Lithium Battery Upgrade

[W2ET]

Has any forum member accomplished a partial or full upgrade to lithium batteries? Starting battery, alternator, one or more house batteries, control modules, solar panel or windvane interface, inverter, monitor, etc.?

Over the years, I have had regular episodes of paranoia about not having enough energy, but everything I read seems to suggest that a conversion to lithium is much more complicated and maybe two to three times as expensive as simply swapping out batteries (which are not cheap either). That paranoia explains why my boat had a permanent list to starboard.

I'd be interested in hearing the war stories, with as much info about specs as someone might be willing to share.

Bill

[Dave Neptune]

Bill, I have many friends who have converted to Lithium Iron and are quite happy with them. I know 2 who went with the straight lithium and were not real happy with the complication of the systems once set up nor did they like the "total cost" of conversion. They were satisfied but said next time they would go to the lith/iron.

My son an avid off roader has built a super nice Lexus off road vehicle for way out there camping. He has a really nice system and uses both lead acid and lith/iron. The SUV came with a glass mat battery which he still uses for the truck/start. The alt charges both systems when the engine is running as both batteries charge almost the same. He uses solar to keep the lith/iron running the fridge/freezer when the engine is not running. The solar is isolated to the "house system" IE fridge outside lights and a small inverter to charge cameras and phones etc.
I'm not sure of how it is switched but it is with a controller that does accept the alt charge and carries it to the lith/iron and the start battery. It regulates both batteries separately. He has had it for a few years and absolutely swears by it.

I used AGM's as they gave me 20~25% more usable power that the straight lead/acid deep cycles so the cost per watt was not that much more. The same goes for going from AGM to lith/iron where you gain another 25% of usable power.

I was going to convert to a similar system as my son using a small AGM for start and lith/iron for the house however I sold the boat and moved to Grand Lake O the Cherokees where I now have a couple of power boats.

Dave Neptune

[joe_db]

Has any forum member accomplished a partial or full upgrade to lithium batteries? Starting battery, alternator, one or more house batteries, control modules, solar panel or windvane interface, inverter, monitor, etc.?

Over the years, I have had regular episodes of paranoia about not having enough energy, but everything I read seems to suggest that a conversion to lithium is much more complicated and maybe two to three times as expensive as simply swapping out batteries (which are not cheap either). That paranoia explains why my boat had a permanent list to starboard.

I'd be interested in hearing the war stories, with as much info about specs as someone might be willing to share.

Bill

I looked into it and I decided doing it right cost more than I wanted to spend.
I may still do it, but there is a LOT more to it than just a battery. Don't forget a better battery is a better storage tank. It is not going to help you if you use more electricity than you generate, you will still run out.

[msmith10]

I did it last year, and it was one of the best improvements I've made to my boat in the 20 years I've owned it, next to a below deck autopilot and AIS.
However, my needs are quite different from the usual cruising demands. I participate in an annual 300 mile singlehanded race. I use 4 amps/hr while racing. Deep cycle lead acid batteries were a constant PITA during this race. I had 2- 100 amp hour deep cycles. After 24 hours I'd have to start running the engine to recharge, never got the batteries back to a healthy state, and every time I had to recharge there were diminishing returns, to the point where I would have to charge every 4 hours or so. And, after the first 24 hours, I was never getting 12 volts out of them.
Last spring I got a good deal on 3 - 100 amp hour lithiums and swapped them out for one of my lead acids. Saved 25 pounds net and gave me 6 times the usable power. This year I did the whole race (65 hours) at a constant 13+ volts without needing a recharge and still had 30% state of charge left.
I simplified the installation by keeping 1 lead acid for starting, and my lithium house bank is not connected to the alternator charging system. I charge them from shore power (the starting battery is still on the alternator). However, it wouldn't be that hard to add them into the alternor charging circuit if I want to in the future. Probably about $300 additional expense.
There is some research you need to do, but the rabbit hole isn't that deep. Compass Marine (Maine Sail) has a wealth of info on their site. The advertised "drop in replacements" are not. You don't want to use Lithium for a starting battery as the large current draw could trigger the battery management system to shut the battery down, and you don't want to connect Lithiums directly to the alternator, as again, if the BMS shuts down the batteries, you'll fry your alternator diodes. There are also special fusing requirements (class T fuse) for Lithium batteries due to their ability to provide a huge current flow.
Costwise, for me it was a no brainer. Total cost of my project was about $1200 for 300 amp hours, charger, necessary fusing and wiring. My deep cycle lead batteries are over $300 each now, and the way I use deep cycles, I only get about 3 years useful life out of them. Purportedly, I can count on 2000 cycles to a discharge of 0 from the lithiums. I'll most likely be gone by the time my Lithiums are no longer usable.
So, although my usage is pretty specific to me, even if I were primarily cruising, I'd switch to lithiums in a heartbeat, but I'd go the extra step to incorporate the batteries into the alternator charging system, and if you have solar or wind generating capability, even better.
I do want to thank Edward C, a frequent poster on this site, for his help explaining some of the wiring best practices when I did my install.

[Dave Neptune]

Mark, are you using lithium ion or lithium iron phosphate?

Why are you hesitant to use the lithium to start? They are very capable of flowing more than enough current to start the A-4 or even a small diesel.

Dave Neptune

[msmith10]

Dave,
I am using Li-Fe-PO4. Less energy dense than other chemistries, but no tendency, or at least far less, (I haven't found any examples) toward thermal runaway. I read that Tesla is going to Li-Fe, at least in their less expensive (relatively) models, although that may be a function of cost rather than safety.
You're correct that the Lithiums are more than capable of starting the A4. In fact, they're capable of such huge current flows that special fusing (type T) is required with high (10k amp) interrupt capacity, in case of a short or other sudden large outflow. The problem lies in the battery management systems built into the batteries. They monitor, among other parameters, output current. Mine allow a max output of 100 A, and 350 peak (for 3 seconds). Although it's unlikely that that you'd exceed 100 A starting the A4, if it did happen, and the engine started, then the BMS shut the battery down, the resulting power spike would kill the alternator.
Another problem is that Li-Fe don't like charging voltages as high as our alternators are putting out. Mine specify 14.1 volts, so charging Li and lead at same time poses a problem (easily overcome- below).
In addition, I kept a single deep cycle lead battery in the system in case I wanted the ability to charge from the alternator in the future. This requires connecting the Lithiums to a lead acid battery via a DC-DC charger which regulates voltage to the Lithium batteries and also provides a safety in case of lithium shutdown- the lead battery serves as a sink to protect the alternator, and the DC-DC charger steps voltage down to Lithium's preferred level. It also enables you to set up a charging algorithm for the Lithiums (basically they only need a bulk charge phase- no absorption and certainly no float phase).
For my usage, it was just easier for now to leave the Lithium house bank separated from the charging system, and as long as I have a lead battery on board, I'll start from that.
I do have friends who have eliminated lead altogether and have had no problems starting their diesels with Lithium, but the manufacturers do not recommend it.

[joe_db]

Mark, are you using lithium ion or lithium iron phosphate?

Why are you hesitant to use the lithium to start? They are very capable of flowing more than enough current to start the A-4 or even a small diesel.

Dave Neptune

The kind of lithium batteries I would be willing to be in a confined space with are not necessarily a good idea to start an engine. The BMS on the cheaper ones is rated for 100 amps frequently and the starter draws 130 amps or so. The better batteries with 200 amp BMSs are in spec, but you are running a large inductive load through a bunch of transistors, which is hard on them.
The other issue is absent a lead battery backup, if the BMS croaks for ANY reason you are now dark ship with no warning, no way to fix it, and the alternator is probably toast.
If/when I do add lithium batteries, they will charge through a DC-DC charger off the start battery.

[msmith10]

Agree, Joe. I bought highly recommended (Kilovault) batteries. They have an American made and much more robust BMS than the cheap Chinese batteries. I got them for $250 each which is less than half the normal price and less than the price of cheap Chinese batteries so I was very lucky there.
The BMS settings for the Kilovaults is stated above, and these are high quality batteries. Kilovault's literature advises not to use as a starter battery and I don't ignore manufacturer's advice in most cases.
A lead battery for starting, then charging the Lithiums via a DC-DC charger via the alternator is the right way to go for most people and I will probably end up with that just for versatility, but I have no reason to do it now. But it's an easy and pretty cheap project so it won't take much to motivate me to do it.
I usuallly take on 1 major project or expense per year on my boat. Four years ago a laminate #1; Three years ago, a new main; 2 years ago a new bottom. Last year the batteries. Been doing that for 21 years on this boat, and it's just how I want it. So unless I come up with some other project for next year, it may be that.

[sastanley]

Not sure if y'all are familiar with Rod Collins. He has had some recent health complications, and he is quite wordy so it takes some time to get thru his articles, but his knowledge seems sound to me.

I really think his goal is education from his own experience, and some affiliation with ABYC, and then let you decide what you want to do. He does get some commissions if you click on his links to various vendors, which is fine with me.

On the sailboat, I was running a laptop, charging iPads and cell phones, so lead acid worked out OK, but now I have some amenities like refrigeration, and maybe wouldn't it be nice someday to cool off the cabin for a couple hours with onboard A/C off the grid via an inverter with enough battery amp hours to power it? Who knows...I am not there yet...but I am keeping an eye on the tech.

LiFePo4 seems to be the most stable for now.

I am gonna guess based on Mark's comments, he knows of Rod, or has read some similar articles. Here is a link to Rod's site if you want to get into the weeds. https://marinehowto.com/

[msmith10]

I sure am familiar with Rod Collins, Shawn. He's goes by the moniker of Maine Sail and I referred to him above. He's on a committee of the ABYC and helped write the rules for lithium batteries that came out maybe a year ago. I really trust him and respect his opinions, which always have a sound basis. A real refreshing concept these days. He is a really good source for knowledge on lithiums,

[sastanley]

Mark, agree, 100%. I missed your reference, but the stuff in your post sure made me think of Rod and his knowledge.

[W2ET]

This is really informative!

In a "simplest" approach, where the house battery is the primary target for an upgrade (and as few other items as you can manage), can I feed a reasonably sized DC-DC converter with the high output alternator without overwhelming it?

Is the starting battery the first mouth to feed when charging?

I didn't know you could retain a non-lithium battery for starting.

I learned prices for the new hardware are all over the place.

etc.

Tnx for all.

Bill

[joe_db]

The best "easy/cheap" setup is the engine starts off the lead-acid battery and charges the lead acid battery. The DC-DC charger connects the engine battery to the lithium house battery. The DC-DC charger provides the correct charging voltages for the lithium battery regardless of what voltage the engine battery is being charged at. The DC-DC charger also puts an upper limit on the demands on the alternator. A lithium battery can charge at such a high rate it can look more or less like a dead short to an alternator if directly connected.
Another large benefit is if the BMS trips offline, the alternator is not destroyed. It still charges the lead battery same as ever.
See

https://www.amazon.com/Victron-Energy-Orion-Tr-Non-Isolated-Bluetooth/dp/B086Q8YNJZ/ref=sr_1_2?crid=2R7WXPF66B71F&keywords=victron+dc+to+dc+charger+12v&qid=1696509874&sprefix=victron+DC%2Caps%2C98&sr=8-2

[joe_db]

Float charging destroys lithium batteries, as does just sitting at 100% charge.
The shore power charger should charge them up and then either turn off totally or switch to such a low float voltage that the batteries can drift down from full.

If your boat just sits that is one thing, but if you like to leave shore power on to run pumps, a fridge, and so on you need to take some care. If I do this, I am going to get a power supply/charger I can adjust and run it at something like 13.0 volts in float to support various loads without damaging the batteries.

Even more to keep in mind, lithium batteries cannot be charged below freezing. The BMS "should in theory" cut them off at freezing, but especially with Chinesium batteries that is not certain even if the battery says it will do that. You can get heated batteries that when charged in the cold will run a heating element until they get warm and then start charging.

Last fun fact, some boat insurance policies are void unless the batteries are American made and installed by an ABYC certified tech. Even then at least one company splits a hull loss 50/50 with you if it is related to batteries.

[W2ET]

Joe:

That Amazon link you posted has a nice schematic. How do you integrate shore power with it?

Bill