Battery Problem

[Webster]

After about 5 days of sitting, my starter battery won't start the motor. I use the booster and it starts right up. I ensure that the 12v switch by the door is turned off when I leave it. The radio is off. Is there another source draining the battery? I had someone mention that the starter battery charges the house batteries and that it might be hooked up wrong? Can't figure out the drain. Anybody got some ideas?

[Webster]

After about 5 days of sitting, my starter battery won't start the motor. I use the booster and it starts right up. I ensure that the 12v switch by the door is turned off when I leave it. The radio is off. Is there another source draining the battery? I had someone mention that the starter battery charges the house batteries and that it might be hooked up wrong? Can't figure out the drain. Anybody got some ideas?

[wilanddij]

Even though you think you have disconnected the chassis battery via the relay cutoff, there is still stuff that pulls power from it. After toasting one chassis battery by letting it totally discharge in storage, I've installed one of the knife type disconnect switches to the ground side of the battery. This ensures that I don't have any parasitic drain on it.

[Webster]

Hmmmmmm....that sounds good, but I'm not an electrician. Where can I find out how to put in a knife switch?

[wilanddij]

Camping World sells them for about $20. Do a search on their website. Installation instructions come on the package. Basically, all you do is disconnect the negative cable from your battery, connect the switch to the battery, and reconnect the cable to the other side of the switch.

[Rob Hentges]

I think those type of switches should be available at just about any auto parts store, and maybe even in the auto battery section of walmart.

[Stan Birch]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Webster:
After about 5 days of sitting, my starter battery won't start the motor. </div></BLOCKQUOTE>
I can leave my rig sitting for 5 months; and it will still start.

&gt; ensure that the 12v switch by the door is turned off when I leave it.

That switch probably has nothing to do with the chassis battery . . . just the coach batteries.

&gt;Is there another source draining the battery?

From what you've described, it might very well be that your chassis battery is due for replacement. If it is okay, then you'll have to track down the culprit by connecting an amp meter between the chassis battery and cable; and then start pulling fuses until you determine which circuit is causing the current-draw. The normal standby current for Ford products is &lt; 50 ma.

[Webster]

This is a used vehicle, but the chassis battery is new. I find it difficult to believe that the previous owner had this problem all the time. Not being a electrician, I find the ampmeter I have a bit difficult to understand. I think the knife switch is a good idea. I'll look at Wally World next time I go over. If not, then I'll go to Camping World in Bakersfield. Need to stop over at Lemoore NAS anyway.

[Kirk]

If the battery is actually new and in good condition, there is a serious problem that you do need to correct. The chassis battery does not charge the coach batteries nor is it in any way connected to the coach when the engine is nor running. The fact that you coach batteries will start the engine is proof that the problem is not with them. If there is only one battery isolator switch at the door, it most likely does not open the power to or from the chassis battery. If you have electric steps, they would get power from the chassis battery and could be a part of the problem. It isn't a bad idea to put in an isloation switch for the batteries, that really is a very poor way to deal with the problem since you will have to open it even when you travel or the battery will go down. You need to find what is draining the battery. An easy way to test the battery to be sure that the battery is good would be to lift the neg. cable from the battery. If it will then start the coach after it sits for a week, they you know it is a leakage problem But to really know anything about this problem, you need to get a meter and learn to use it. Otherwise you are just groping around in the dark!

[Stan Birch]

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Kirk:
If the battery is actually new and in good condition, there is a serious problem that you do need to correct. . . . It isn't a bad idea to put in an isolation switch for the batteries, that really is a very poor way to deal with the problem . . . . You need to find what is draining the battery. </div></BLOCKQUOTE>
I fully agree with Kirk!

If your battery is running down that fast, then you have a defective electronic component in the system which is drawing current when it shouldn't . . . like a leaky alternator diode, any one of various electronic modules, including the PCM or step controller. It's not going to improve over time, but will very likely get worse; and possibly leave you stranded on somewhere on the road. Best to address this situation while you are at home; and if you can't find the problem, then it's important to have it checked out by a pro. On a best-case scenario, it may be nothing significant; worst case, you could fry your wiring and end up with a fire.

[Vet Man]

I had the same problem and after talking to others I have found that the power step is on the Chassis battery, the lighting in the driver and passenger area, and the slide motors. I was operating the slides after the engine was off running the battery down. The wife used the overhead lights in passenger seat to read. Vet Man

[Webster]

I didn't think it was supposed to do this. Guess I had better take it in for service to find the problem before it gets worse.

Thanks so much for all the info.