coach battery discharge/dc control breaker

[Joseph Stefko]

I have a 96 Monaco and the coach battery is hot with the cut-off switch in the off position. I don't have cargo bay lights on. Does anyone know why the battery would be drawing power with the main switch (by the door) in the off position? I know the switch is working because there is enough juice to turn my xm portable radio on and when I put the switch to off the radio goes off.

I am new to this but have a good understanding of how dc/ac work. Also after attempting to start the generator last night, it turn over and I did not use preheat and when I went to try it again (7.5 onan gen) the DC control breaker triped. Is there any relationship between this and the battery drain. It is my understanding that the coach battery starts the generator. Everything worked fine on my 1300 mile trip prior to setting up camp yesterday. Would low voltage on the battery cause this to trip? Thanks for your help. Joey

[Joseph Stefko]

I have a 96 Monaco and the coach battery is hot with the cut-off switch in the off position. I don't have cargo bay lights on. Does anyone know why the battery would be drawing power with the main switch (by the door) in the off position? I know the switch is working because there is enough juice to turn my xm portable radio on and when I put the switch to off the radio goes off.

I am new to this but have a good understanding of how dc/ac work. Also after attempting to start the generator last night, it turn over and I did not use preheat and when I went to try it again (7.5 onan gen) the DC control breaker triped. Is there any relationship between this and the battery drain. It is my understanding that the coach battery starts the generator. Everything worked fine on my 1300 mile trip prior to setting up camp yesterday. Would low voltage on the battery cause this to trip? Thanks for your help. Joey

[MikeT]

You could have a shorted cell in the battery. There also could be a heavy drain or short between the battery and the cut-off. You need to try to determine if there is a current draw on the battery, you can do this with a clamp on type ammeter.

[Gary RVRoamer]

Yes, low voltage can cause a breaker or fuse to trip. An electric motor (such as a starter motor) needs a certain amount of power to operate and when the voltage is low the amps have to increase to compensate. If they increase enough, the breaker will trip.

There may be several things wired direct to the battery, bypassing the disconnect switch. Likely candidates would be propane and CO detectors, the disconnect switch itself (needs power to re-connect), slide out motors, power steps (usually on chassis battery), and any dealer or owner added accessories.

Some coaches wire the genset starter to the chassis battery and some to the house battery. You should also have an emergency (or auxiliary) start switch that temporarily cross connects the two battery banks to allow one to provide power to the other if needed. The connect lasts only while the switch is held down.

[visch1]

In my experience it’s called parasitic drain. Even with the coach switch off things are on, the power steps probably still work along with the carbon monoxide detector. Having that switch off in my unit for a month resulted in totally drained coach batteries. To overcome this I installed a KNIFE on/off switch on the negative wire going to frame ground and each time I’m not going to use the unit for awhile throw the switch open. Mine is easy access. There a # of types of switches but this is a very simple one that works. Be aware there are a few connection types to choose from, post, screw etc.