Dead toad - windshield wipers?

[Diesel Pusher]

No device necessary, unless the hot wire is meant to provide power for additional things. On my coach, pin 7 was already live. All I did was get a 7 pin (round) cable to fit the coach to 5 wire flat adapter (6 wire round also works). Four are used for lights and the 5th goes directly to the positive terminal (with in-line fuse) on the battery.

 

[Kevin D Pem]

No device necessary, unless the hot wire is meant to provide power for additional things. On my coach, pin 7 was already live. All I did was get a 7 pin (round) cable to fit the coach to 5 wire flat adapter (6 wire round also works). Four are used for lights and the 5th goes directly to the positive terminal (with in-line fuse) on the battery.

So follow the flow!!! What I mean is, what is the voltage on pin 7 when acc is on! Is the voltage still at charge maintenance voltage 13.6 even when the brake lights come on? Depending on length of and size of wire, this may not be so! If the battery voltage is higher than pin 7, the power will come from the battery! Basically the maintainer is a boost converter that will supply 13.6 volts, no matter what the voltage dips to on pin 7.

It will likely work without, but you may still have a depleted charge. That being the case, why not just put in a maintainer???

 

[Diesel Pusher]

Voltage on pin 7 is only live when engine running (turning key to ACC does nothing). Pin 7 is intended to provide 12v for (general purpose) towing applications.

 

[Joe Hogan]

No device necessary, unless the hot wire is meant to provide power for additional things. On my coach, pin 7 was already live. All I did was get a 7 pin (round) cable to fit the coach to 5 wire flat adapter (6 wire round also works). Four are used for lights and the 5th goes directly to the positive terminal (with in-line fuse) on the battery.

First thing to check is the 7 pin connector, Pin ?? for 12v power (maybe pin 7 or some other pin depending on how coach is wired or not). Then determine if there is 12v power, When said power pin is powered, key on, always, etc. This is to avoid chasing your tail when configuration is wrong ( do not ask how I know this) .
Once you have determined your source, just follow the wires on your vehicle connector to determine which wire has the constant 12v to the positive and ground lead to a 12v battery charger. Then attach the wires of the 12v battery charger to the battery.
Smarter electricians feel free to correct me...

And to not disappoint Towed Battery Charger Plus for flat towing

 

[Joe Hogan]

And just in case there is a question on standard 7 pin wiring

Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think) | etrailer.com

A 7-way plug connects your trailer and tow vehicle and provides the required lights, turn signals, brake power, battery hot lead, reverse lights, and ground. Most of us aren't electricians, but that doesn't mean wiring a trailer or replacing corroded wiring is beyond us. We'll walk you through...

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