starting battery dead after 1 hour of turning off engine

1 year old starting battery dead after not using for an hour. battery load test results battery good. Alternator charges battery at 13.9 volts. Perform draw test and absoluteley nothing is drawing power while the battery selector switch is in the off position. i did run the cells low for a while and close to empty though there is no sign of rust on the plates. Cell levels are now on the full line as i added distiled water. Load test was done 3 times with battery fully charged. I am stuck any help? My problem understanding is all test result a good battery and alternator even after fully charged multimeter shows 12.6 volts even with battery switch off. Perhaps i damages the battery running the cells low, if so how does a load test result a good battery? An advice should imreplace the batery? The battery is being used with a volvo penta 225E engine on 1987 bayliner 2450....help please

Re: starting battery dead after 1 hour of turning off engine

Suspect a faulty load test.

Re: starting battery dead after 1 hour of turning off engine

Pretty hard to run cells low on a battery after one year. What were you charging it with? Whatever it was don't use it again.

Re: starting battery dead after 1 hour of turning off engine

Most of them old onboard chargers,we call them " buzz box's" overcharge the batteries,cook em right up. They can kill batteries in a year. I'd get a smart charger,problem solved!
Grub

Re: starting battery dead after 1 hour of turning off engine

Gotta believe there is a draw somewhere. Next time you charge the battery disconnect it from the boat and see if it stays charged.

Re: starting battery dead after 1 hour of turning off engine

Your bilge pump usually bypasses they battery selector switch.