Put portable charger on backwards - Dumb and Dumber

[lesismore]

Too dumb to be working on mechanical stuff. Hot and tired and dead battery, I hooked up a portable charger to the battery to get 1990 4.3 OMC started, pulled boat out of water and charger was left on for a couple of hours until we got the boat home and noticed by stupidity. Battery then took a proper charge and seems to be OK, trim works, but everything else is dead. No blown fuses on fuse panel. Any suggestions what to look for?

 

[Boomyal]

Re: Put portable charger on backwards - Dumb and Dumber

If you hooked the charger up backward and the battery took the charge, welcome to Great Britain. You now have a battery that has a +positive ground. It ain't going to work anything on your -negative ground system. You probably also, at minimum cooked your alternator.

I did this once in a Chrysler MiniVan. Took out the ECU, the alternator and who knows what else. If there had been any charge at all in the battery, it would have thrown big time sparks when you tried to hook it up backwards but with the battery totally dead, it took the reverse connection with no sign.