7 pin trailer wiring / battery charging questions

[SnowRidge]

Hey Hazmat, are you aware that pulling the safety rip cord (lanyard) while the trailer is electrically hooked to the tow vehicle can destroy the brake controller, by backfeeding the controller from the breakaway battery. It's a lousy system. It sucks, but that is what can happen with at least some, if not all of the controllers. The literature that came with my controller specifically warned of this.

To test the breakaway system, always disconnect the trailer connector from the tow vehicle first. Always reinsert the lanyard thingy in the breakaway box before reconnecting the trailer connector to the tow vehicle.

Not sure if you knew this or not. Thought I'd mention it just in case.

SnowRidge

 

[Phred]

On any vehicle with a 12V system you should have about 12V with out the engine on, ie.. no alternator running.
Engine running you should have ~14.4V to charge the 12V battery.

You may have a diode in the trailer circuit to keep it from feeding power back into the tow vehicle. Sometimes these burn up if marginally sized....
But it should be failry clear. Do you get the 14.4V with the engine running at the tow vehicle jack? if so work your way down the trailer wiring.

Fred

 

[hazmat]

<font color="blue">Do you get the 14.4V with the engine running at the tow vehicle jack? if so work your way down the trailer wiring. </font>

Nope - I get 0 volts there. I'm guessing that the RV shop that installed the brake controller & 7 pin plug didn't wire it in. Someday I'll take care of that (A bit busy now)

My immediate "problem" is that the battery voltage on the trailer is low & I don't have a charger (yet /forums/images/graemlins/tongue.gif). I'll charge it on Dad's in Maine.