LiFePO + MPPT solar + what else?

[SY Kelpie]

Been researching LiFePO and quite surprised to see how much prices have fallen.
I'm thinking of getting around 500w of solar, run through a MPPT charge controller that is compatible with lithium cells, and using a bank of 12v LiFePO batteries wired in parallel.

The question is- what else will I need in order to complete my setup?

[CatNewBee]

Originally Posted by SY Kelpie

Been researching LiFePO and quite surprised to see how much prices have fallen.
I'm thinking of getting around 500w of solar, run through a MPPT charge controller that is compatible with lithium cells, and using a bank of 12v LiFePO batteries wired in parallel.

The question is- what else will I need in order to complete my setup?

Hi,

I would say general understanding of the parameter settings, your electric system and your other charge sources. You may need a b2b charger to control your alternator power and voltage and also reconfigure your shore power charger.

[Adelie]

I would go with several small MPPT controllers as a way to deal with shading rather than 1 big controller for all the panels.

[SY Kelpie]

Thanks. So it should all come down to how the new LiFePO battery bank interacts with the other systems (alternator, shore power, engine start battery)?

I'm asking the question because when I price up the batteries, MPPT controller, and panels, it comes to cost that seems almost affordable. But when I look at the price of a ready to go system it is hugely more expensive and includes things like BMS that I don't fully understand. Obviously people spend their money on this kit for a reason so I need to do more research on what the extra money is getting me.

FWIW, in ten years of boat ownership I have never once actually plugged in to shore power. Generally we are off-grid when cruising, and make do with solar and engine charging. Our new boat also has a wind gen, just to complicate matters!

My initial thoughts are to keep a bank of lead-acid batteries charged by the existing sources (engine, wind, small solar panel) and build a totally separate second bank for purely domestic use, charged by the new panels. However I expect that I would need to have a way of charging this bank from the engine and/or directly from the lead-acid bank.