Can A Lithium Battery Fry Your Alternator?

Are you interested in putting lithium batteries in your sailboat? Understanding how lithium batteries work and charge is important because lithium can damage your alternator or sensitive electronics like chart plotters, or cause a lithium fire. How to charge lithium is a big question because your sailboat battery charger may not be compatible with new batteries. This week we cover DC to DC chargers for your boat.
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[@UncleJoeLITE]

I guess there's a good reason I just bought a new lead acid battery for my sports car...thanks Tim.

[@gonesailingw]

I strongly disagree with using DC/DC …… it kills one of the main advantages of Lithium batteries…. In the video you showed using a Victron DC/DC with a 20 amp output!!! I expect to be able to charge a lot faster than this. I find the following works well: • Alternator charges wetcell start battery (this avoids the problem of a sudden BMS shutdown). • Use an external regulator with a temperature sensor to the alternator (eg balmar)… this protects alternator from overheating. External regulator will throttle the alternator and prevent burnout. • Use a voltage sensitive switch such as the Victron Cyrix Li-Ct to share charge between the start and the Lithium. The Cyrix unit is designed like an ACR except it is programed for lithiums. With this one can take advantage of full alternator output. The Cyrix Li-Ct comes in several different sizes (up to 250 amps if my memory is correct). - Wet cell batteries like to be charged at 14.4 volts, so do most of the 12V Lithiums that I see on the market. Therefor wetcell and lithium batteries can work together. Wes

[@TheGirmann]

Never really thought through all of these issues at the same time. Thanks for putting it all in one place. There are multiple electrical solutions to all of these potential issues, but none of them exist today. These might include "smarter chargers" that understand how to shed loads when connected to an alternator. There's clearly a need for better regulators attached to the alternator that could accept and dissipate the voltage spikes caused by connecting a lithium battery connected directly to an alternator - think about a surge suppressor, but for your boat.

[@apollo8352]

Because lithium batteries voltage does not really rise much until they reach full charge... the standard old car alternator is not designed to deliver such high prolonged currents and can burn out, especially at lower revs. Most people use an expensive DC to DC charger to limit the prolonged high current.... but a simple and cheaper way is to use a long length of cable with high amp rating as a resistor... make sure the cable can hold the amps and then add more cable length to limit the charge current to about 50% of your alternator rated output. I'm an electrician and have been using this set up in my motor home for years....the old K.I.S.S. principle!

[@diegomestrecam7674]

Im Using a special alternator for LiFePo4 from Electromaax. It is rated for 165A but has the diode rectifier in an external heat sink with active cooling and a smart regulator which is attached to a shunt. So it monitors the Alternator Temp, battery temp and voltage, and charge current. So I set up the parameters of the smart regulator in a way that never overcharges the LifePo4 and also do not overheat the alternator. is like a BMS for alternators

[@artsmith103]

Interesting. At the moment BMS stops taking charge, what happens?

[@gstoddard1325]

Don't complain about free opinions. Nothing is black or white when it comes to systems. it's a system. Make your own perfect video about all systems in every charging scenario. We need to not be negative and lift up the passionate people. Keyboard warriors. Get a boat.

[@ethanbarr4475]

You are scaring ppl, victron XS has the ability to limit current drew and detect when an engine is running or not, you can even program the start and stop voltage. There are other products that can do that too. I guess what I am saying is that a concern is there but also the solutions. Like everything, if you don't know what you are doing, it'll be expensive and dangerous.

[@kenchace8444]

Thanks. Tim, that was an extremely clear description of the ins and outs of going lithium.

[@NaptownPete]

I'll never put lithium in my boat. Too expensive, and the risks outweigh the benefits IMHO.

[@STRUTZKOFF]

what do you mean ? they are cheaper . and they are safer. there are no confirmed cases of lifepo4 fires.

[@RustyKnorr]

Absolutely agree.

[@TimAch-p2c]

I speculate a small solar panel to top-up the Lead start battery might trigger the DC to DC charger with its 30 or 60 amp draw for the lithium. Similar problematic results. First.

[@todddunn945]

This isn't an issue with a quality DC:DC charger like a Victron. Why? The Victron DC:DC chargers shut off when the source battery (Lead Acid) drops below a threshold voltage. That voltage is adjustable. So you can set the DC:DC charger shut off voltage at say 12.8 volts. That will shut off the DC:DC charger if the charging source for the lead acid battery is smaller than the DC:DC charger's output and the lead acid battery drops below the shut off voltage. This shut off voltage is normally used to shut off the DC:DC charger when the engine is shut down, but it will work in the scenario Tim described. Another thing is that you want to size the DC:DC charger to have no more than half of the alternator output so the alternator can keep up with the DC:DC charger even at low engine rpm.

[@garymiller7870]

I use the approach you outlined using a 120A alternator, regulated with the Balmar MC614 (w/alternator temp sensor) to a lead acid 12V starting battery. When the starter battery voltage exceeds the setpoint voltage, two Victron Orion XS 12/12-50As charge two SFK 300Ah LiFeP4 batteries in parallel up to the recommended 60A+/-. After 6mos of moderate use it is working well. Using the alternator/starting battery design not only protects the LiFePo4 batteries and the alternator but also the engine ECM. Dual Orion's provide redundancy and with reversible plugs can charge the engine battery from the LiFePo4 bank. Adjusting the Orion settings I was able to control the starter battery load and change the LiFePo4 charge profile. This helps to avoid long hours of holding the LiFePo4 at 100% SOC which is thought to diminish LiFePo4 life. For my batteries a full charge is only necessary every few weeks. Although I rarely charge the starter battery from shore power the Orions are wired to only charge when the ignition is on. The XS version is much more efficient then the previous model and I don't use very high current so I've not experienced a heat problem. The only concern I have with this system is at 1000-1400 eng RPM the Orions demand too much and the alternator over heats. The Balmar regular steps down field voltage at a case temperature of 100°C but if that failed it would fry my alternator; A single point failure. I have yet to exhaust the programming options. Another solution is to step up the alternator or switch to the Acer Zeus regular which can limit current at different RPMs; although it requires more complex wiring and expense. Thank you for your article. This is a great subject with much to learn. I choose this approach because I like the active control and visibility provided with Bluetooth. I find the passive systems very interesting and appreciate the strategies.

[@eliinthewolverinestate6729]

Didn't we have this problem with car amplifiers? And dimming lights when the base hit? Same solution a super capacitor bank. Super capacitors increase system runtime in marine vessel applications has gone from 30 minutes to 2.12 hours with battery only compared to battery plus super capacitor. You have solar and 4 batteries an ac inverter and a circular saw. You ain't running that saw all day. Same solar panels 2 batteries and 2 super capacitors and your running that saw almost all day. A super capacitor bank will cycle instead of your batteries and fully charged in seconds. Which means more cycles out of your batteries making them last longer. Lithium is not renewable and earth only has 88 million tons and about a quarter of that is what we can actually get too. Plus no more hard cycles on your batteries. Capacitors with power coming in can do a constant supply from solar. This works better if using only d.c. devices. In short super capacitor banks provide higher voltage but discharge fast and charge fast. Batteries provide low voltage but discharge slowly and charge slowly. Together they make a good solar d.c. system. It's like a soft start built into your solar system. Protecting battery anodes from cycling and hard cycles. Of course why would battery companies want your batteries to last longer? Eaton makes huge super capacitors for ships. It helps on size of wiring needed and battery weight. Which means also your alternator last longer. Because not taking as much out of your batteries when they do cycle. Gotta discharge the super capacitors to work on bow thrusters on newer ships.

[@Jumbo-D]

Apparently this You Tuber has never heard of an external alternator controller. Do your own research on lithium batteries, there is much more to the story than what you are hearing from this video.

[@gstoddard1325]

This KZbinr is making general videos for the masses. I would definitely enjoy a detailed video on the finer points. Clark's adventures make several videos about everything to do with charging and lead and lithium systems. He also made a battery doctor? It regulates lead and LiFePO4 together. Be positive about educators, it's easy to point out flaws. But the negative pointers are not making videos. Like chasing latitudes, not sailing that I have seen, just pointing out things negative. We need to start pointing out the people doing positive things. Not the flaws of them.

[@thedolphin5428]

Agreed. And there is no DC-DC (over 60A) which can do justice to the current that a LFP COULD refill if connected directly -- with, of course, a decent alternator and a surge protector.

[@ArgusBrown]

@@thedolphin5428 Mastervolt makes a 90A DC/DC Li-ion charger

[@svDansleau]

I've installed an APD ( alternator protection device), mine is by Sterling and I think Balmar makes one as well. I also switched out my Alternator that has a smart external regulator that know how to charge a lithium bank. If you have a high amp alternator say 200 you will need to buy many dc-dc chargers to move all those amp over while losing effectively and producing heat. SV Sandii

[@dsanner]

APD seems key whenever the alternator is connected to lithium, even with smart chargers and/or communication. With a large alternator this make sense and then just add a small DC 2 DC charger to keep the starter battery topped off and this direction works better as it requires less/little use. If the lithium goes offline you can have emergency backup by just paralleling the batteries / switching house loads to the starter battery.

[@sveoti]

Same here. I have the Balmar APD, and Balmar regulator. That all protects my 170 amp Balmar alternator. I have to be careful if I run my gen set the 200 amp battery charger will also turn on and if my Solar is all going that’s another 200 amps. This all dumps into a main Lithium bank that has a dc to dc charger for the start battery.

[@colinritchie1510]

Fascinating insight Tim...thank you for this!

[@michaelbrockman6830]

Shore power typically runs a battery charger. On older (read before Li Batteries) boats, the chargers are set up for lead acid. You will need to change these out if you go to Lithium. There is another solution which DOES NOT NEED a DC to DC Converter .... First .... Make sure you have two (2) battery banks by removing the standard Bat 1 -> All -> Bat 2 switch and by either adding two separate switches or replace with a dual circuit switch ... Second .... Remove the old battery charger and replace it with a charge/inverter combo ... Connect the Charge/inverter to shore power and the lithium battery bank .... third - connect the old battery charger to the inverter (and to the lead acid battery) ..... and if you have solar - connect that to the lithium bank ..... You now have the best of all worlds .... Shore power charges lithium bank .... powers inverter which powers lead acid charger - which charges lead acid bank .... Solar recharges lithium bank which as mentioned can also recharge the lead acid bank via the inverter .... and while on shore power -> the charge/inverter can feed the lithium as quickly as possible (mine can go as high as 100 amp charge) I can go into detail (write an article with pictures) as I made these changes to my Catalina 270 just recently ...

[@SAILINGDIRTYBIRD]

What about a "cheater box"??? I use a "Sterling box" in my string...is that good enough? I also use a Lead Acid as my starter with 4 - 100 Amp Hour Lithium Ion (pho) ???? Any thoughts?

[@svDansleau]

Is your Sterling box an adp

[@SAILINGDIRTYBIRD]

@@svDansleau Sterling BB 1230 -12volt 30Amps...A B2B unit...allows Lead Acid to Charge alongside Lithium Ion (Life PHO)

[@nicomakris3485]

I have a 170A Balmar alternator connected to the Lead acid starter battery. Then a Sterling 120A DC To DC charger going to 450Ah Lithium. Advantages: 1) the alternator is never asked for more than 120A. 2) The Sterling DC to DC is rated more than 95% efficient and never heats up. Had this setup for 2 years now - very happy - lots of power!

[@SAILINGDIRTYBIRD]

@@nicomakris3485 nice 👍

[@GreatCreative]

Sounds like a job for a professional.

[@WillN2Go1]

So here's what I got from this video: Lithium batteries are great but can burn up your alternator ...talktalktalktalk.... Lead acid batteries won't do this.... talktalktalk. Not criticizing. My take away is: even though I have this amazing ProSine 2.0 Inverter.... if I should decide to go from my glass mat batteries to Lithium... make sure I work with someone who really knows this stuff. Pay extra for this. It's worth it. Thanks Tim. (And often when I reach the point I'm going to change something I'll re find a video like this, rewatch it more carefully, take notes. Good resource.) One thing that constantly frustrates me as a boat owner. Most of the systems are complex, often there are more than one company's products involved, and many of the companies (B&G.....) just never respond to any request for help or to even answer a question. I would love to contact the company that sells the lithium batteries you just did a video on, or Battle Born and say, 'This is my system, Prosine, alternator, etc... can you tell me....?' I would expect to get 'Oh yeah, no problem,' and it might be, or it might not be. (Our new dock boxes were totally screwed up. The GFIs kept tripping, alarms sounded for almost a month. We were first told to get new shore power lines, then we were told we needed to get an electrician to analyze our wiring.... Then I unplugged from the box and with no load it still tripped. We could've spent thousands of dollars and it was just the new dock boxes. They were still blaming our boats when my neighbor and I plugged into an empty berth on the other side of the gangway.) How about this for videos. I've got B&G but only the chartplotter and radar. Many many things don't work on the chartplotter mostly because I'm not running up to date instruments. Speed and wind, sure they're not connected but why can't the radar track a target? I know there are all these 'other' components that B&G would sell me, but they never ever say, This is what your system should include in order to.... So maybe do the major manufacturers and describe all the components that are needed. (I'm sure if I went to Annapolis I could get this explained to me. ) And maybe some videos comparing B&G, Ray Marine, Garmin, etc... (I've never been on a boat with current Ray Marine, only B&G. 'Everybody says,' B&G has all these 'features' for sailing.... but are they things that I would actually use? That multileg calculation stuff looks cool, but I've never seen anyone bother to use them. I've got at least four months of round the clock sailing with B&G stuff. ) How about NEMA2000 and the adapters to the old 0813 stuff. They're for sale, but again, I've never met anyone who's used any, never found a good in depth message in the forums mentioning using them. With GPS, Predict Wind and Starlink sailors are never alone anymore -- until they're fixing something or trying to figure out why something isn't working or what they need to do next.

[@ArgusBrown]

That is one of the dangers of buying a "drop-in" Lion replacement battery. As others have mentioned, it is possible to design a safe system that uses can utilize the full capacity of the alternator. I feel the author should have touched on those points.

[@SalingSamantas]

All Clark's does is literally link the batteries together when their voltages match and when the lead drops too far it disconnects so they're literally part of the same battery bank and And with lithium rises too far it disconnects on the other end. So those batteries are helping each other all the time. You can only Link lead and lithium together when the batteries voltage is perfectly matched. The other thing is battery maintainer does is it has a much more lithium friendly charging profile designed into it. There are no chargers on the market, at least at the time of his making the battery maintainer that have a true proper lithium charging profile so you're not getting the most out of your batteries

[@eliinthewolverinestate6729]

Texas instruments makes them.

[@brotherwind5015]

Excellent video. This was extremely informative especially because I'm looking into lithium and knowing there are specific problems. Thank you. As always your videos, Lady K and Practical sailor, are very helpful and explained very well. Grateful I found your sites.

[@jimduke5545]

You describe an approach, but not the only or even the best approach. Take a coastal cruising C42 with a 20kWh battery bank (I know you only think in 12v and amp hours so this would be 1600ah in 12v, but we use 24v alternator and house bank) It would take 6.4 hours to re-charge a 20% soc battery bank using 4 (four!) parallel 50a 12v dcdc (Orion XS) chargers. I don’t have 6.4 hours of motoring with at least a 200a 14v alternator. The standard 80a hitachi can only give about 40a when hot A much better solution is to use a high output alternator (5kW-oops, 360a at 14v, or 185a at 28v, or 90a at 56v…BTW, 160a 56v alternators are easily sourced) with avalanche diodes and use a Wakespeed or other high quality external voltage regulator with temp and current monitoring to prevent the load dump. Add an alternator protection module (think of it as a seatbelt-it protects the alternator should there be a failure such as an ignition key turned off by toddler, or an electronics failure in the regulator or BMS). Then use the dcdc charger to keep the starter battery topped off.

[@jefflaydon3381]

My head just exploded from too much knowledge, think I will go back to sailing a Snipe.

[@davidbrayshaw3529]

This a very nuanced topic, with all number of factors to be considered and factored for in designing a system. The consequences for getting this wrong don't stop at a failed alternator. Even if you're handy and can install a system yourself, don't kid yourself that you've somehow magically transformed into an electrical engineer because you understand Ohm's law and it's only a low voltage circuit. Seek advice from a suitably qualified person before you modify any electrical system on anything.

[@jbbbda]

My Renogy 50A DC/DC charger appears to vary charging output based on input and where it is in its charging profile. I don't see it pulling more amperage from the start battery than is being produced from the alternator. This unit's output can be adjusted to 20, 30 or 50A. With it set at 50A it rarely produces 50A because my outboard's alternator can't always spare 50A, set at 40A it runs at a steady amperage. Late in the charging profile it produces less amperage. I can monitor start and house battery charging rates and have not seen the full-rated amperage draw you warn of occurring. Solar inputs convert whatever is available, I have seen as little as 4 watts produced.

[@artsmith103]

Are your solar charge controllers connected to the lead or Lithium batteries?

[@jbbbda]

@@artsmith103 The Renogy DCDC charger is also a solar mppt controller. It prioritizes start battery, then house.

[@leonardbertaux6897]

Yes, fried a nearly new high out put alternator, xt 170 from Balmar. The tech is still far from 99% reliable. I will carry spares henceforth.

[@leonardbertaux6897]

My system has lithium house bank connected to the high output alternator, using external controller Wakespeed 500, supposed to protect the alternator but in my case failed to do so.

[@EngineerK]

​@@leonardbertaux6897what did wakespeed have to say?

[@keeldragger]

It's worth noting that Balmar, Sterling Power, and others make alternator protection devices to protect your alternator against sudden BMS disconnect (or someone flipping that red switch!). That being said, I prefer having a lead acid battery in the mix.

[@stanleybest8833]

Hold on there. The first half of this episode is jibberish. You can't start explaining lead batteries and charging systems and alternators and generators unless you understand them right from the beginning. You don't start in the middle. How would I charge a lithium battery? With an alternator and a suitable regulator, but maybe a great big resistor if necessary. Blowing out gear with voltage spikes? Yes, some systems will do this and some don't. The biggest curve ball you will deal with is whether your alternator or generator is controlled by a Zener Diode electronic regulator or if it's controlled by points and coils. The later is a Titanic mess. Connect your electronics directly to a battery, and not a goofy one.

[@SailingInScotland]

I have a Renogy 50A DC/DC charger with a Lead starter battery and a 150AH house battery. When running the alternator I have it limited to 20A to prevent over taxing my 55A alternator, never had any issue even at low revs for extended period. I also use a 5A AC charger when at shore to keep things topped up. The renogy limits the charger current to the lithium to the 5A that is being provided, so no problems on AC.

[@grantlandthomas]

I’m using an echo charger between my AGM house and Lead Acid start battery. Works like a charm. I don’t need lithium just yet.

[@davidlawson5937]

Wow, lots to consider. Is it better to just stick with lead acid? Kinda sounds like it's cheaper but less efficient. Great vid! Thanks!

[@gregames897]

My Bene 393 had the start battery hard wired to the alternator, and a battery isolator relay which connected the house bank to the start battery only when the alternator was doing its job. That should take care of the BMS cutout problem if the house bank became lithium. But it would still potentially have the overheating problem. I don't like the idea of the inefficient DC-DC echo charger between the alternator and the house bank. What about a smart external voltage regulator for the alternator? Seems like that would take care of the loss of efficiency. Of course my dream voltage regulator would be smart enough to do the Right Thing for the lithium house bank.

[@ferencluki]

The charging mechanism of lithium and lead acid batteries are vastly different. Lithium batteries require a constant current charge up to certain percentage, and after that go into float mode. Alternators provide a constant voltage charging system and lead acid batteries can handle that although not ideal. Therefore charging lithium batteries with the alternator is very damaging and not efficient or recommended. With batteries is required a dedicated charging system fed by the alternator.

[@Sorkvild]

In case of a battery shutoff, yachts can employ energy dissipation systems, similar to diesel-electric locomotives. Put either a bank of resistors for heat dissipation or LEDs for light and have all the excess energy on that circuit.

[@davewiker5510]

I use Balmar's external regulator to charge the lithium house batteries and the battery-battery charger to charge the AGM start battery. Then I get full charge on both. Yeah a bit more $, but I want all charging to one battery bank.

[@williamSailingWindDragon]

I have this setup on my Cat with Electromaxx high output alternators (140 x2) and their regulators. Also use a third DC-DC to charge my Windless battery.

[@artsmith103]

So your solution is put all your money and technology in charging the Lithium and then give the Lead a little basic charge as necessary.

[@hans-verhoeven]

I'll stick to proven technology of lead acid. And on 22 metric tons the weight is hardly an issue.

[@STRUTZKOFF]

it can, but it also can work very well i do this often ! i am a balmar installer, most boats have 3 kw altenators, and installing two 3 kw on cats. i am now installing a 9 kw altenator on my bayliner ! i have helped many people setup lithium systems, and use on original altenators, a trick is to use move the voltage sense wire of the alternator to the positive post of the alternator, on most boats now i set the alternator to charge the lithium house battery directly and have small dc-dc chargers to keep the start batery. a typical 12 volt altenator outputs 14.2 volts this is actually the ideal voltage for the lifepo4 absorption voltage. and is identical to lead acid ! on a typical yacht that runs less than 70 hours a year a direct alteantor to lithium is totally fine, for heavy duty cruisers the bms can tell the alternator to turn off . i posted a video a whole back of a honda 4 hp engine connected to a 100 amp delco remi altenator, with booster cables and disconnected the wires many times on video and the alternator hasn't blown up. that little generator has been used since 2001! so will a alternator burn when connected to lithium ? well depends which model, and how its wired. its very easy to overcome for the diy guy. the external regulator better yet.

[@JamesMeyerArt]

I installed a balmar controller on to my alternator - it is very hard to adjust but once it is set you can set it to delay the charge until the engine is warmed up- you can adjust it to charge lithium, AGM, or lead acid.

[@TheCornucopiaProject-bd5jk]

Using a cheap 20amp charger is the problem in your example. That’s not a proper shore power connection to also charge a housebank. You’d be better off having high quality inverter/charger connected to your lithium battery and then let the dcdc alternator charger trickle charge the starter battery. The ultimate problem is that people as all chargers are the same, all batteries, all cables, all outlets. If people don’t know what they are doing they risk burning their boat down. Unfailing around often is not helpful because everyone is an expert with little knowledge. I’m all for DIY, but look up the info first.

[@pduffy710]

At the Spring Safety at Sea seminar @ Rogers Williams, we learned that if a lithium battery bank caught fire, few of us have the proper extinguishing agent aboard and it will burn hot enough that you won't be able to eject the batteries overboard. This situation was described as an abandon ship event. Perhaps a video covering those issues would be helpful to your viewers.

[@svgrateful6715]

How does an LFIPO battery catch fire?

[@davidbrayshaw3529]

Interesting. Did the course material detail the dangers and methodology of dealing with different chemistries? Lithium Iron Phosphate batteries do not oxidise in decomposition like NCM and other chemistries do, and should be able to be extinguished by conventional methods such as dousing with water. This is one of the beauties of this chemistry, from a safety perspective. NCM batteries, on the other hand, cannot be extinguished as is now all to readily being seen due to the proliferation of EV's with NCM batteries catching fire here and there.

[@davidbrayshaw3529]

@@svgrateful6715 From my reading and understanding of the chemistry, LiFePo batteries are pretty immune to the fire risks from a chemistry perspective and the cathode/anode materials that they use. They are low resistance devices and are not prone to thermal runaway events as a consequence. That said though, physical damage to the cells, overcharging, short circuits and charging outside of the manufacturer's temperature range may result in fire.

[@stans3920]

There are a lot of design considerations. I have been trying to find some good design source, but mostly only sales stuff where there product is the answer.

[@BulletproofPastor]

Why would you install a new battery system without an appropriate charge controller? Lithium charging is very different than lead/acid. Good video.

[@stevezelen4651]

Great way to explain the difference in charging. Thanks for the follow up. 😎

[@davidblackburn3257]

Dear Tim, this video is worth its weight in gold!!! Thank you so much.

[@justice17250]

Keep it up really good job explaining it thank you

[@boblivingston4841]

I will stick with the AGM batteries.

[@TCGE08]

Wakespeed alternator regulator?

[@jackchamberlain5993]

nicely explained Tim , thanks

[@japc4326]

I'm still not sold on Lithium just yet, more so on a cruiser sailboat. A day cruiser it might make sense, but so many fiddly issues does it make it worth it? The power you get with a Lithium setup is of course plentiful and the recharge rate is much faster too but have an issue with a BMS or a fried Lithium offshore or a remote destination and you might be stuck trying to find a replacement. I also just might be too old to change what works for some new fangle gadget. Great video and gives a simple explanation on power load charging and sharing with an alternator. John

[@EngineerK]

This is one reason to diy your lithium bank, carry some spare cells and BMS(s) so you can fix it yourself. Lots of battery box kits on the market now

[@mfournier12]

Connect the alternator to your start battery and then use a dc/dc charger to send power to the house bank. This isolates the lithium from the alternator and the start battery and the agm start battery and dc/dc charger will always be a load on the alternator when running. When the alternator is NOT running the dc/sc charger shuts off. Eliminate the 1/2/both switch and instead have two on off switches and the one on the alternator should have alternator shut off to protect the diodes from a battery shut down. I could post when affront lithium you need to plan accordingly not just simply replace your lead acid house bank with lithium. Also. As for the bank manager electronics it’s still up for debate if mixing lead and lithium is a good idea so far manufacturers of lithium batteries have not recommended it. Another method is an external voltage regulator that monitors load and protects the diodes from overload. And putting all your charge sources to the house bank first and then dc to dc charger to charge the starter battery. But although tgia has he potential to get the most from a high output alternator it also complicates the electric system. If your still running the lower amp alternator your marine engine shipped with and your getting far more power from renewable a like solar or wind then you do from your alternator then the far simpler to put your renewables to charge the house bank use the alternator to top off the start battery and then use a dc/dc to sent extra alternator power to house bank when motoring so you can take advantage of that power to run the boat loads when motoring. And the diodes are safe as you always have a loads (the agm battery can handle the constant charging when motoring and once topped off most of the power goes to the dc/dc charger and what ever loads you have on like lights or a water maker you want to run while using that extra energy from dead dinosaurs.

[@RustyKnorr]

Did you even watch this fucking video? Thats exactly what he said, ffs.

[@facilis]

Only lead acid batteries in my boat 👌

[@richmorpurgo5554]

buy a lithium capable shore power charger and hook it to the house bank. You will not need to have one for the engine battery. AND carry a cheap Lead acid charger for an emergency and run it off the house bank via inverter.

[@artsmith103]

That solves the problem from perspective of solar keeps house Lithium charged so as long as starter battery is charged, everything is good. The perspective of the video is that sometimes the alternator 40+ amps are necessary to charge the Lithium house bank.

[@eliinthewolverinestate6729]

Some alternators and stator have internal resistors others rely on external resistors to regulate or rectify the current from a.c. to d.c. and a voltage regulator. Depending on what engines your running. The small solar electric pontoon boats are kind of cool. Solar electric sail boats actually make sense. Like an offgrid cottage with sails.

[@artsmith103]

For normal good weather, electric sailboat motor is enjoyable. In the worst weather, incapable and dangerous. Pick your poison.

[@BertVermeerSailing]

More questions than answers in the comment section. Excellent video Tim. Like others have said, I'll stick with AGM and await the next generation of solid state batteries for a sailboat application. Although there hasn't been an update (that I've seen) regarding the couple washed ashore on Sable Island in July, the suspicion is that their modified Lithium battery bank may have caught fire and forced an abandon ship scenario. We'll probably never know. Call me old fashion and overly cautious. When your EV starts smoking you can pull over and get out. Not so much on a boat!

[@jimduke5545]

They had an EV NMC battery. (yes, it’s a lithium ion chemistry). LFP is a safe battery chemistry with the correct install. Shortcuts and/or cheap will change the safety…

[@BertVermeerSailing]

@@jimduke5545 As I understand it, the motor and battery were out of a wrecked electric vehicle. Interesting side note, BC Ferries, one of the largest ferry companies in the world, won't allow damaged electric vehicles where the battery is part of the damage aboard. Not even on a flatbed trailer for transport to a repair facility.

[@natcalverley4344]

I am reading all of these comments about upgrading to expensive complexed electrical systems. AGM is safe ,can be mounted in any position and eliminates the acid issue in case of a pitchpole or roll. Standard marine alternator , cheap to carry a spare . Manual mechanical isolation switches don’t fail. With Blue water cruising the KISS principle is always best but to each his own.

[@STRUTZKOFF]

lifepo4 is very safe and safer than agm , i see agms daily with the top blown off. lifepo4 can be mounted in any direction, they are cheaper, lighter and last much longer

[@natcalverley4344]

@@STRUTZKOFF Daily ? You just lost all credibility. Short of a dead sort between the two terminals with a O cable and even then the terminals would melt please do tell. Given AGM’s don’t off gas I am waiting?

[@RustyKnorr]

Stick with lead acid, got it. 👍

[@GordonDavis-j8q]

Good video bud.

[@Smalleyster]

Thank You!

[@andyrigg2182]

I am using a battery isolator that the alternator feeds and it charges both the lead and lithium batteries separately. If the lithium circuit opens the lead is still available for alternator output. I have a temperature limiting regulator to protect the alternator from overheating

[@edkok5880]

@@andyrigg2182 Would that be with a Victron ArgoFET perhaps? I was thinking about this setup myself. Have you ever had a disconnect from the BMS while charging with the alternator? And did that go as expected?

[@andyrigg2182]

@@edkok5880 I had a victron and did not like it. And no I have not had a lithium disconnect

[@bryanbuss1045]

I really enjoy your videos but have one suggestion. I would like you to consider that there is a huge number of lake and costal sailors that can have their lives improved with simar solutions to those for extended offshore, with only slight reinterpretation. To use this video's topic and my own boat as an example, I converted to lithium three year ago. I did this for a similar reason to those you site, but because I will NEVER be more than three days away from shorepower and my boat is smaller and cheaper, different answers suddenly become much better. Solar makes no sense for this use case because it adds too much cost, complexity and requires space that is at a premium. What does make incredible sense is to optimize your electric load (leds, better fans, better inverters and pumps), increase the house battery capacity (>5KWHr on a 27') and keep engine start battery separate while converting it to the right type of lithium battery for this job (still saves space, decreases weight, increases capacity for safety margin and lasts longer, without the complexity of interacting with house battery set or risks of storage type batteries when used in engine operations duty). This is just an example of how slightly expanding who you think about consuming your content, dramatically changes the best answer. Please consider the cases for people that will always have a dock within 3 days or other situations that are small and more common than extended offshore. This will help with your mission to get and keep more people sailing... because it is more "practical". Best wishes and keep up the good work. Bryan

[@artsmith103]

Separate from your Practical Sailor comment, I think day sailers and weekenders thrive on solar. 200ah (2.4kWh) is a big battery bank. Most have 100ah, I'm enjoying 150 ah. With a little effort, my batteries are full at the end of every day though I do turn off my cooler at sundown since nothing vulnerable for just a few days. 2 50W panels, each with own charge controller costs about $300. That will fill batteries before every weekend and provide 25ah/day. That's more than additional half battery every weekend.

[@bryanbuss1045]

@@artsmith103 My challenge is on small boats that don't leave shore power for very long, frequently have no reasonable place to mount panels, panels complicate trailering with additional setup and tear-down, and move weight and windage in the wrong direction. Understanding the loads and timetables is my recommended place to start. I have 395ah of house lithium, consisting of a 280ah and a 105ah. I decreased the loads that I could, to optimize my power use. I also have a lithium motorcycle battery on a completely separate system for the engine (more power, longer lasting, less weight, and smaller size allows me to carry additional fuel in that lazarette). This set of decisions keeps all the weight low, doesn't complicate trailering, and allows for safe use away from dock up to 72 hours with a family of four (led lights, water pumps, fans, inverter, depth/speed, radios, cell phones, tablets, laptops, fridge, freezer and microwave). I couldn't put enough solar on my 27' boat to do this, particularly without negative impacts to its sailing characteristics and adding more headache to setup/tear-down. Each situation may have its own calculation, although I love solar (going to panels at my house next spring), it may not make sense for anything that is under 34 feet, doesn't leave shore power for more than 72 hours at a time, or has a trailer. ...although I get excited at the prospect of flexible solar that I could put snaps onto my folding bimini, this hasn't penciled out well enough yet either ($/watt - $complication > $0?).

[@artsmith103]

@@bryanbuss1045 Every sailboat in my marina is trailered at least twice per year. A couple 28', the majority are 22-26ft. There is no shore power and almost everyone has solar. My 26ft has 25W, 30W, and 50W panels. Virtually non issue to raise and lower mast. I have typical collection of auto tiller, chart plotter with depth, music, radio, and I don't run my cooler after sundown. My batteries are 90-100% every evening and I only have 150ah SLA.

[@bryanbuss1045]

@@artsmith103 No shore power adds a new dimension. 😀 How do you remove the panels to get them out of the way of stowing the mast? It already takes so long to rig and launch and from retrieve to roadworthy... I recoil at anything that makes this 2-3 hour process any longer. Invariably it is a long day because I've either just towed for hours, or will be needing to tow for hours. The worst loads for me are the laptops and the microwave... but these make staying aboard anchored out for a couple days so nice. The new 12v compressor tech has my fridge and freezer load totalling only 30-40 watts. Having ice in a drink and ice cream for dessert seems like such a luxury after years of dealing with soggy coolers!

[@artsmith103]

@@bryanbuss1045 I have 50W flexible panel forward of mast. Plugs through deck like coax or anchor light. The 25W and 30W are on 2 piece brackets clamped to stern rail. Remove from bracket and disconnect cable. My panels point in all different directions: up, aft, port. Probably will eventually add 30W starboard pointing stern rail bracket. Just big enough, keeps battery full all day. I use battery operated lantern for stern/anchor light. Recharge during day when house batteries are full. You could bring frozen 500ml bottles to help cooler. I certainly don't maintain ice nor run a microwave. I'm happy for the centerline weight of my batteries so even my next set will be lead. If you get solar, MPPT for over 30W is a good idea. Adds about 20% compared to PWM. You might have room for 100W forward of mast. Pay attention to panel cable directions.

[@tomcody8215]

Lithium-just say no!

[@STRUTZKOFF]

i will never buy another lead acid .. been running lithium for four years, and convered 20 boats to lithium . its changed thier lives !

[@edkok5880]

@@tomcody8215 Li-ion is not the same as LiPO4. The first are used in cars and can catch fire and should never be used on a boat. The latter can safely be used on a boat and will never catch fire. Every battery is dangerous but only if stupidly handled like using too thin wires or causing a shortage.

[@SalingSamantas]

There's a very easy solution for that problem . mixed lead with lithium battery's and used Clark's battery maintainer. Quite a few of them in use now and it working very well. It solves the problem, the lead gives the spike in power place to go when the lithium shuts down. The boat never goes dark in the first place, works great! The other benefit is the led never discharges below the level of the lithium when linked together so. They last a very long time being continually charged but the lithium. It's a symbiotic relationship, both types of batteries protecting the other. It's definitely what I'm doing on my Bob, although I'm not to that point yet on my refit.

[@Clime5LEDinc]

I have been using Clarks Battery Bank Manager System (BBMS) for over a year now and it works well. There have been a few quirks that I have learned to get around but overall, it manages all incoming power sources, well including my Balmar 170 amp alternator controlled by its external regulator. I can get reliably around 120 amps into my lithium battery bank when needed thus minimizing the time for bringing voltage levels to full.

[@scomo532]

Why mess with Li-ion batteries when Pb acid is cheaper, more reliable and far safer. Large Li-ion batteries are a fad, a status sumbol

[@artsmith103]

Just the 80% discharge is worth the price of admission for offshore boats. Over lifetime, LiFePO4 cost half as much per kWh. But none of that means anything if not safe and reliable. So the motivation for improvement is huge.

[@scomo532]

@@artsmith103 Safety is paramount on a vessel and especially on an offshore sailing vessel. Li-ion batteries are unforgiving consider the case of the Canadian couple recently found deceased in their RIB washed up on Sable Island. The husband had converted the boat to use Li-ion batteries for propulsion and domestic chores. The large bank of EV batteries was located under the cockpit. The couple apparently were forced to abandon ship is great haste as there were few provisions in the RIB. They apparently died of dehydration. No traces if their vessel were ever found. Could a raging Li-ion battery fire have been the cause of their ill fated hasty departure?

[@EngineerK]

Never trust someone who can't spell

[@artsmith103]

@@scomo532 I think adding EV propulsion on more than 5,000 lb boat is adding a tangent not relevant to this discussion. Everything you said might be correct, but that is a different situation than 200-400ah at 12V where 40amps is a big load. I would say that's the topic of this discussion.

[@scomo532]

@@artsmith103 Well, then there’s the incident of the dive boat Conception in 2019 which caught fire killing 34 people. The damage was too extensive to establish a definitive cause. However, it was clearly established the the fire had started in the vessel’s saloon where the passengers had all plugged in their cell phones to charge overnight. As you know, these are 2-4 Ahr batteries. Finally, there’s another incident that occurred close to home. A close neighbor’s family with 4 small children plugged the kids’ Li-ion battery powered toys in to charge overnight in the kitchen. Unfortunately, their smoke detectors weren’t working and the charging toys were sitting in a formica counter top. About 3 AM the father awoke with a choking cough and found the house enveloped in a pall of thick black smoke. He managed to get everyone out of the house and call the fire dept. All survived with some smoke damage and the house was saved. Once again the 2-4 Ahr lithium batteries were the culprit. So, tell me again about how safe your 200-400 Ahr lithium batteries are. .

[@natcalverley4344]

Anyone that puts a Lithium Ion battery bank on their boat is a idiot. Lithium fire anyone ? No thanks. You can blow your CO2 bottle or Halon and it just keeps burning. Sound fun when you are 500 miles offshore?

[@EngineerK]

Most people are doing lithium phosphate which is a completely different safer chemistry.

[@natcalverley4344]

@@EngineerK I will stick to AGM thanks . My sailboat weighs 40 tonnes so weight is not an issue and it gives me safe reliable performance with no surprises.

[@D-B-Cooper]

I’ve seen a couple of fires from these and a number of super yachts have gone up in flames lately. They have been charging caused but salt water incursion would be fun times.

[@davidbrayshaw3529]

That's true of NCM batteries, they type that you keep seeing burning in EV fires around the globe. But in the case of Lithium Iron Phosphate, it doesn't oxidise in decomposition meaning that conventional fire extinguishing methods are effective. That said, though, everything's safe until it isn't and there is a little more complexity with a LiFePo system than there is conventional Pb acid, and complexity is the enemy of reliability and dependability.

[@edkok5880]

@@D-B-Cooper Li-ion is not the same as LiPO4. The first are used in cars and can catch fire and should never be used on a boat. The latter can safely be used on a boat and will never catch fire. Every battery is dangerous but only if stupidly handled like using too thin wires or causing a shortage.

[@JeffreyDRein]

Lithium & green extremism probably killed SV Theros

[@jonathanlewis1352]

PLEASE don’t tell a partial story. There are many intricacies to changing to lithium batteries as well as different types of lithium batteries as well as different qualities depending on the manufacturer. You also need to consider cold cranking amps for a starter battery as opposed to a house battery or bank. A little knowledge is a dangerous thing especially when an incorrect installation can cost you your boat or worse. PLEASE DO A BETTER JOB educating your subscribers by having a better prepared presentation. A DIY installation is possible but only after a thorough understanding of the issues and a knowledgeable marine electronics professional is best consulted on a system that could have catastrophic consequences. This is not an issue to be taken lightly.

[@natcalverley4344]

@@jonathanlewis1352 The voice of reason. Thanks.

[@badplayerone1731]

I would never put Lithium batteries in a sailing boat or anywhere else. As soon as it catches fire you are done with. Goodbye boat. There is no way for you to extinguish the fire.

[@edkok5880]

That is another type of battery. LiFePO4 doesn’t burn.

[@jaysonlima7196]

Literally, NFPA says you have to submerge them for a minimum of a week, but to completely ensure no risk of reflash, it's something like 30 days of submergence. SOLAS just says to jettison the fire. Big help if its in the lazarette innit?

[@natcalverley4344]

@@badplayerone1731 I totally agree. AGM is maintenance and trouble free, recyclable and you can mount upside down down if you like. Charging systems are simple and so are inverters . The more complexed the system the greater the potential for problems .

[@edkok5880]

@@badplayerone1731 Li-ion is not the same as LiPO4. The first are used in cars and can catch fire and should never be used on a boat. The latter can safely be used on a boat and will never catch fire. Every battery is dangerous but only if stupidly handled like using too thin wires or causing a shortage.

[@badplayerone1731]

@@edkok5880 you should not just read information from the battery industry. There was a research by several UK universities that showed that LiFePO4 are not as safe as it is commonly known. And that safety is not as simple as it is said to be. They can catch fire and they can create a chemical hazard in your home or boat. If exposed to heat for example. Read the actrices on pv-magazine and franklinwh.