Accidental polarity reversal on dual batteries hooked up to battery switch

Patrick_L

Seaman
Joined
Jun 22, 2016
Messages
58
Bummer ! I accidentally reversed polarities on 2 deep cycle batteries after taking them out for charging and reconnecting everything at dusk. They are both hooked up to 1/2/1+2/off battery switch on 94 boat. At first the switch had resistance when turning until... sparks flew.

Now my head unit along with the cabin power inverter dont work. I checked voltage on both batteries and wires going to the inverter: i get good viltage of 12.8V so there is power. Fuse on back of head unit (cd/radio) is not blown. Could it be the actual battery switch thats gone bad even though i tested it.. All lights, blower along with engine cranking work on all positions. Boat starts. Is it possible to fry head unit without damaging fuses or is likely it melted a wire and this is the reason for it to not turn on ?
 

dingbat

Supreme Mariner
Joined
Nov 20, 2001
Messages
15,417
Reversing the polarity on the input power to an electronic circuit is never a good thing...

If you got lucky there is a fuse on the power supply inside the head unit.
 

KD4UPL

Senior Chief Petty Officer
Joined
Feb 13, 2010
Messages
653
Likely your stereo and inverter are fried.
Your battery switch is fine since all that other stuff works, particularly being able to crank the engine.
 
Top