Originally Posted by Barquito
If I start with both batteries topped-up, is it a problem to conntect two different size batteries to a charger in parallel? This is for winter storage.
Charge them both to full, independently, then stick them in your un-heated garage or shed etc.. By spring, in WI, they will still be damn near full. Cold weather, as in winter temps in the Northern US, DRASTICALLY slows self discharge and sulfation. If you want, or feel the need, top them up once or twice. No need to leave them connected and cooking away when not necessary. I've seen far to many charger failures that took out banks to even consider it for my own batteries.
Our boat sits next to the house and the batteries are still left on-board, purposely, all winter, with no charger or solar. If I work on the boat I may re-connect the bank and fire up the charger but that's it...