[puddleglum]

Hi guys, I've been trying to think of an easy way to ease the load on my starting battery and still EOC with lights on. Presently, I'm not looking at an Alt. cut off switch, but that might follow If this works well. I've found some threads on this, but not quite what I'm thinking of. Most seem to end up with going to a deep cycle battery. I don't want to do that. It costs money (I'm cheap), adds weight and takes up valuable space.
I currently have two Lithium Ebike batteries that aren't getting used over the winter. The Ebike batteries (1-48v, 1- 24v) could be easily unplugged and brought in to charge. I have a couple of DC/DC converter options although neither are perfect. I'd like some input on which of them might be better and is there something I'm missing that would make this a bad idea.

First choice would be a 30 amp GE converter from a forklift. It is a robust, but large, unit that will convert either battery to 12.37 volts output. That won't keep the battery fully charged but shouldn't allow it to go dead either. Dealer says it is not field adjustable but they can rebuild it. It's sealed but I don't know if it's potted or if I could open it up and change something inside.

Second option would be a small 8-10 amp max. dc/dc that would only work with the 24 volt pack. I don't think that is enough to keep up with the loads from the lights, but has the advantage of an adjustable output and I can set the voltage wherever I want.

I'm thinking I would need diodes on either one to block charge current from the alternator, do you guys agree?