Checked on my boat yesterday and found two totally dead batteries. (left cabin lights on) MY question is how long can I leave the shore power batt chgr on.
The built in charger is 30a, will this fry the batteries if left on too long even if I leave the switch in the "both" position?

Thanks,

Kurt

You should be able to leave the charger on for as long as you want. I usually plug mine in once a month for a week while in storage. A friend of mine keeps his plugged in all winter.(battery swithes on off)

Shore power should not fry your battery charger. We leave ours plugged in every week....never had a problem.

I plug mine in once a month for a few days-----keep the switches OFF. Never a problem.

Mine is always plugged in,switches off.

I've often wondered the same thing, Kurt. My charger in my Formula was a 30A output and if you leave 12v batteries continuously charging at 30A it will boil them dry and cook them. The only thing I can think is if the others who responded have the newer "smart chargers" that reduce the charge rate as the battery voltage comes up and then apply only a "float" charge rate to keep the batteries hot. I never left mine on for more than 24 - 48 hours at a time.

My Tiger is an '02, which the dealer had for a year. I bought the boat new in 01/03, and found out that the dealer had plugged the shore power all the time. When the boat was delivered to me in March/03, one battery was completely dry and dead, and the other was almost dry, barely holding a charge.

The charger is an automatic one which is not supposed to cook the batteries. In contrast to all whom have posted here, my only oppinon (with cooked batts), the boat was plugged into shore power TOO much. The batteries were un-recoverable.

This may be an isolated case, possibly, battery neglect on the dealer's part. I purchased new AGM glass mat batts from Westmarine and have not had a problem since. I do plug into shore power, but I turn the battery charger off from the panel inside the boat. Only if a battery is showing lower than 12V, will I turn the charger on, and then, only for 2-3 days, max.

I dont believe in Lifetime batterys,they have a finite life anyhow, just my .02. you should be able to leave them on charge,turn on the switch on the panel, turn the battery switches off, and let it charge, mt tiger is a 00. I had the same thing when the stereo guy left them on.

Speaking of lifetime batteries, when I use to boat in the ocean, I always put two new batteries in every year. Cheap insurance, if you boat in certain coditions and places.