Well, my onboard charger finally bit the dust. I need to charge the two trolling motor batteries. It appears that the series circuit is completed at the trolling motore plug (12/24/charge switch) rather than at the batteries. Can I charge each battery individually with a 12 volt charger or do I have to unhook everything first? I would guess I would move the switch to 12 but I don't know if that changes them to parallel. If it does change them to parallel, can I still charge each battery individually? I have no idea what charge is for. Probably to do exactly what I need to do. It is the boat in my signature below. Thanks.

My batteries are connected in series and I just put a new 2 bank charger on and ran each bank to each battery and just charge them as normal. I don't disconnect the series wire.

you can charge them one at a time, each is still 12 volts.

if your nervous about it just unhook one ground and break the circuit.

Thanks to both. I thought that was ok since my old onboard charger pushed 12 volts to each but I just wanted a second opinion.

If you have the charge/run switch on the bow panel (sounds like it from your post) and it is still connected to act as intended, you can place it on charge and charge both batteries while connecting the charger to one of the batteries. If the charge run switch is not operating, you can still connect a portable to one battery at a time and charge.

Thanks Jones. I thought that may be what that was for but I didn't want to mess it up. I will try that and see if it works.