Hooking up boler battery to Tug battery

[Andy H]

Hi Folks,
My boler came without a battery .
I just installed a battery holder and box on the trailer tongue and was wondering whether I could simply run a + and - wire from my Tug battery to my trailer battery and have the tug charge the boler battery while towing.
I'm not an electrician and alot of this stuff I've seen here just doesn't sink in.
I have the usual flat 5 pin plug and was thinking of using a seperate2 pin(if I can find one) for this charging hook up.
Will it work ?
Any suggestions ?

Thanks Folks,
Andy H

[Brian B-P]

You can use a separate power plug, but for ease of switching between trailers and tow vehicles, and for availability of parts, it makes sense to use standard connectors. The 7-way connector (6 flat blades around a round centre pin) known as the "RV" or "Bargman" type is essentially the standard, and includes pins to connect the battery power, as well as electric brakes (just don't use the ones you don't need).

The flat 5-pin (presumably the one with 5 round pins in a row) connector is not really very common now. The two-pin version of the same thing is readily available, but those connectors don't have very large contacts or wires, so they're not good for much current - better suited to lights than battery power supply.

There are quite a few discussions here in the forum of battery connection details, once you've picked a connector; I suggest a search for "isolator" or "solenoid" to find the appropriate topics. Also, there are some diagrams and other information the Resources section (menu on the left side of the page).

[Gerry]

Andy,
Here is what I did and it works just fine.
I ran a #8 wire off the Pos. Post of the battery, into a 30Amp breaker (purchased from automotive store) then continued, all the way back to an open, unused pin of my 7 pin connector.
Then from the matching pin on the camper I installed another BLK wire into the group and took this into the battery box as the charging wire for the camper battery.
The ground for this system is already in the harness as a White (on Boler) so I also bugged into this to get the camper battery grounded to camper frame.
The solenoid Brian is talking about will insure that while your engine is turned off there will be no danger of running down your car battery but I just make sure if I am not on the road, for an extended time, that I just unplug the the connectors.
I have had this system for a year now and both tug and camper batteries are always fully charged after driving home from a weekend of boondocking
Gerry the canoebuilder

[Pete Dumbleton]

Be sure that you have a fuse or circuit breaker on the wire at the egg battery so if there is a short (like at the open connector) the wire won't burn up (It is considered unsanitary to have burning wires near the LP tank).

Also, be sure that the white wire on the tow vehicle end of the connector is securely grounded to the frame to ensure an adequate return path for when the trailer lights are on, the brakes are on, perhaps the reefer is on and the battery is charging. What I do is when I run my charge and brake wires, I also run a wire to the negative battery terminal on the TV *and* also ground it to the frame.