howlong 4 residual battery drain 2 drain a battery

[edwardh1]

mid size car battery in a outboard boat, has memory presets, radio company sez 8 ma drain, even when radio is off how long to drain the battery?

 

[eljefino]

A car battery is about 80 amp-hours. 416 days. Normal chemical reaction will kill the battery faster than this load.

 

[Colt45ws]

Yeah, the self discharge rate will get it before that does. They is why a battery tender of some sort is a good idea even on a battery that is just sitting.

 

[2cool]

You won't get 416 days because the memory presets may be lost once the battery drops below 9.5 volts. That's the limit for most cars, and your electronics probably aren't different as far as operation, just the packaging to resist a marine environment. I vote also +1 on the battery tender. Remember, a starting battery for a car is designed to give big amperage for a short period; not a steady drain for a long time.