A common issue with towed vehicles is the ignition must often be placed into the ACC position while it is being towed, which can drain the battery. While GM recommends removing 3 fuses from the Grand Am while towing, battery drain can still occur by the use of a portable brake system in the towed vehicle, which also uses the vehicle's battery.

Solutions to this problem is to either start the car every 4 hours or so, use a portable "starting battery" to run the brakes, or to charge the towed vehicle from the motorhome. The first two solutions can result in loss of brakes in the towed vehicle should the battery be completely discharged, so the third option is the only real solution for long distance towing.

There are several towed vehicle chargers on the market that I am aware of, including:

• RVI (RVIBrake) Towed Battery Charger.
• Brake Buddy Towed Vehicle Battery Maintainer.
• LSL Products Toad Charge.

I decided on the RVI Towed Battery Charger. It was the middle priced unit of the three ($50), and well built - the box is cast aluminum. Electrical esign-wise, I can't say which unit is more sophisticated or better, so I am going on what I do see. One thing I did not like about the LSL Toad Charge was it's use of a 2 part system - one of which needing to attach to the motorhome's battery. It just seemed more work to install it.

Installation is pretty easy, however you have to find a suitable location to mount the box within 5ft or so (as that is the length of cable that is supplied). RVI suggests cable-tying the box to other wiring, but for me - that is just too much of a "Rube Goldberg" approach (or I suppose these days, it would be a Red Green approach).

After finding a suitable solution, it was a simple matter of running the battery wires over to the battery and finding a path for the wire that attaches to the motorhome. I am using a 6 wire connector for the trailer lights circuit, and the center pin is a 12V source - designed for this kind of purpose. You will however, need to check your motorhome for a 6-pin connector - or wire one it needed.

If you have to reconfigure your motorhome for a 6-pin connector, be sure you use heavy wire for the 12V and Ground connections. I suggest 12AWG, but you will also need to ensure the wire is fused at the source (battery, fuse block, etc). While 12AWG may seem overkill at first, realize that with DC wiring, there is a resistance issue with long wires. Simply put, the longer the wire, the more voltage is lost. If too much voltage is lost along the wire, the battery charger will not have enough voltage to operate. The easiest remedy for this is to increase the size of the wire from the motorhome to the towed vehicle.

For all of the wiring, we used plastic split loom, wrapped with electrical tape to secure and protect everything. Wiring was secured to the vehicle with cable ties.

Unfortunately; at least for this installation, my vehicle - being a GM vehicle, has a side-post battery, so some modification is in order to connect the battery to the charger. To accomplish this, I found some adapter bolts that are specifically designed to connect circuits to a side-post battery. You can find these at most auto stores.

Suprisingly, I had some difficulty in getting these adapters to fit. The rubber boots for both positive and negative terminals were designed as such that they held the existing terminal bolts captive. So I had to cut around the top of the boots so the terminal bolts could be removed.

Another issue I had was the existing terminals were too small for the new terminal bolts. This was OK, as I was wanting to replace them anyway.

As you can see from the photo, the only means to identify the terminal function (Battery + or Battery -) is by the color code of the terminals. The manufacturer simply marked the yellow terminal with a black line to indicate the negative terminal.

This is not acceptable in my view, and when I replace the terminals, I'll add a 6" long piece of red heat shrink to clearly identify the Battery + wire.

Installation of the battery charger to the battery is simple with the proper adapters. It makes for a fairly neat installation. I was also able to re-configure the positive terminal cap to protect the positive lead.

It should go without saying that when using such post adapters, that you need sufficient clearance around the battery so that the longer terminals do not inadvertantly touch something they should not. As well, make sure your battery is fully secured so it is not bouncing aorund. These things are just common sense.

References:

RVI Towed Battery Charger
Brake Buddy Towed Vehicle Battery Maintainer
LSL Toad Charge