Upgrading to LiFePO4

jviss · Jun 17, 2020

I don't understand the "plug and play" references, either.

Do you ever go anywhere, anchor out, whatever, that gives a real-life test of capacity?

JK_Boston_Catalina310 · Jun 18, 2020

Tim22 said:
A quick question. Is it appropriate to use LiFePO4 to start the engine? Engine is a Yanmar 2gm20f.

Tim

Yes. My engine never started better and you won't damage the batteries.

That being said, some of that drop-ins have much lower C ratings and may not work. For instance with Relion they have their base batteries and then ones that are capable of starting. So read the specs on what you want to buy.

Maine Sail · Jun 18, 2020

JK_Boston_Catalina310 said:
I have a friend that reps Lithionics. Send me a PM if you want me to put you in touch. But be prepared that they are expensive. Likely over $5,000 for a 200 Ah system.

Good luck

We are a Lithionics dealer as well, but we only sell the "drop-in" form factor batteries. A 125Ah G-31 and the latest one is 315Ah with the FCC (field control circuit), just like the more expensive dual-bus OPE-Li3 system has. The OPE-Li3 is still the cats meow, we can sell those too, but for boats that use less current the Lithionics LFP's with built in BMS are about as good as it gets in a drop-in battery. (There is no such thing as "drop-in" LFP BTW, but that is what they are now referred to as..

Maine Sail · Jun 18, 2020

Tim22 said:
A quick question. Is it appropriate to use LiFePO4 to start the engine? Engine is a Yanmar 2gm20f.

Tim

Depends upon the battery. Many Chinese made drop-ins will have the BMS tank (open circuit) during starting. My own bank will start my engine with ease at 0% SoC, but I have a 500A continuous rated contactor that's controlled by the BMS. Then there are 300A 4D size LFP batteries than can only handle a 50A charge current and 100A discharge, pretty lame for LFP.. The limitiations on "drop-in" batteries are due to the FET based BMS, not the cells. Many drop-ins can't handle high starting loads and some are designed to. The Lithionics drop-in batteries can handle starting so it is always best to read the specs.

JK_Boston_Catalina310 · Jun 21, 2020

Tim22 said:
If I keep an FLA for starting do I need to change the starter wiring to always use the FLA? My current FLA system uses a 1,2,both, off switch to select which battery to use. Battery 1 is the main bank while battery 2 is a backup. I generally use Battery 1 for everything including starting and keep Battery 2 for emergencies. In a new LiFePO4 with FLA for starting the FLA would presumably only be used for starting.

Thanks
Tim

Again, this entirely depends on what batteries you purchase and what other equipment you upgrade.

I started keeping the primary bank (LFP) and reserve bank (AGM) setup. But alternator problems made me rewire as a starter battery setup with the alternator only charging the start battery while I save up enough money and figure out an engine room modification to fix the problem correctly. I miss how well my boat started off the LFP primary bank. I did wire my setup with a full cross over so I can power all my house loads off the starter battery too.

Again, lots of considerations and details to work out.

Good luck.

Head Sail · Jun 21, 2020

Tim22 said:
If I keep an FLA for starting do I need to change the starter wiring to always use the FLA?

I would. Isn't that the point of a starting battery?

Head Sail · Jun 22, 2020

Tim22 said:
For me the only point of having the second battery bank is as a backup. This could be for starting the engine, but it might also be for running pumps, anchor windlass or whatever needs to be done when the main bank fails. I don’t really want to sacrifice this versatility if at all possible.

tim

Mainsail has wiring diagram I used.

https://marinehowto.com/wp-content/uploads/2020/03/1-2-BOTH-With-Dedicated-Start-Battery-Final-1024x864.png