
Battery Disconnect
#1
Posted 16 January 2004 - 01:51 PM
#2
Posted 16 January 2004 - 03:00 PM
As far as the battery in the trailer, I have never used any kind of disconnect switch in my campers, and more than once have had a dead battery because of someone leaving a light or something on.

#4
Posted 16 January 2004 - 04:28 PM
Here's where I put the (trailer) battery disconnect switch.
This was a 'spur of the moment' installation of two years ago, and I mean to do it right (one of these days).
Perhaps it'll give you an idea?!
#5
Posted 16 January 2004 - 05:01 PM
Fred Rosin
San Antonio
San Antonio, Texas
17' SD
#6
Posted 16 January 2004 - 05:16 PM
#7
Posted 16 January 2004 - 05:31 PM
Fred:Why do you need to disconnect it?
A 'silent culprit' is the water pump switch. As long as you have water pressure, the pump doesn't run. But if ya forget............
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Ya probably won't care until you've had a 'dead battery experience'. A disconnect switch is one of those things that doesn't cost much to install and the 'peace of mind' is worth it.
Casita, Scamp and other small trailers don't come with a battery disconnect switch, but the big RVs have em! Admittedly it's not such a big deal to recharge one small battery, but if you believe in Murphys Law, it'll come at the worst possible time.
#8
Posted 16 January 2004 - 06:51 PM
I am going to add one. Bob Hunt posted an easy wiring digram to follow, if you need help.
#9
Posted 17 January 2004 - 06:27 AM
Other hidden drains are inverters left plugged in. They draw a little current in stand by. Some people install car radios in their trailers. The clock and station preset memories draw current. Battery monitors (volt meters) can also draw current.
Don's solution is elegant if you can find where the 12v plus line from the Bargeman connector is located. Don can give us an idea where he tapped into his.
The marine industry already has battery isolators that disconnect the starting battery from the "house" battery when the starter battery falls below a certain voltage. It cuts out the starter (or car battery) while there's still enough current to start the engine. Here's my make a million dollar invention for Bargeman: The Deluxe Bargeman Connector with built in battery isolator. Youse guys are my witnesses. Just mail my check to the house!
Edited by Steve LaBroad, 17 January 2004 - 06:28 AM.
Steve LaBroad (CC#1262)
2003 16' Spirit Deluxe, "Castle Pretentious"
2018 Ford Flex AWD w/Ecoboost
#10
Posted 17 January 2004 - 07:22 AM
Steve:Here's my make a million dollar invention for Bargeman: The Deluxe Bargeman Connector with built in battery isolator.
All they would need to do is put a diode behind the terminal for the 'charge' wire. Allows current to pass one way buy not back 'upstream'. I don't know enough about 'lectric stuff' to know what size and such.
Already in the RV world is the set-up for towing your car behind a motorhome and wiring the 'toad's stop/tail/turn lights to work along with the motorhome lights. a diode kit is added to keep the toads battery and electronics isolated from the rest of the system.
#11
Posted 17 January 2004 - 07:33 AM
Steve:Don's solution is elegant if you can find where the 12v plus line from the Bargeman connector is located. Don can give us an idea where he tapped into his.
Look for the trailer charge wire at the car battery. There you should find an added wire on the + terminal. The charge wire should run directly from the battery to the brake controller.
Then check (with a continuity or volt meter) to see if it's the same as the 'charge wire terminal' at the bargman end.
#12
Posted 17 January 2004 - 02:17 PM

Based on a discussion about relays in another forum I ran a little experiment. I read the owner's manual for my 2003 Explorer with trailer tow package. It says it has a relay protecting the trailer battery charge line. That would be the plus source to the trailer. A relay is just sort of an electric switch. In theory, if the relay is tied into the switched circuit, there should be no current at the Bargman plug unless the ignition key's on.
I had an extra male plug to which I connected two wires (plus and ground) and I connected them to a voltmeter. I plugged in the plug and got zero volts. I turned on the ignition and immediately got +12v DC. Turning off the ignition sent the voltage to zero again.
That means, if I turn off the ignition on my tow, the trailer switches to internal battery. The reefer, for example, can't drain the tow's battery. No current is going through the Bargman. I guess you DO get a few extras with a tow package.
It also means that if I plug the trailer into a generator (or solar panel) while plugged into the tow vehicle, the generator's current is stopped at the relay and won't send current "backwards" into the tow past the relay if the tow's ignition is off.
Cool!
By the way, referencing a discussion we've had about battery switches, the relay is protected by a 40amp fuse.
Steve LaBroad (CC#1262)
2003 16' Spirit Deluxe, "Castle Pretentious"
2018 Ford Flex AWD w/Ecoboost