Recharging battery via 7 pin cable

[JavaJelly]

I have a Brake Buddy which I really don't like but, am stuck with for now. Also, the famous customer support has not been there so far for me. I will give them another chance this week.

Anyway, I have a 7 pin - 6 pin cable from coach to car. However, I had read that 7 pin can recharge the battery in your car which is the biggest problem I have w/BB solution.

Is this true? If so, how is it wired?

[JavaJelly]

I have a Brake Buddy which I really don't like but, am stuck with for now. Also, the famous customer support has not been there so far for me. I will give them another chance this week.

Anyway, I have a 7 pin - 6 pin cable from coach to car. However, I had read that 7 pin can recharge the battery in your car which is the biggest problem I have w/BB solution.

Is this true? If so, how is it wired?

[Gary RVRoamer]

The 7th pin can be used for a variety of functions, but the most common is a "hot" feed to charge a battery or provide power to a brake unit like your brake buddy. You can simply connect it to the toad battery, but it really should have a diode so that current flows only in one direction and a fuse or circuit breaker. Make the wire large enough for at least 10 amps, but 15-20 would be better.

AT the coach end, choose either an always hot source (battery) or one that is hot only when the key is one. The latter is the safest but once in awhile it is handy to be able to keep charging the toad battery when the motorhome is turned off and on shore power.

[Pusherman]

Scott, I am pretty sure your 7-pin connector on your motorhome has 1 pin which is 12V hot. If you have a 12V tester, you can quickly determine if this is the case. In fact, my coach came with a wiring diagram which identifies the pins (they are standard in the industry).

Assuming this to be the case, consider a Toad Charge system which will continually charge the toad battery. It does not power the brake system, per se, but keeps the toad battery topped off.

[Hillbilly2]

I've installed a relay that is energized only when the MH is running, so the the toad will not discharge the MH battery. The diode will only prevent the MH from discharging the toad battery, as it will not charge the toad battery if it is set to block the current draw charging the battery. Everybody good and confused now?

[phays]

I considered doing the same but as yet have not. I contacted LSL and asked about using the extra hot wire as a source for charging my toad battery. They cautioned that you have to consider the total current carried by the ground wire. That wire must be large enough to carry all the current for all of the active lights on the toad plus the current used to charge the toad battery. You will need to check both the cable from coach to toad as well as the wiring on the ground wire from coach to its connector.