Charging 12V LiFePO4 battery from outboard and car

[adamjs16]

I brought a couple of 12V 30Ah LiFePO4 (link)

I want to be able to charge them using the alternator of my car and my outboard. My outboard is manual start and I havbe fitted a reg-rec but I beleive this would still alllow voltages that are too high for the batteries.

I brought a buck converter but in retrospect I don't think this will be safe as it does not limit the current supplied by the batteries.

Does anyone have any suggestions on how to accomplish this?

[Pikey Dave]

Originally Posted by adamjs16

I brought a couple of 12V 30Ah LiFePO4 (link)



I want to be able to charge them using the alternator of my car and my outboard. My outboard is manual start and I havbe fitted a reg-rec but I beleive this would still alllow voltages that are too high for the batteries.



I brought a buck converter but in retrospect I don't think this will be safe as it does not limit the current supplied by the batteries.



Does anyone have any suggestions on how to accomplish this?

The current supplied by the batteries is determined by the load, not the charging circuit. Are you sure you’ve got it the right way round?

[adamjs16]

My bad. I meant the current supplied to the battery by the charging circuit.

[Pikey Dave]

Originally Posted by adamjs16

My bad. I meant the current supplied to the battery by the charging circuit.

In that case, have a look at my Volaire build thread. I’m using a Buck regulator to charge a 20ah lithium battery. The regulator can control both output voltage & current. I have it set to 12.6V /2A. It’s been going for a couple of years now, no problems. It came from Amazon around £15 iirc.