Ok so our trolling motor was being worked on, and we borrowed a buddy's 55 lb trolling motor (never again.) I'm new to boat fishing. I know a full charged battery right off the charger will read 13ish and in like a day it will be down to around the normal 12.6. So we ran it from 6-12 and I tested the battery and it read 12.20 when we were finished. Battery was at 12.5 in the beginning of the day. When should I charge this battery and when is a battery considered dead, and needs a charge? Our other trolling motor is a 75 lb and requires both, so I will charge both to full charge before we use that again.

 

Thanks

When the battery is not being used, it should be fully charged as soon as possible, no matter what the use was.

I've got two small slow charger/tender's that I use from Harbor Freight.  When i'm not in the water, they're connected.