Troubleshooting Battery Drain With A Roadmaster Invisibrake When Idle

Published 03/12/2024

Question:

Why is my car battery being drained when just sitting with the invisibrake is set to the off setting? Also my car battery will not charge in the car with the switch on or off. I have replaced two batteries with in 6 months in my 2018 ford focus. Please let me know what’s going on.

asked by: Brenda

Wiring
(click to enlarge)

Expert Reply:

Hi Brenda,

The Invisibrake # RM-8700 will have a tiny pull on the battery, but shouldn't pull enough of a charge to drain it when in idle mode. This leads me to believe it was either installed incorrectly or that you might have an issue with the breakaway switch. If the breakaway switch is faulty the unit could be trying to activate the brakes even though it's just sitting there. I would pull the plunger out of the breakaway switch and then place it back in, making sure it's fully in place.

I would also print out the wiring diagram for the Invisibrake and trace the each wire to ensure everything was properly installed. I would also check that you don't have anything else running to the battery that could be draining it. I see a few different wires connected to the battery terminal in the picture you provided so those could potentially also be the cause.

From there I'd check the alternator in your Focus because the battery should be charging while you drive. It could potentially be going out and the Invisibrake is just taking the blame.

Let me know what you find and we can keep troubleshooting.

expert reply by: Kevin C

Kevin C.

3/12/2024

The wires I believe you saw were from my battery being disconnected. We bought the every and car from someone that had it professionally installed. The car had only been towed a few times since April of 21- to Oct 21. And hadn’t been towed since. I didn’t know about an on off switch until April of 22. The car has been driven a few times since then, but mostly sits in the garage. My son tried to charge the battery while in the car, but it wouldn’t charge. but once he took it out it was getting a little charge. That’s when I replaced to 1st battery that was installed Jan of 22, then replace that on in Aug of 22. Because it was dead again and wouldn’t that a charge, it was dead again in less than 2 weeks after it was used for a week. When my husband was around I never noticed he had shut the on off switch off to use the car when he drove it weekly. I will have my son look at the wiring diagram. Any additional info would be great, I don’t know what else could be draining it, sitting in the garage. Brenda

Kevin C.

3/12/2024

@Brenda The battery disconnect is needed while flat towing but there's other wires running to the battery post that we don't know about. You'd want to trace those wires and see what they go to and we can deal with the issue once it's found. The smaller wires are after the disconnect so they will still get power regardless of whether the disconnect is on or off so they are the likely culprit. That being said, there is no certification requirement to install flat towing components so there's also the chance the something was installed incorrectly. Speaking from experience, the instructions from the manufacturer aren't the best so if you don't know exactly what you're doing it's very easy to do it wrong. With it sitting for long periods of time it's hard to pin point the issue fully so I'd try starting it and running it for a few minutes every other week at least. I'd also have the alternator checked out.