you can't regulate them.

[@71970eli]

Brand X alternators can make you an alt that will have zero care in the world while charging your lithium battery. They make an alternator for just about any engine with amperages rating from 180A- to 540 amps.

[@gigioecu]

So I want to deck out my electric system in my Catalina 22. The goal is to do the Texas 200 comfortably. But is ac, inverter and lithium to much for such a small boat such as mine?

[@Clarks-Adventure]

Sailing is a hobby. Do what makes you happy!

[@larrydugan1441]

Excellent video Clark. Really informative. Thanks

[@Clarks-Adventure]

Nice of you to say Larry

[@lonniedomnitz1720]

This content is great! Thanks! What is the minimum size Watt hour lead acid “shunt” battery required when using lithium batteries? Just installed a Mechman 400 amp alternator that can handle 250F+. This will feed a 4000watt inverter installed in F250 truck crew cab to charge my electric motorcycle. Ordered a 16 Amp NC. Temperature switch. Will also use a fly back diode. Might get another one to monitor the starter batteries for the inverter temp sense input. Exciting stuff 😅

[@Clarks-Adventure]

Lead size with a BankManager is all about what's required to keep your charging system "sane" when the li is disconnected. Some systems require more than others Starter type batteries work best but they should seldom be power cycles of course

[@lonniedomnitz1720]

@@Clarks-Adventurejust looking for the formula to calculate the lead acid battery size needed to shunt the back EMF generated by alternator when the BMS disconnects the 140 amp hour Lithium battery. For example . Will a 1 amp hour lead acid battery work?

[@Clarks-Adventure]

If you let the BMS shut down your Li damage is happening to that li. Use a BankManager. BMSs aren't battery charging devices. They are for emergency situations Usually a car starter battery works

[@campnut6076]

How do the Balmar regulators deal with the BMS shutting down the batteries?

[@Clarks-Adventure]

I wouldn't expect them to do that well. It all happens so fast. Opinions? Experiences?

[@dyslectische]

Cheap and easy way ? Pwm controller with lithium support . Done . You connect it to your lead Battery. What u use for to start the engine . And set it on your Lithium. Switch to set it on or off . If you go full lithium than u use dc to dc converter. If you have low power alternator like a small one outside engine you can use a pwm .

[@Clarks-Adventure]

It's not that simple.

[@willwalters7765]

Is it safe to have alternator connected to lead starting battery through stock wiring, then wired through a simple isolator and ignition-operated relay to the lithium house battery?

[@Clarks-Adventure]

Generally yes in the days before Li. Since with that approach you might be connecting a starter battery to a well discharged Li (that has low internal resistance) you should verify your wiring is up to the task and proper fusing is installed.

[@funlovingJohn]

My toyota hybrid does not have an alternator, Will a lithium battery instead of the 12V lead acid battery hirt the 12V charging system in the phase converter?

[@Clarks-Adventure]

Your charger circuit is going to treat the LiFePO4 like lead. It will work but won't last a long time.

[@kbwaldron]

confused. You mention the BMS shutting down the battery charge will blow the diodes. But then you propose a thermal switch that will do the same thing. Why does the switch not cause the same diode issue?

[@Clarks-Adventure]

The BMS opens the current carrying circuit causing a rise in voltage. The thermal switch opens the field circuit causing a drop in both voltage and current in the current carrying circuit. They live in different circuits. If you are still confused watch the two videos again after reading the above. I bet it will make perfect sense

[@kbwaldron]

@@Clarks-Adventure thanks. I get it.

[@tracker001]

Sailing Yaba , needs to see this !

[@johnreuteman2724]

Do outboard alternators die from the same BMS disconnect? Are the fixes the same as well?

[@Clarks-Adventure]

I don't have much experience with outboard alternators. I'd hope they would be battery removal tolerant as they are basically portable. But if they are prone to the same failure a hybrid system would protect them.

[@johnreuteman2724]

I have a small outboard and want to charge my new LIPO4 battery from the outboard. The 5 amp alternator is built in to the outboard. Do I have the same risk of blowing Diodes if the BMS turns off the LIPO4 battery? I don't have a starting battery since the outboard is pull start. Do I still need to add an AGM to protect the LIPO4? Can the AGM be a motorcycle battery, (~20 AH)?

[@Clarks-Adventure]

You won't hurt the outboard alternator because it's designed to operate safely with no battery attached at all. But your alternator will charge your Li like lead. If you never charge the li fully no problem but if it fully charged the outboard will be the absolute poster child for "low current overcharge" which kills LiFePO4

[@zooksa]

Is there a reason that highly quality DCDC chargers used in automotive and caravan systems don’t work? I have had a dual battery system in my 4X4’s for years and never had issues with Redarc or Victron DCDC chargers. I know people who have used other systems with success as well. Here in Australia we have access to some really top shelf products which protect both our lithium batteries and charging systems.

[@Clarks-Adventure]

It's not that they don't function.. They charge li to a voltage which shortens the li battery's life. They can only operate in one direction. And they are inefficient. Anything with fans or heat sinks wastes power by definition

[@johnharden6343]

So you briefly mentioned connecting the new lithium with the existing lead which is still connected to the alternator, but can that simply be done? And just let the BMS take care of the new lithium but isolated with a key operated solenoid

[@Clarks-Adventure]

Well it can be done simply with a BankManager www.emilyandclarksadventure.com/bbms

[@SolarBuck]

any plans to do 48V. i have a NiFe battery comprised of 36 600ah cells i had to put this in a shed do to hydrogen off gassing. i interested in expanding with Lithium LiFePo4 but have been looking for a way to get them to play nice. this looks promising but i could only find 36V version

[@Clarks-Adventure]

The BankManager does 12, 24, 36, and 48v

[@lureup9973]

Could an in-line capacitor be wired in a way to absorb the extra energy, enough to prohibit the issue?

[@Clarks-Adventure]

I've been getting this question a lot. I don't like capacitors in the power system due to current control issues. I feel they cause more problems than they are worth. But yes a big enough cap bank could absorb the energy until the regular could catch up.

[@lureup9973]

@@Clarks-Adventure thank you for the quick response!.. great content and great delivery!

[@kristiqntachev7139]

Hey there! Do you think that having a Smart BMS where you could control the current flowing out of the battery can save a lot of hustle ? Since i have limited my Smart BMS to only be able to charge with 35 Amps so there is no draw which exceeds these amperages. I am currently having a hybrid 2 x lead acid 100ah + lifepo4 100Ah and i am planning to change the cells to 280 Ah Eve which will consume a lot of current if i let it too. Great videos i am a big fan from many years :) Cheers from Bulgaria

[@Clarks-Adventure]

No removing all battery loads from a spinning alternator is never a good thing. And I'm not sure what you mean by a smart BMS able to limit current. If it's doing it by signaling the charge controller, fine. But itlf it's doing it itself by adding resistance I can say I like that idea much. But there are a lot of "right" answers in this world. It's just a matter of finding the one that works for you.

[@hiteck007]

Mate I've killed 2 alternators with an AGM 2nd battery and a DC to DC charger. We suspect somehow the alternator Overheated even though it's only under a 40% load. Alternators are rubbish these days, since I got rid of the DC to DC charger, no more blown alternators.

[@stephenburnage7687]

Would a further option be to add an invertor as the load on the alternator and to feed that into the existing smart charger? Kinda like a DC to DC convertor but employing the existing smart charger. (Note: i charge my batteries from a stand alone gen set, by feeding the smart charger).

[@Clarks-Adventure]

That seems really unnecessary and a huge waste of energy. The hybrid battery approach with a BankManager gives many many advantages including proper charging of your Li bank for much longer life.

[@stephenburnage7687]

@EmilyAndClark Can you explain why you consider it a waste of energy? Inverters have an efficiency of 85% plus and so do smart chargers. Moreover, if I am only charging this way when the engine is running, the increase in diesel fuel consumption is marginal. Isn't the issue more a question of whether the smart charger will accept an imperfect sine wave (although mine accepts the output of a Gen set), cost and space (would need a 40 to 50 A Inverter). Not keen on the alternator being dedicated to a (lead acid) start battery as would have to reconfigure or remove the combiner arrangement.

[@Clarks-Adventure]

You can do it anyway you like. I suggest this approach. www.emilyandclarksadventure.com/bbms Sure it's like 20 percent heat waste TWICE. If that doesn't bother you go for it. I'm not going to engineer your system in a direction I don't believe in. My approach has a lot of advantages but if you only concentrate that it's the only way to charge li correctly for a long life that should be enough. It's just extra points that it is a simpler more robust approach.

[@termiterasin]

My new favorite gear is the Renogy 50A DC to DC charger with MPPT. For $300 there is nothing that is a better value. 50A of solar or 50A of alternator charging for any battery type and very safe for lithium.

[@Clarks-Adventure]

It causes low current overcharge.

[@nordic5490]

Ok... when I use my big air compessor in my 4wd, this thing draws 90A from the battery with the engine running, pulsing on and off, and the alternator doesn't blow up (and pumps the tyres up fast). I used to be a surveyor out in the remote part of nothern Oz (NT), and once a month or so, I had to use the winch to get out of a bog, no Idea of the winch current, but, I think 200A would be in the ball park. On off on off... and the alternator didnt blow up on 2 80 Series landcruisers, and on 2 GU patrols. I never heard of an alternator blowing up this way ever. No one has mentioned it. I Was working in the NT for several years. And some are very hard on their winches. So, if very high loads, eg 200A can be pulsed on and off with the alternator running, plus all the back emf that ensures, and the alternators survice (they all do on 4x4s running winches and big compressors in the bush) , then there is no way a nice gentle easy peasy dcdc converter, with its soft start, can damage the alternator by causing overvoltage ramping the battery itself has verylow internal impedence and is a massive 13v clamp. Did you put a scope across the 12v to verify this theory ?

[@Clarks-Adventure]

As I say in the video a good continuous duty alternator should have no problem with overheating if installed well. The problem is on boats the owner falls for buying a hugely rated alternator. Something that can put out 170amps but is built in a small alternator case has trouble cooling itself over hours and hours of full performance. Sure a dc-dc will solve this by imposing its 40 amp current control but it has loads of other problems. The bigger threat to alternators is (as I describe in the video) when the BMS removes the lithium batteries suddenly from the charge system. With your experience you must know that suddenly removing the batteries burns out the alternator diodes??

[@Mountainmandean207]

i love your videos as a new sailor the are so valuable thanks

[@overlandready]

All alternators have a regulator, so that limits the voltage the vehicle sees, that will remain at no more than 15VDC! What does actually happen is the battery draws very high amperage, as the volts DROP off, as the BMS regulates the Watt input to the battery. The alternator is not destroyed by Voltage, it is destroyed by HEAT! ps an alternator produces about 250vAC then regulates it. You can use an alternator to run a mains generator. The simple way to stop the Lithium from cooking your alternator is fit extra and efficient cooling, secondly fit a volt sensing device that has overvoltage as well as undervoltage cut offs, have a smaller sacraficial L/A battery so the alternator is not subjected to heat spikes from being disconnected, The other MUST is a ingition relay that instantly removes the lithium from the systen when the engine is shut off, this avoids the amp spikes when shutting off. A DC/DC inverter cahrger is the easier and simpler way to go and honestly, the losses are not really an inssue unless you are already maxing out your charge system which is not good. I normally allow 10% for inverter charger losses.

[@andrewinaustintx]

Why not use a Victron Energy Orion-Tr Smart 12/12-Volt 30 amp 360-Watt DC-DC charge controller between the alternator and LiFePO4 battery to limit the charging current between the two?

[@Clarks-Adventure]

It's a current limiter that's true and you could use one to derate your alternator to keep it cool. But it doesn't charge li right, lowers your charge rate, is inefficient (it has heat sinks and fans for a reason), and it is not bidirectional. BankManager and addressing the alternator cooling directly is a much better solution but it's your batteries, do anything you like.

[@Clarks-Adventure]

You are of course free to use any method you like. Regarding not charging li right. It's about low current overcharge. Overcharge in this way doesn't immediately kill cells but it causes an irreversible slow march towards death. Nothing in the market outside of my device charges right. If this interests you I suggest you start research with Conrad's discussion on the subject at the bottom of: www.emilyandclarksadventure.com/bbms

[@fjb9234]

Legit questions here to help me better understand. Would the current path really cut off if the BMS cut out the charge and then cause the voltage surge you mentioned? I’m thinking you have other loads off the alternator other than the Lithium Battery. For instance a 12 volt lead acid to run the starter for the engine. I don’t own a boat and don’t know how the alternator loads are wired just thinking my car with its lead acid battery and the loads to run all the electronics.

[@Clarks-Adventure]

Yes I wouldn't have made a video saying yes if it wasn't true. Cars have a lot of loads running all the time. Boats are different. I've been called to repair this issue it's real.

[@tracym9142]

Keystone RV told me not to keep my lithium batteries ON when towing. Didn't seem right, since it's something I've always done with regular batteries.

[@Clarks-Adventure]

It's really easy to damage LiFePO4. Continuous charging with your alternator would certainly damage them. Lead is tougher. Really the only way to charge li properly outside a lab is currently the BankManager www.emilyandclarksadventure.com/bbms

[@tonyrebeiro]

From what I understand, you are dealing with a spike, that happens because the AVR on the alternator is not quick enough to cut exciter current. You say that the spike is about 400mS long. I have not tested what I'm going to say, on this particular case but I know it will work, because I've used it in other places to achieve the same function. You can put a 20 volt, (for a 14.8V system)80F Supercap bank in parallel to your alternator output. This setup should be able to absorb the spike, thereby ensuring that the voltage is within manageable limits. Supercap banks are capable for absorbing a good deal of energy and stabilize your DC bus.

[@Clarks-Adventure]

Yes a capacitor bank can absorb this energy. They are great at sucking down big current. But at what cost. Lead does the same thing and has loads of other benefits. One down side of caps is they can discharge great pulses of current. Say you do this and then connect a big inverter. The discharge from these caps to the caps in the inverter will cause a possibly dangerous current flow. Then you find yourself having to deal with current flow issues.

[@tonyrebeiro]

@@Clarks-Adventure No. Nothing like that will happen. Trust me. I have 35 years of experience, fooling around with these things. That's why I suggested using a Super Cap. This small 400mS surge pulse will hardly make a dent on the VOLTAGE across the Supercap. So, your explanation about the inverter and a surge etc is not relevant. Moreover, most modern Inverters have PWM based DC to DC converters on the DC side. So, if there is a small rise in the DC voltage, the input filter capacitors and converter will absorb it very easily. These kinds of 'Dangerous' current flows can happen if the voltage surges, but if the voltage is within, say 10% of the nominal input voltage of the Inverter, NOTHING will happen.

[@AdamC5013]

Does a Ballard external regulator protect the batter from BMS shutdown or you would still want a hybrid or secondary battery? Thanks great video

[@Clarks-Adventure]

You would need the second battery.

[@plightn]

How about adding a capacitor into the mix?

[@Clarks-Adventure]

It's been brought up a LOT in the comments. I'm not a fan

[@TurgutKalfaoglu]

Very interesting -- thanks! Btw, can't you have your lithiums and your lead acids connected in parallel? That way even if the lithium disconnects, you still have your lead acid connected?

[@Clarks-Adventure]

Yes that's exactly how the BankManager is configured. And the BankManager takes care of the different charging requirements of the lithium bank

[@MondoRockable]

What was the argument against using a DC:DC charger between the starter (AGM) and house (LiFePO4) batteries, with the alternator connected only to the starter (AGM) battery?

[@Clarks-Adventure]

Limited charge current into your Li and a bad charge algorithm that will most likely kill your Li in a few years.

[@Clarks-Adventure]

Also. It's a one way deal . You can't charge your starter battery from your solar. Lead lasts longer if it's floated.

[@MondoRockable]

@@Clarks-Adventure Can't the starter battery be charged by solar using an MPPT Charge Controller, connected directly to said battery (starter battery being an AGM)?

[@Clarks-Adventure]

Sure but now that panel can't feed the house bank. It's easier to just put together a hybrid battery model. It's legit (ISO just asked me to write a white paper to get them started on their new standard). Works (300 BankManagers sold) And most importantly it's the only way to charge your Lifepo4 properly in a live off-grid battery installation.

[@roncarcamo5785]

Question: if you are running Lithium for the house and Lead for the engine that are connected to a magneto (modern outboard engine) do the overheating concerns still apply? Given the continuous running nature of a Magneto do we just let the BMS do it’s job to regulate amp charging of the Lithium batteries ? Or do we still need a bank manager or dc-to-dc charger?

[@Clarks-Adventure]

You still want the BankManager as the voltage regulator in the outboard wouldn't treat the li kindly. I just don't have any experience with what happens when you remove a battery from a modern outboard so the diode protection may be unnecessary but the li charge controlled is very important.

[@Dansk55]

Very informative. I bought a NOCO lithium battery for my motorcycle. Is this scenario possible? What remedies can I use if that's the case? BZY91C18 diode?

[@Clarks-Adventure]

I dropped a little Li into my bike years ago. My bike has a 1.7 liter engine and the lead batteries just didn't last long or reliably crank it over. I've had no problems but I certainly wouldn't need 15 years out of it to feel I got my money's worth. Honestly I'm not even sure it's a LiFePO4. So what I'm saying is those are different little beasts. They live hard and I bet they will die young but in the scheme of things don't cost much. The banks of li I'm referring to in my videos cost a lot more and, in the boat case, are taken to places where replacement is nearly impossible. They have to be reliable.

[@georgecarney3083]

Hi Clark, Rick Moore from Sophisticated Lady Explained the installation of a second 48V 5kW Balmar alternator, with individual Balmar regulators per alternator and a centre fielder to sync the alternators. The output of the alternators connect to a common buss with a feed to the 48V LiFePO4 battery system. So I don't know what happens to the alternators when the batteries get fully charged? His YT video SSL667

[@DIY12-24v]

7:44 a supercapacitor bank would be cheaper

[@sgtbrown4273]

That's what I was thinking. 5 F with some heavy wires to it should be just fine.