BB, you'll have to charge them one-at-a-time with a 12volt charger. Don't have to disconnect them either. You could charge them both together if you had a 24 volt charger the way you asked. You could charge them together if you connected the + to + & - to -. That will get you to 12 volts. The charger would have to be a strong one to charge them in a few hours, because if you had a 10 amp charger it would be like only having a 5 amp charger. Your BEST bet would be to add a on-board charger. They have some on the market under $200 that will charge all 3 batteries at once. With only a 10 amp charger it would prolly take 6 hours on each battery to bring it up to full charge after a hard day on the trolling motor. Hope this helps ya! <*)}}}><
You'll see the difference,,,on the end of your line! PROUD MEMBER OF TEAM GEEZER