Battery Keeps Dying on Tow Car
First time we have experienced the tow car not starting. We frayed the electric connection cord (the one that runs from coach the towed car), since we did not know it was dragging on the ground. So t...
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Sounds like there's something that stays on in the Honda when towing, that is running the battery down. Very common, actually, and is the reason folks pull fuses, disconnect the battery, or run charge lines.
Constantly running a starting battery down like that will shorten its lifespan significantly, and really needs to be avoided one way or another. Starting batteries like are found in vehicles are not designed to be drawn down that low.
Put an ammeter across one of the main wires going to the battery, when the vehicle is basically in same mode as when you're towing it - key in ACC position if it has to be, everything turned off, tranny in neutral, all doors closed so no interior lights are on, etc. See what kind of amps are being drawn from the battery.
You're probably going to find there is something drawing it down. I found with our Ford Fusion hybrid, that even when I had everything turned off, there was still a 3 amp draw on the battery. This was making the battery weak even after just a 4 hour trip, so I had to do something.
Your choices to fix this are:
1. Find whats drawing it down and stop it, usually involves pulling a fuse (just one more thing to have to do when hitching and unhitching)
2. Disconnect the battery when towing (again, one more thing to do, and have to reset several things, ugh!)
3. Run a charge line from MH to towed vehicle, through the umbilical cord if possible (best choice if you can do it)
I opted for choice #3, and its worked great. MH already had a fused charge wire on the back, from the 7-way connector. Just wired that into one of the extra lines of the 6 way umbilical cord, wired it on the car side over to the battery with #10 gauge wire, and a 10 amp fuse. Also upgraded the ground wire coming from that umbilical cord connection to #10 gauge wire (on the towed vehicle).
Works great, you never have to worry about running down the towed vehicle's battery again. Towed vehicle's battery is fresh and fully charged when you get to your destination, no matter how long you've been towing. Even if you use one of the brake systems that can draw down the towed vehicle's battery, that is no longer a concern, either.
Constantly running a starting battery down like that will shorten its lifespan significantly, and really needs to be avoided one way or another. Starting batteries like are found in vehicles are not designed to be drawn down that low.
Put an ammeter across one of the main wires going to the battery, when the vehicle is basically in same mode as when you're towing it - key in ACC position if it has to be, everything turned off, tranny in neutral, all doors closed so no interior lights are on, etc. See what kind of amps are being drawn from the battery.
You're probably going to find there is something drawing it down. I found with our Ford Fusion hybrid, that even when I had everything turned off, there was still a 3 amp draw on the battery. This was making the battery weak even after just a 4 hour trip, so I had to do something.
Your choices to fix this are:
1. Find whats drawing it down and stop it, usually involves pulling a fuse (just one more thing to have to do when hitching and unhitching)
2. Disconnect the battery when towing (again, one more thing to do, and have to reset several things, ugh!)
3. Run a charge line from MH to towed vehicle, through the umbilical cord if possible (best choice if you can do it)
I opted for choice #3, and its worked great. MH already had a fused charge wire on the back, from the 7-way connector. Just wired that into one of the extra lines of the 6 way umbilical cord, wired it on the car side over to the battery with #10 gauge wire, and a 10 amp fuse. Also upgraded the ground wire coming from that umbilical cord connection to #10 gauge wire (on the towed vehicle).
Works great, you never have to worry about running down the towed vehicle's battery again. Towed vehicle's battery is fresh and fully charged when you get to your destination, no matter how long you've been towing. Even if you use one of the brake systems that can draw down the towed vehicle's battery, that is no longer a concern, either.
