Crossed battery cables - vhf fried?

Savent

Recruit
Joined
Oct 14, 2018
Messages
2
I installed a new battery and accidentally crossed the cables. Fortunately everything was switched off except the vhf radio. I saw quickly that the cables were wrong and corrected them, but of course the radio was dead. I checked and it had a fuse, which was blown. I replaced the fuse, but now when I turn on the power to the radio the fuse blows, even if the radio is off. Anybody know what’s up with this? I would think that the fuse wouldn’t blow with the radio off. Any help would be appreciated. Thanks -
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
Most DC electronics are made with components which are designed to flow current in only one way. Reversing the cables flows current in the opposite direction and shorts out other components. This damaged the radio beyond regular repair, so it needs to be replaced, there is no fixing it

One option for replacement is contact the manufacture and many have a standard repair cost which is cheaper then new.
 

Lou C

Supreme Mariner
Joined
Nov 10, 2002
Messages
11,798
One thing I do with a new to me battery is put a piece of duct tape near the positive post and put a big red + sign on it with the date the battery was installed. I think the pos post should be better marked.
 

poconojoe

Lieutenant Commander
Joined
Sep 10, 2010
Messages
1,966
Similar to what Lou C said, I use a paint stick to permanently write a "+" and "-" near the terminals. Any paint will do, I just happen to have paint sticks that I use to mark (ID) large electrical cables.
 

H20Rat

Vice Admiral
Joined
Mar 8, 2009
Messages
5,199
Fuses take time to heat up and melt, so at least for a couple milliseconds, the radio probably had about 900 amps running through some of the components. If you open it up, you will very likely find a couple parts that are now black carbon burn spots.
 
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