House battery draining

[dbahn]

We have a 2016 Greyhawk 29mv purchased used in October. The previous owner had installed a new house battery and it worked OK on a shake down trip that fall. I'm storing the motorhome outside (Vermont) but have been starting the chassis, and the generator every few weeks with no obvious problems, but I noticed a few weeks ago that the battery indicator showed lower voltage in the house battery (down to 1/3, with measure voltage at the battery terminal around 11.5 v) after having run it two weeks previously. I initially assumed that it must be a bad battery or that I had somehow made it that way. I pulled it out and moved it inside, but at least over the past 24 hours or so it has not lost any voltage from what I measured on removal (12.45 v).

I'm slow charging the battery now and will follow the voltage and check sp. gr of the electrolyte, but I'm wondering if there is a short that might be causing loss of voltage, even though the battery shutoff switch has always been off after running the motors.

It's cheap lead acid battery and I'm inclined to replace it for an upcoming trip but wondered if there is an easy way to test the circuits connected to the positive terminal to try to isolate the problem. I notice the power to the steps remain on with the battery disconnect off. Are there other connections that do the same?

[Jagiven]

Do you flip the disconnect switch when the MH is sitting in storage?

There are a number of items known as parasite power drains that can drain a house battery down within a few weeks. So if you are not connected to shore power, you really need to disconnect the battery, if your parked more than a few days.

If you have a battery disconnect switch, flip it. If not you an pull the neg wire off the battery terminal, or even the inline fuse at the battery.

[dbahn]

Originally Posted by Jagiven

Do you flip the disconnect switch when the MH is sitting in storage?

There are a number of items known as parasite power drains that can drain a house battery down within a few weeks. So if you are not connected to shore power, you really need to disconnect the battery, if your parked more than a few days.

If you have a battery disconnect switch, flip it. If not you an pull the neg wire off the battery terminal, or even the inline fuse at the battery.

Yes, I flip the disconnect switch when I turn off the generator and the engine. Obviously the step motor is still connected to the battery, although it shouldn't draw any power in standby mode. What else can account for parasite power?

I've thought about adding a mechanical battery disconnect in its compartment, but shouldn't that be on the positive terminal? If so there are several positive wires that connect there.

[houstonstroker]

The only way to kill all parasitic loads is disconnect the negative cable. Some safety related devices are wired directly to battery.

[Grumpy]

The steps are on the chassis battery, not the coach.

[craigav]

My steps run on either house or chassis battery. I think it may be on the same connection as the radio with the diodes inline with the harness.

Update, I will add that the wiring diagram doesn't support what I said above... I know the steps worked though when I had the chassis battery out for replacement, and same for when I had the coach battery out for replacement. However, sometimes I would jump the trigger into the aux start relay (engaging the relay) and that may be why it worked the way it did. In fact, I plan to change the momentary push switch for a toggle switch for the aux start button, that is a simple solution for me to keep the chassis battery charged.