Charging trolling motor batteries

[Shorelunch]

Question for the experts. I'm setting up a 24v system in a boat with little storage (bench seats and one console - Crestliner Canadian). I'm running the main red wire from the Terrova to battery 1's positive terminal, the black main wire to battery 2's negative terminal and jumping battery 1's negative terminal to battery 2's positive terminal.

I have a 2-bank onboard charger from a previous boat, but there's really no place to put it in this boat. Could I use a normal battery charger - and could I hook the positive cable to battery 1's positive terminal and the other cable to battery 2's negative terminal, or would I need to charge them separately? I would think they would get an equal charge with the jumper joining the batteries?

Or should I just use the 2-bank charger like a normal charger and connect and disconnect after each use?

[Schloogs]

Thats an interesting question. I don't think if will charge by hooking to positive on one and negative on the other. I may be wrong (happens all the time) but I would recommend the onboard charger and charge both batteries at the same time.

[marine_man]

When connected in series you can NOT connect a charger to the positive on one and the negative on the other unless you're running a 24 volt charger.

Regardless of what style charger you use, you'll need to connect the positive from the charger to the postive post on one battery and the negative from the charger to the negative post on the same battery.

Is there a location in the boat you can mount the on-board charger? You can extend the wires on the chargers, your charging performance will suffer, but not significantly.

marine_man

[Shorelunch]

12 volt charger, so I'd need to charge separately, correct? Thanks for helping me not blow things up! I would imagine that charging the two (new) batteries separately is not and ideal situation?

There's a console on the boat and the on-board charger could probably go underneath. However it's not my boat and I'm trying not to get things too complicated. I suppose I could remove the charger from the boat at the end of the year. Has anyone used an on-board charger as a portable - hooking it up to both batteries and then removing when done?

Thanks again.

[marine_man]

Yes, you'd need to charge each battery separately... you won't have to disconnect anything, but it won't feed between the two.

One option here is to make another jumper, and when you want to charge both batteries with one charger, disconnect the postitve to negative jumper, connect it positive to positive and add the other jumper to go negative to negative. You've now connected them in parallel and are at 12 volts, and can charge both batteries with one charger.

The advantadge of the double bank charger though is it'll charge faster since you've got two seperate banks, likely with more amps than the one charger if you connect the batteries in parallel, like described above.

Using an onboard charger as a portable charger works just fine. They don't have to be permanently mounted by any means. If you really want to get fancy you could purchase some disconnects and connect them to some wires you have attached to the battery, and put the opposite disconnect on the charger and connecting / disconnecting would go pretty quick. For that matter, you could put alligator clips on the ends of your onboard charger leads and accomplish the same thing.

marine_man