Lithium Batteries? School Me , marine/boat applications!

trophywife

Crew Member
i want to understand the pros and cons of changing my boats over to lithium. smaller? more cranking amps? i am no sparky.
 
For starting battery, lithium isn't recommended. I think there are only one or two different manufacturers that have a factory lithium starting battery.

Here's my understanding (feel free to correct me): all Lithium batteries include a battery management system (BMS) that controls charging and protects the battery - because an unhappy lithium battery can cause a runaway reaction leading to a serious fire. When you start a large engine, a lot of things happen very quickly - large amount of current out, and then a quick change as the alternator takes over and begins to charge. This can cause a lithium battery BMS to trip to protect the battery. If the battery trips - the alternator on your engine has nowhere to dump the excess current - poof, you just fried the electrical system on your outboard.

Lead acid batteries don't have a BMS - they use the basic chemistry of their construction to act as a big shock absorber on your electrical system, If they get excess charge for a few seconds - water turns to a bit of hydrogen - no harm done (hopefully).

For an engine battery - flooded lead acid, or AGM. For house load - lithium can store vastly more energy, lasts longer, can be run down further with no damage, etc.
 
First, talk to a marine electrician and check out the youtube marine electrical series by jeff? in Vancouver? Don't listen to internet cowboys like me especially when it comes to electrical!

Dakota and a few others make Starting Lithium batteries but do your research, one on ebay by another brand did not even have a cold cranking amp much less marine cranking amps. The dakota's and others lithium lipe04 starting batteries I have seen are very expensive.

House batteries are cheaper, but you'll require a DC-to-DC charger to use your alternator to charge them, or solar array. Your existing shorepower charger may not charge them fully. New Victron and noco charge them other ones...? Look at the owners manual or sales page for your onboard charger.

Try to get one with low temp charging protection as well.

I think I can get discounts for Eco-Worthy products, which are the most affordable ones, but based on my research, I'd look at Litime for marine house batteries.
 
I installed a Lithium house two years ago and can provide my thoughts. My setup is twin outboards (300hp), each with their own start battery and a separate house battery.

Mercury is the only manufacturer (as far as I know) that approves the use of Lithium for starter batteries, specially their own brand RELiOn. Other than weight, the advantages for lithium vs AGM / lead acid as a starter are limited as the needs for a starting battery are pretty simple - deliver the current for a short period when needed. Since they are connected to the engine, they are the first to be charged so generally are topped up and ready to use. Once you meet the engine manufacturers recommended specs, there isn't really an advantage to going bigger.

The big advantage for Lithium is as a house battery as you get a number of benefits besides weight, including:

- more usable capacity. A Lithium battery can be drawn down further than a lead acid without damaging it. Generally lead acid's shouldn't be drawn down more than 50% of their stated capacity otherwise they will be damaged. Lithium batteries can go to 20% or lower without issue. This allows you to get more for a given amp-hour rated battery, or use an even smaller battery than you'd be replacing.

- "higher quality voltage". related to above, on a lead acid, as you draw down the battery you will see your voltage drop. Lithium batteries will maintain the same voltage right down until the shut off.

- less self discharge. Lead acid batteries can lose up to 30% of their charge in a month. Lithium will be 2% - 3% per month.

- up to 5x faster charging.

- Longer life, 5 - 10 years for a Lithium battery which can handle many more charge cycles.

You will have to set up a DC-DC charging system, a DVSR system that most boats have won't work. It's pretty straightforward, see below of the picture of my setup. I also added a battery monitor and the Victron app also provides info the DC-DC chargers. Note that the BMS is there to protect the battery, it doesn't manage charging.

Happy to answer any questions. I've been super happy since I switched over. I went with a Battleborn battery. Apologies for the duplicate info to what @kaelc posted while I was typing this.


IMG_4222.jpeg
 
I have been thinking about this too.

I used to just use a Canadian Tire Nautical battery for everything, cars and boats. They lasted for years but the last couple I bought only last a year or so, less lead maybe.
 
I have been thinking about this too.

I used to just use a Canadian Tire Nautical battery for everything, cars and boats. They lasted for years but the last couple I bought only last a year or so, less lead maybe.
I've also given up on Canadian Tire batteries recently. I only buy them if I need one at like 8:00pm and it's the only store open.
 
Im thinking of getting one just to run my sounder. would 30 amp hours be enough to run the sounder for a day on the water? humminbird 788
sounder is currently hooked up straight to the main battery but every time i crank the engine it freezes the sounder then i have to disconnect/reconnect to the battery to get the sounder running again. I think my main battery is nearing its end of life but is still working for cranking purposes.
 
Likely but as you add draw, with more electronics or electric reels, or do two days of fishing without hooking to a charger, it will quickly become too small. I’d go for 100ah mini with a solar panel to keep charged if you aren’t going to add a blue seas add a battery kit and a dc to dc charger. I’d get an agm from Costco first and see if that fixes the problem.
 
Im thinking of getting one just to run my sounder. would 30 amp hours be enough to run the sounder for a day on the water? humminbird 788
sounder is currently hooked up straight to the main battery but every time i crank the engine it freezes the sounder then i have to disconnect/reconnect to the battery to get the sounder running again. I think my main battery is nearing its end of life but is still working for cranking purposes.
Checked the specs of your unit, and it draws 650 mA, or 0.65 A. With a 30 ah battery you could run it for 36 hours and discharge the battery 80%
 
I suspect that when you start, you are getting too much voltage drop and its cutting out the sounder. Start by checking your electrical connections for any buildup, but a battery would probably cure the issue best - make sure it is rated for enough CCA. I bought a Costco Energizer AGM - great battery, great price, great costco warranty.

In the meantime, if that battery is on borrowed time I'd start carrying a jump pack, just in case.
 
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