Magnitude House battery issue

[BrenKristy]

Hi Everyone,

Newbie RVer here and my first post on this forum so please excuse and educate me if i'm breaking rules or protocols with this.

My wife and I just bought a new 2021 Thor Magnitude BH35 last August (Camping World, Syracuse NY), and have only had the opportunity to take it out a couple of times before needing to have several problems fixed. The unit has now been at the service shop (CW, W Hatfield, MA) for more than three times as long as the time i've had it in my possession to use. So I'm really hoping to have all of the major problems fixed before getting it back from the shop this time.

One of the reasons I had to take the unit to the repair facility was that when I had the unit parked and not connected to shore power, the house batteries would drain to about 10V in about 24 hours even with no lights or appliances being powered. At this point it would be impossible to even start the generator without starting the engine of the truck. I called the Thor warranty support and they said that this was abnormal and needed to be fixed. However, at the repair facility, they are not able to replicate the rapid battery drain that I experienced. Being inexperienced myself, I'm not sure if I'm doing something wrong or is there an actual problem due to an unexpected power drain from the unit when parked. The only difference (I assume) from what i did versus the repair shop, is that I had the unit on the leveling jacks when parked with the automatic leveler turned off after the unit was leveled.

Any insights on what I might be missing?

Thanks in advance for reading and your thoughts.

Brendan

[Grumpy Grampa]

Just a thought. Make sure you are using shore power, Plugged in. Make sure your use/storage switch is on. Your batteries will charge . It will take awhile.

[BrenKristy]

Originally Posted by smithgarnat@aol.com

Just a thought. Make sure you are using shore power, Plugged in. Make sure your use/storage switch is on. Your batteries will charge . It will take awhile.

Thanks for your reply.
Actually I don't have a problem with recharging the batteries, but it's just that they drain very quickly even when I'm not powering anything and the unit is parked.

[Grumpy Grampa]

You may know this. When not using RV have unit in storage mode.

[Grumpy Grampa]

Couple thoughts.
Inverter off, and in storage mode and they still drain?

[BrenKristy]

yes, they still drain with the inverter off.

I'm researching this storage mode to see if that changes things. But oddly enough, at the service place they are not able to replicate the battery draining problems I've experienced. While it could very well be something lame like they have the unit connected to shore power while testing(I wouldn't put it past them), but I'd like to give them the benefit of the doubt and find out if i'm doing something wrong first.

[16ACE27]

Your unit has a house battery disconnect AKA USE/STORE switch or Main Power switch.

When not plugged into SP that switch should be in STORE (battery disconnected) to prevent house batteries from draining due to always on loads.

BUT: even with it in USE (batteries connected) and nothing running, your house batteries still should not drain that quickly, especially if your inverter is off.

Don't put it past the dealer to do exactly as you suspect. They should be conducting 2 tests:

Charge and LOAD TEST the batteries to see what their true condition is. Many MHs have their house batteries abused on the dealer lot and get delivered with damaged house batteries.

Static current draw - measure the current draw from the house batteries NOT PLUGGED INTO SP with everything turned off. Should be less than an amp.

An often overlooked "phantom draw" is lights left on in the storage compartments.

[BrenKristy]

Originally Posted by 16ACE27

Your unit has a house battery disconnect AKA USE/STORE switch or Main Power switch.

When not plugged into SP that switch should be in STORE (battery disconnected) to prevent house batteries from draining due to always on loads.

BUT: even with it in USE (batteries connected) and nothing running, your house batteries still should not drain that quickly, especially if your inverter is off.

Don't put it past the dealer to do exactly as you suspect. They should be conducting 2 tests:

Charge and LOAD TEST the batteries to see what their true condition is. Many MHs have their house batteries abused on the dealer lot and get delivered with damaged house batteries.

Static current draw - measure the current draw from the house batteries NOT PLUGGED INTO SP with everything turned off. Should be less than an amp.

An often overlooked "phantom draw" is lights left on in the storage compartments.

Thank you so very much for the suggestions on the tests to be run. I called the service shop and asked to run the tests, although I suspect you comment on the battery being shot is accurate because the MH was on the dealers lot for 7 months before we purchased.
Much appreciate the advice.