House Batteries discharge

[Prairie]

The house batteries on my 2010 AI (2008 MB Sprinter chassis) discharge after about two weeks of non-use even with the battery "switch OFF" and no load on them. Batteries are two Interstate SRM 24 new in Jan 2014. Any suggestions?

[acstokes]

There are a number of electrical devices that drain power even when the disconnect switch is in the off or store position. These constitute what is know as a parasitic load. Either disconnect your battery cables completely, use a trickle charger to maintain the batteries, or leave your trailer on shore power.



Sent from my iPhone using Airstream Forums

[Moflash]

I always disconnect mine and connect battery tender to mine when in storage.LP gas leak detector is a culprit but there are more.

[Boxster1971]

Not sure how much parasitic drain there is on your 2010 AI, but if it takes that long for it to drain the batteries it can't be much. My 2013 has a constant 0.4 Amp drain that empties the batteries in a few days. As suggested disconnect batteries or use a trickle charger. The disconnect switch does not cut power to things like the propane alarm or the smoke/CO alarms.


- - Mike
2013 Lounge EXT on 2012 Sprinter

[Prairie]

Thanks for the responses. It's about what I expected. Trouble is it's a real pain in the ass to get to the batteries under the lounge seat. How about removing a fuse in the DC panel to disable the circuit that serves the parasitic load?

[acstokes]

That will work as long as there's nothing else wired directly to a battery.




Sent from my iPhone using Airstream Forums

[Protagonist]

Originally Posted by Prairie

Thanks for the responses. It's about what I expected. Trouble is it's a real pain in the ass to get to the batteries under the lounge seat. How about removing a fuse in the DC panel to disable the circuit that serves the parasitic load?

On the 2010 Interstate, the propane solenoid might bypass the main disconnect (not sure what year they fixed that). That would be about a 0.75 amp draw, or 18 amps per day. With two house batteries totalling 160 to 168 amp-hours, your house batteries could be stony dead in about 9 days from that draw alone.

Another possibility would be if you have left the inverter turned on. You have to shut off the inverter as well in order to prevent parasitic loads on the AC side, such as your television(s), which draw some power even when turned off. Note that even in "charge only" mode the inverter/charger will draw some power, for monitoring the batteries and its own cooling fan; it has to be "Off" to eliminate any draw from that source. Since the remote control doesn't have an "Off" position you have to do it from the switch on the front of the inverter/charger under the sofa.

Yet another possibility is the antenna amplifier in the full-width compartment over the driver's seat. On older Interstates, the amplifier isn't shut off by the battery disconnect, either, and so has to be shut off separately.