Charging Trailer Battery?

[Marcus Miller]

All, I just purchased a new 14 foot tandem axle trailer, with electric brakes on a singel axle. We are running a brake controller in the truck, and the guys at the local trailer shop said that due to running the brakes, we would need to watch our voltage for the onboard battery. Any thoughts on that?

Marcus

[joeg]

Marcus--Checking around a Pick-up truck forum I came upon a post about low voltage affecting trailer braking--quite logical.

The point of that post was to make certain the wiring to the trailer was in tip top condition and good size wires (min. 12 Gauge)used to prevent voltage drop. The guy measured things before and after and was impressed.

Grounds are as important as power leads too!

Cheers

[Greg Amy]

I think you guys are talking about two different things...

Marcus, you're talking about the breakaway battery, correct? You should ahve that battery wired into the charging system of your truck. That way while you're under way the breakaway box is being charged. If your truck is not wired for it, then put your breakaway on a battery tender occasionally to make sure it stays up to snuff. Out in the middle of Kansas at 2:00 AM is not where you'll want to test the breakway battery voltage; you'll never find your trailer until the next morning...

Joeg, you're talking about voltage to the trailer brakes, correct? Since most electrical trailer brakes are actuated by varying voltage, it is important to have good connections from the truck to the brakes, and back to ground. In fact, I know of some folks that rely on the hitch to provide ground back to the truck; bad move. Run a ground through your wiring harness back to the tow vehicle. Problems with bad connections on trailer brake wiring will manifest itself as inconsistent braking levels and possibly occasional lack of trailer brakes.

Capiche?

[joeg]

Greg--Correct!

[Marcus Miller]

Greg, you got it.

I'll have to look at the wiring on the trailer. I'll admit to not knowing how the thing is wired, other than the lights worked when I towed it off the lot , that's as far as I got...
edit: spelling....
thanks!
Marcus


[This message has been edited by Marcus Miller (edited May 19, 2004).]

[Eagle7]

Originally posted by grega:
Marcus, you're talking about the breakaway battery, correct? You should ahve that battery wired into the charging system of your truck.

What's the right way to do that? Just connect a hot wire to the breakaway battery?

------------------
Marty Doane
ITS RX-7 #13
CenDiv WMR

[Greg Amy]

Check the wiring diagram of your breakaway system, but basically that is correct. You want the charging voltage to the battery on the hot side of the switch (you don't want 14V to the wrong side, it'll activate the brakes.)

[Rex B]

For the breakaway battery, you might consider a small solar battery charger. I keep a battery in my trailer to run a winch. A $10 solar charger from Harbor Freight keeps it hot between outings. Should be fine for the smaller battery, as the output of the chargers is only 1.5 amps on a hot day.