question

adriano avatar image
adriano asked

Switching from Sead Lead Acid batteries to LifePO4

In a little sailing boat I'm thinking to switch from SLA service batteries 330Ah (n. 3 x 110Ah) to LifePo4 batteries.

Assume that 330 Ah was the correct services sizing, I have n. 3 question :

1) was my Atlas Combi 12/1500 (50 Ah nominal charge) able to charge the LifePo4 or I must change something in it (the charge curve) ?

2) what was the right LifePo4 size to remain a little bigger (more confortable) ?

3) the engine alternator was sized to 60Ah because I don't want to overcharge my SLA batteries (more time was more endurance ...). With LifePo4 that accept bigger charge, need I to change alternator with an High Output Alternator (perhaps 120 Ah) ?


Thanks to all,

Adriano

battery chargingLithium Battery
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3 Answers
wkirby avatar image
wkirby answered ·
1) I don't think the charge curve of the Atlas Combi can be (easily) adjusted to suit LifeP04.

2) 200Ah LifeP04 will give you a bit more usable capacity than 330Ah SLA usable capacity.
3) I presume you mean 60A alternator - this should still be fine, you can keep it unless you want to charge faster.

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adriano avatar image
adriano answered ·

Thanks for your response WKirby.

Another thing. For SLA or AGM I don't have dubt : N. 3 different batteries was better than n. 1 bigger (as we must also think about the weight).

But for Lifepo4 ... so little heavy, and having (everyone) the BMS module inside batteries ... is better :

- n. 1 unique (bigger) 200 Ah lifepo4 ?!?

- or n. 2 x 100 Ah lifepo4 (same 200 Ah capacity) ?!?


Final conclusion.

And so, if you want to switch from SLA to Lithium, (as I already feared), you must think also to change the Charger (my old but good Atlas Combi 12/1500).

What is actually the Inverter / Charger so good for newer battery types LifePo4 ?!?


Thanks,

Adriano

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wkirby avatar image
wkirby answered ·

First of all, I forgot to mention in my previous answers, if you are thinking seriously about Lithium batteries then for alternator charging you need a regulator for those type of batteries. You cannot charge directly from the alternator like lead acid batteries.

1x 200Ah or 2x 100Ah, it is better to have 1x battery to think about, but 2 will not be a problem really. Same capacity.

It's a shame about the Atlas Combi, it is a good one. MultiPlus will be a good replacement. 12/1200 or if that is too small then 12/2000.

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