Vibe 287QBS kills battery

[RvCamper5]

Hello...
A few years ago bumper towing our camper and made a tight turn and some of the towing wire harness was pinched/gouged. We stripped back damage wires and use wire nuts to reattach any connections then wrapped in plastic bags(to keep dry) then taped the entire thing up HEAVILY!
NEVER any troubles the past couple years when out of blue I parked tow vehicle and camper at a rest area with all lights off and within minutes it had killed my battery! Had another experience the next month with a different tow vehicle and it kill that battery as well! Any ideas here? Is it simply one of the repaired wires has a short?
Any insights?

[Hclarkx]

It seems unlikely to be a short. One would expect a short to draw enough current to blow a fuse in the tow vehicle before the battery is discharged much. If the fuse has been replaced with a too large one, it might not blow and instead the wire to the short could get hot and melt its insulation. This is assuming the battery is healthy and can supply considerable current. Since it seems neither of those is the case you could hook up and look for some appliance or light that has been left on. If that doesn't pan out, use a current meter and look for current that is being drawn. Wiggle wires here in hopes of triggering whatever is causing the intermittent short or load that is running the batteries down.

It's possible that the battery is being drawn down while you are traveling and not just while at a rest stop or similar. This could explain how a few minutes in a rest stop with some modest parasitic load could result in a run down battery. Though one would expect the alternator to keep the battery charged. Alternators can fail of course, but here we have two different tow vehicles similarly affected and that points to a problem in the trailer. I.e., a stuck brake light or running light or electric brake or similar.

A device like this can be very helpful when trouble shooting a 12 volt DC system. https://smile.amazon.com/gp/product/...?ie=UTF8&psc=1

[doanshop]

How old is your battery? Is it still good?

[Vibe101]

Does your trailer have DC powered (electric) tank heaters?

Does it have a DC powered fridge?

Both?!?!?

Those electric heater coils use a bunch of power and would kill the battery in a hurry.

Sounds like a lead acid single battery? If so it sounds like it is due for a replacement.

[sdelam]

Just to clarify, you are saying your Tow Vehicle Battery is being drained/killed by your trailer. But you are not having any issues with your trailer battery?

[Vibe101]

Sounds like some high draw DC items is being left on in the trailer (inverter/ tank heaters/ furnace/ power charger for devices)

A break in the trailer wire harness that creates a short would burn out the respective fuse in the tow vehicle so I bet the cable repair is still good.

Most stock wired tow vehicles have a "PIN 4" in the "GM 7 PIN" plug this PIN 4 is the one that supplies power to the trailer from the tow vehicle when the engine is running. When the tow vehicle engine is stopped electricity will flow either way depending on the loads of the different ends. If you leave the headlights on the tow vehicle then electricity will flow from the trailer to the tow vehicle until both batteries are dead.

If the trailer battery is bad and will no longer hold a charge then when the engine is stopped the electricity will flow from the tow vehicle back to the trailer until both batteries are dead.

In either of the above case you know that the fuse in the tow vehicle that protects the wires to PIN 4 is good because power is flowing back and forth.

If you have a digital volt meter do the following:

1-With trailer disconnected measure volts in trailer battery (should be 12.3+ volts)
2-With engine off measure volts in tow vehicle battery (should be different but still more than 12.3 volts)
3-Connect trailer connector plug and measure volts in both batteries (should be close to the same)
4-Start tow vehicle with the trailer connector still connected and measure the volts in both batteries (tow vehicle battery should be 14+ volts and trailer battery should be slightly less but still way more than you measured in step 1)
5-Disconnect trailer plug and turn on some high draw DC stuff in the trailer (vent fan and/or furnace) and measure the trailer battery voltage and it should be slightly less than step 1 but decreasing very slowly like it will take more than 10 hours to reduce volts from 12.3 volts to less than 11.8 volts

[CaptnJohn]

Originally Posted by Vibe101

Sounds like some high draw DC items is being left on in the trailer (inverter/ tank heaters/ furnace/ power charger for devices)

A break in the trailer wire harness that creates a short would burn out the respective fuse in the tow vehicle so I bet the cable repair is still good.

Most stock wired tow vehicles have a "PIN 4" in the "GM 7 PIN" plug this PIN 4 is the one that supplies power to the trailer from the tow vehicle when the engine is running. When the tow vehicle engine is stopped electricity will flow either way depending on the loads of the different ends. If you leave the headlights on the tow vehicle then electricity will flow from the trailer to the tow vehicle until both batteries are dead.

If the trailer battery is bad and will no longer hold a charge then when the engine is stopped the electricity will flow from the tow vehicle back to the trailer until both batteries are dead.

In either of the above case you know that the fuse in the tow vehicle that protects the wires to PIN 4 is good because power is flowing back and forth.

If you have a digital volt meter do the following:

1-With trailer disconnected measure volts in trailer battery (should be 12.3+ volts)
2-With engine off measure volts in tow vehicle battery (should be different but still more than 12.3 volts)
3-Connect trailer connector plug and measure volts in both batteries (should be close to the same)
4-Start tow vehicle with the trailer connector still connected and measure the volts in both batteries (tow vehicle battery should be 14+ volts and trailer battery should be slightly less but still way more than you measured in step 1)
5-Disconnect trailer plug and turn on some high draw DC stuff in the trailer (vent fan and/or furnace) and measure the trailer battery voltage and it should be slightly less than step 1 but decreasing very slowly like it will take more than 10 hours to reduce volts from 12.3 volts to less than 11.8 volts

Not sure about Dodge but there is no back flow with engine off on Ford products

[Vibe101]

2007 GMY Yukon will not disconnect the tow vehicle battery when the engine is off. I know someone with a 2020 Chevy pickup and the same thing.

Leave the trailer plug in and a bad trailer battery will leave you stranded

[Larry-NC]

Just a couple of thoughts:

1) It's probably not the cause of the problem, but I'd replace that patched umbilical cord. Sooner or later it's going to give you problems. Amazon has 6-foot and 8-foot cords. Get the same size you have. Just match wire colors.
Six-foot: https://www.amazon.com/56601-Replace...%2C2399&sr=8-5
8-foot: https://www.amazon.com/ONLINE-LED-ST...%2C2399&sr=8-9
Amazon also has cords that come with a nice terminal strip at the end that makes for better connections.

2) Check to make sure you have not inadvertently pulled the breakaway switch. That can cause a high current drain on both the trailer and tow-vehicle batteries (on certain tow vehicles).