#TRAILER BREAKAWAY BATTERY CHARGING INSTALL#

The braking controller is actually quite sopisticated, and bases the PWM to the trailer brakes on the rate of de-acceleration of the towing vehicle (using a MEMS accelerometer).

During normal towing, the brake controller in the towing vehicle modulates the braking by varying the Pulse Width of the braking current. Note that supplying these type of electric wheel brakes with a steady 12V will lock up the wheel so that they skid. As the clothes-pin is pulled out of the breakaway switch body by the cable presumably still attached to the towing vehicle, that is supposed to lock the brakes on the trailer to stop it.Īt that moment, the source of the 12V required to apply the brakes (about 2A per wheel) must come from the trailer-mounted 12V 5Ah SLA battery. If the trailer were to become uncoupled from the towing vehicle at speed, and the safety chains are not able to keep the trailer hooked to the towing vehicle, then the electrical connection would be severed (leaving nothing to power the electric brakes if there is no battery in the trailer). The other end of the steel cable is clipped to the rear-bumper of the towing vehicle, independant of the normal trailer coupling, the safety chains, or the electrical connection between the trailer and the towing vehicle.

The clothes-pin is attached to a small-diameter (0.1') steel cable. To rearm the switch, you have to push the clothes-pin back into the body of the switch. If the clothes-pin is pulled out of the switch body (takes a bit of force), the contacts close, immediately locking the trailer brakes. It is held open by a thing that looks like a plastic clothes-pin. Includes battery box with 3 mounting options, 5 Amp battery with push to test LED test meter. The industry does it this way: The breakaway switch is mounted on the tongue of the trailer. Breakaway system for 1 to 3 axle trailers with electric brakes. The capacitor is so the Schottky doesn't get zapped due to transients. This should float the breakaway battery at ~14.2V - the forward drop of the Schottky diode, or about 13.7V The 2Ω will prevent from blowing the fuse in the towing vehicle (and limit the initial charging current to the SLA) if the battery gets seriously depleted. I added three components into the trailer breakaway battery box as shown below. That is consistent with all of the trailer running lights being on when the towing vehicle is connected to the trailer with engine running. This product is easy to hook up and fairly inexpensive compared to the price of a new battery. I did notice that, by default, every time the towing vehicle is started, the tail/running lights (brown wire) pin 3 has about 14.2V on it with the engine running. Part PTW2997 works great for charging your breakaway battery when the trailer is not in use. I next checked the 7 pin connector on the towing vehicle, only to discover that pin 4 is apparently not hooked up in the vehicle, either. No current is ever drawn from the battery unless the breakaway switch closes, but how did they expect a lead-acid battery not to self-discharge after a year or two? That is normally used to charge the breakaway battery in the trailer, but the black wire in the trailer harness was missing, so the trailer manufacturer didn't provide a means of charging the battery. In looking at the standard 7-pin trailer connector, I noticed that pin 4 is supposed to have 12V supplied by the towing vehicle. Breakaway systems are designed to apply the brakes in the event that the trailer becomes disconnected from the tow vehicles hitch while in motion. For what it is worth Victron also have a lot of info online, as I imagine other manufacturers would too.I was working on a several-year old car-hauler double-axle flat-trailer (replacing one of the electric brake actuators) when I tested the breakaway battery/switch only to discover that the 12V 5Ah SLA battery was stone dead. Victron make a range of pretty sophisticated charge controllers and other solar related equipment, it is mostly expensive, but pretty highly regarded in RV and Marine circles, and there are also other less expensive brands, some of which also seem to work well. KrynWith the small solar panel I think that you would need a solar charge controller to control the charging otherwise you are likely to kill the battery by overcharging it and boiling it dry. My Brother has one connected to each of his Harley and Kawasaki 900, to keep them topped up.

#TRAILER BREAKAWAY BATTERY CHARGING INSTALL#

Hi Steve, I'd be inclined to install a small 10watt solar panel to say a tool box, or somewhere there will be constant light getting to it, when you get around to installing the winch, connect it to both batteries to top them both up.įailing that install a Projecta charge n maintain, that will keep the battery charged all the time.

Trailer breakaway battery charging