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Christyler avatar image

Charging Lithium Batteries from an alternator.

I am using 24v 200AH HE Lithium batteries, I want the option to charge from the truck alternator whilst driving, According to the Victron information you can just connect them to the trucks lead acid batteries via a Cyrix Li-ct. Is there a better option?

Lithium Battery
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BackYardSolar avatar image

The You Tube clip showing overheating Alternator when charging Lithium batteries is wrong and misleading. Your setup had a one to one ratio which is not the case in the real world as car alternators run at two or three times the engine speed and there is airflow as the car moves.

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Justin Cook - Bay Marine Supply USA avatar image

@Christyler, I'm not a huge fan of using the Cyrix to charge LFPs from your start battery except when budget and/or space is an extreme concern; as much as I do love the Cyrix line for being tiny, functional, simple, and relatively cheap, it doesn't give you the 3-stage charge profile that you really want to treat your LiFePO4 bank as well as you could. Personally I always recommend either the Sterling Alt-to-Batt Charger like the AB12120, which has an LFP profile setting, or the Sterling Batt-to-Batt Charger like a BB1260, also with an LFP profile setting.

Orrrrr you could wait two to three months (depending on your location) for the coming Victron Batt-to-Batt Charger.

I will say that the Cyrix definitely works, I just prefer a bit more customizability and intelligence when charging an extremely expensive auxiliary battery bank.

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Hi do you have any more info on this set up as looking at build a large Lithium banks and the Cyrix is part of the design so far , i was going to use the Victron Argo FET but advised to use the Cyrix set up thanks

@Stavarda, which info were you looking for? It's worth noting that, since my original reply, Victron has released the Orion-Tr Smart battery-to-battery chargers which resolve the issue nicely - you get the full advantage of an intelligent, programmable charge profile without the PITA of having to program Sterling B2B chargers.

Stavarda avatar image Stavarda Justin Cook - Bay Marine Supply USA ♦ ·

this is the possible set up form the alternator to charge the batteries will be a 24v set up.

cyrix.jpg (27.0 KiB)
Pat Davitt avatar image

It's me again. Alternator charging is somewhat out of my wheelhouse. I did, however, run into a very good research article on Lithium Batteries. It's a long article but has a section on alternator charging of lithium batteries. URL is below:

https://marinehowto.com/lifepo4-batteries-on-boats/

Should make for a good read.

Pat

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Thanks Pat, I was already thinking about the external regulated altinator, look like that's the best route to go.