Coach battery drain question

[Cw_chateau]

Newbie owner of a 2021 Chateau 22e and I have a question regarding the coach battery and shore power. I know to charge from shore power, the battery switch must be on. My wife turned the battery switch off with the coach plugged in to shore power, and within a week the coach battery was dead. I started doing some investigating, since I wouldn't have thought it should drain so quickly. With no shore power, and the switch off, I see about 0.1 amp drain using a clamp meter. I assume that's things like propane sniffer, display on the solar controller, etc. If I plug in shore power with the battery switch off, I see 0.6 amps of drain, which would explain a dead battery within a week (14 amp-hr per day). Why the extra battery load with shore power plugged in, but the switch off? I wouldn't have expected any difference.

Thanks for any insight.
Craig

[DavidEM]

I can't explain it either. Here is what I get with my new Axis 24.1. All amps are readings from a battery monitor I installed:

Switch off I measure a tenth or so amp so maybe 2-4 amp hours daily.

With switch on, I measure 0.7 amps which is about 15 amp hours daily. This can be cut by 0.2 amps if I turn off the outside power switch on the Girard tankless heater. I think that the BM Pro touch screen display/controller is eating up the rest.

I don't see why having shore power on or off should have anything to do with battery drain with the switch off. On my Axis there are four connections to the battery, only one of which goes through the switch: generator starter, solar power input, BIM to the chassis alternator and finally the converter fuse panel which is switched. I don't see how any of the other three un switched connections should be affected by shore power.

Mysterious!!!

David

[EA37TS]

With the switch off and connected to shore power your converter fan is still going to run. If you have an inverter it may also run unless you physically turn it off.

[Overtime]

The inverter is hard wired to the house batteries, and the inverter control current will draw power. The generator remote start and the solar cell controller also are hard wired and draw control current. The hydraulic leveling system is hard wired and will draw control current. The dash radio memory also draws from the house batteries. To totally isolate your house batteries (to keep them from completely draining while being stored) you need to unhook them (remove the negative cables from both batteries)
You can also enable the generator auto run feature to charge them.

[Cw_chateau]

I totally understand the parasitic drains on the battery. My question was why is the drain higher with shore power connected than without if the battery switch is off (.6 amps vs .1)? I would think the converter would be disconnected from the batteries since they don't charge with the battery switch off, and also that anything on the converter would be running off shore power, not the batteries. Oh, and no inverter.


More a curiosity than an issue.


Craig

[16ACE27]

Originally Posted by Cw_chateau

I totally understand the parasitic drains on the battery. My question was why is the drain higher with shore power connected than without if the battery switch is off (.6 amps vs .1)? I would think the converter would be disconnected from the batteries since they don't charge with the battery switch off, and also that anything on the converter would be running off shore power, not the batteries. Oh, and no inverter.


More a curiosity than an issue.


Craig

I recommend you go to the Thor Owners Resource page and create an account with your VIN and then download the "wiring diagram" for your coach's 12 VDC system.
Clamp-On DC ammeters are not very sensitive and can easily give false readings at under an amp of current. Are your readings repeatable?
If so, and you are indeed drawing more current with SP connected than when not and the latching relay open in both cases then I suspect it may have something to do with either the AGS if so equipped or the BIM/BIRD wiring.