Originally Posted by jcc
Originally Posted by Wirenut
Hi All,
Any reason why I cant use a full size car battery to power the breakaway switch? Right now I have a full size battery on boar that is independent of the tow trucks electrical system. The battery just powers a radio and some lights on the trailer . The little breakaway system battery crapped out and I would like to eliminate it .
Thanks for looking

Only issue I see, is a small partly charged breakaway sized battery if seeing a system short for some reason, will likely drain itself rather quick, vs an unfused fully charged full size car battery might burn the trailer and its cargo down promptly. I don't know the current needed for brakes in a breakaway situation, but a large fuse, 30-50A? would give you some peace of mind I would think.


This is actually what I was wondering. Do they use the small battery so that the available current is very small as opposed to a larger battery. In the case of a short in the wiring between the battery and plunger switch the wiring is so short and small I sure it would simply burn off and it all outdoors.

When you apply your trailer brakes do they see a full 12 volts? Or would a full 12 volts damage the system? I think I should check that .

Thanks for all the replies.