Thor Ace severe chassis battery drain problem.

Hi to all of you.

New here. Please excuse the rambling length of this post but, a little history may shed some light on my problem.

We purchased a 2013 Thor ACE that was 1 yr old w/8k miles back in 14. Love it. Fun to drive (although it is not the best in fuel econ) well laid out and had no major problems, or so I thought, until now. We had our chassis battery die on us about 11 months into our ownership. Fortunately, it did not happen on the road. I try to start and run our ACE at least 3-4 times a month just to keep the battery topped off. However, at that point the battery died and no attempts at jumping helped. It took ordering a solar charger and leaving it hooked up for 2 weeks to get it back to a sustainable level to start with the chassis battery only. I have since done the same with the coach batteries, just in case.

We took the RV back to the dealer and they inspected and tested the battery and ended up replacing it with a new one. No biggie. Everything was fine for the next year. I always kept the solar panel hooked up and she would start with no problem. Well, back in January, the problem reared its ugly head again. Instead of taking it to the dealer (knowing they would bend me over. They are a used dealer not a biggie), we took it to the local Camping World here in Ocala, FL.

CW discovered that the solenoid in the power control center was bad (this control unit was a cause for a recall on the Thor ACE. The factory and the Control Unit Mfr. both agreed that the "fix" was to simply bypass the solenoid. Cheap!). So, they ordered a replacement and installed it, charged the batteries and everything tested out fine. We picked it up, brought it back to our community storage lot and parked it. the following weekend I retrieved it and parked in front of our home for some minor maintenance and left it running while I worked (just in case). I returned it to our storage lot, parked and went home.

The following weekend I went to bring it back to the house and it would not start. The battery was drained again. So I tried using the coach battery emergency start and nothing. I soon discovered the Coach battery circuit breaker had tripped. I reset it and of course it started. The chassis battery continues to drain if left for more than 7 days, even if you have it hooked up to the solar panel. Camping World, after having it for 2 weeks, tells me nothing is wrong. It is nothing they did they say. OK, then what is it I ask? Well, we have no idea."Our tech says that if you let a battery go for more than 7 days without charging it it drains."  Horse Hockey! Something has to be killing the battery.

Has anyone had this type of problem? If so, any clue to where I might begin checking for a solution? Camping World seems to be baffled and afraid to admit it. Hence, the cover your butt answer. The problem did not start with them, but something is draining the battery. I am tempted to install a Battery disconnect switch and isolate the battery completely and keep it trickle charged with the solar panel if I have to. If anyone has had similar problems, how did you handle your search for the culprit? Any input would be appreciated.

Tom

It's not unusual for modern coaches to drain batteries fast - lots of electronics that stay alive. Usually the house battery is more of a problem, though.

Basically the search involves opening circuits one at a time to see what has an effect on the problem. Remove a fuse or flip a breaker and check the result, either with a amp meter on the battery post or just wait a week and see what happens.

The entry step is powered from the chassis battery, so it its light (may or may not have this) stays on, that will surely run the battery down. And sometimes installed accessories get wired to the chassis battery and can cause the problem.

I killed my chassis battery with the stereo one time.  Seems that switch on the dash doesn't hook it to the house batteries like I thought it did.  :-[

Your not doing the engine any favors by running it frequently to charge the battery. Unless you drive it long enough to bring the engine and transmission fully up to temperature, you're better off not starting it all.

Something obviously changed if it was okay for almost a year. Are there any shops around that specialize in automotive electrical, not necessarily RVs? We've got one near us and I've heard some great stories about problems they have been able to track down.

We also have a Thor Ace (2016) and have had almost the same problem. The original chassis battery was fine for about a little more than a year. Then it started dying while we were parked at an RV park. We replaced the battery and it still does while parked. The only thing that saves it is to disconnect the negative battery post while camping.  I have heard that it could be a bad diode in the alternator, or a short in the solenoid connected to the emergency start (that also doesn't work.)
I'm just about ready to take it to an electrical shop to trace the problem. If anyone knows for sure let me know, otherwise I'll post the solution if I find out.

A quick, easy and inexpensive fix is a battery disconnect like this.

https://smile.amazon.com/NOCO-ID220S-6V-24V-Battery-Disconnect/dp/B006EH9WUC/ref=sr_1_7?ie=UTF8&qid=1533426539&sr=8-7&keywords=battery+disconnect

It will prevent battery drain from external sources, but it will also reset every electrical device in the RV, including clock. radio memory (may need reset code) and the on board engine computer.

central67 said:

I'm just about ready to take it to an electrical shop to trace the problem. If anyone knows for sure let me know, otherwise I'll post the solution if I find out.

Click to expand...

Since it sounds like this isn't a fluke affecting only one machine, but maybe a known problem affecting many machines, I'd go to a Thor Owners forum to inquire about it.  It's almost a cinch bet someone there knows the answer.

A Google search on "Thor RV Forum" turns up a couple of different Thor forums

I had the same problem with my Thor, but of an older vintage.  Is anything plugged into the cigarette lighter/external dash power?  That could do it.

Let me be the first to welcome you to the forum.

central67 said:

We also have a Thor Ace (2016) and have had almost the same problem. The original chassis battery was fine for about a little more than a year. Then it started dying while we were parked at an RV park. We replaced the battery and it still does while parked. The only thing that saves it is to disconnect the negative battery post while camping.  I have heard that it could be a bad diode in the alternator, or a short in the solenoid connected to the emergency start (that also doesn't work.)
I'm just about ready to take it to an electrical shop to trace the problem. If anyone knows for sure let me know, otherwise I'll post the solution if I find out.

Click to expand...

Just got my RV back from the electrical people and they say it was a defective ISO delay relay. They removed the ISO delay relay and rewired it with a key.
The emergency start solenoid was stuck in the on position draining the chassis battery.
When I got home I found that the backup and turn signal cameras did not work. (Radio either) I had noticed that they worked intermittently before I took it in. So I took it back and am now waiting for a new invoice after the first one for $361.90. These things are not built with the finest electronic parts and workmanship!  I am also hoping that my extended warranted for the Ford chassis, or the extended warranted for the coach will cover it.  Film at 11:00!

central67 said:

Just got my RV back from the electrical people and they say it was a defective ISO delay relay. They removed the ISO delay relay and rewired it with a key.
The emergency start solenoid was stuck in the on position draining the chassis battery.
When I got home I found that the backup and turn signal cameras did not work. (Radio either) I had noticed that they worked intermittently before I took it in. So I took it back and am now waiting for a new invoice after the first one for $361.90. These things are not built with the finest electronic parts and workmanship!  I am also hoping that my extended warranted for the Ford chassis, or the extended warranted for the coach will cover it.  Film at 11:00!

Click to expand...

The electrical shop found that I had my coach power switch off. Turn it on and cameras and radio work. Problem was the ISO delay relay.

you could try this.. for $14.

throw it up on the inside of the windshield, plug it into the dash cigarette lighter...and you're done.  the battery should never go dead.

(check to see if your lighter stays hot when the key is off)

https://www.harborfreight.com/15-watt-solar-battery-charger-68692.html