No Electrical Power When Not On Shore Power

[johnattebury]

2021 Thor Tellaro 20LT. There is zero electrical power when not hooked up to shore power. Everything was fine until I ran my generator and air conditioner for 30 minutes, I then shut off the air conditioner and then the generator. All electrical power died - including the BMPro control panel. The solar panel indicated the batteries were dead. When I hook up shore power, everything works fine. Without shore power, there is no DC electrical power to the inverter. With shore power, there is 13 volts to the inverter, but the inverter fan is not running, which indicates to me that there is a disconnect between the house batteries and the inverter. Is there a master fuse coming from the house batteries?

 

[16ACE27]

Did you try a search for this common issue?

Search results for query: +tellaro +battery

www.thorforums.com

Could be a "disconnect". Could be dead batteries. Could be operator error.

 

[10scDust]

Stow/store switch turned off?

 

[Supercchowadventures]

There is a 50 amp breaker in line (mine is under the bed) there is a small black button on the side to reset it.
Happened to me and I was able to track it down

 

[16ACE27]

There is a 50 amp breaker in line (mine is under the bed) there is a small black button on the side to reset it.
Happened to me and I was able to track it down

A Pasadena and a Tellaro are waaay different animals.

 

[Mark54]

2021 Thor Tellaro 20LT. There is zero electrical power when not hooked up to shore power. Everything was fine until I ran my generator and air conditioner for 30 minutes, I then shut off the air conditioner and then the generator. All electrical power died - including the BMPro control panel. The solar panel indicated the batteries were dead. When I hook up shore power, everything works fine. Without shore power, there is no DC electrical power to the inverter. With shore power, there is 13 volts to the inverter, but the inverter fan is not running, which indicates to me that there is a disconnect between the house batteries and the inverter. Is there a master fuse coming from the house batteries?

For the Tellaro 20L, which I also have (mine is a 2022, so no generator)
I also have the LiFePO4 batteries- do you have the AGM or lithiums?
Check all connections, esp. at buss bars and batteries, which are underneath. What's the SOC on your Balmar? Check B- connections at shunt too. remove cover from Combi to check- 2 screws holding the cover- check those connections as well.
There is also a 250A breaker-fuse underneath (fun to get at) as well as a 50A for the 12V fuse panel from the B+ buss bar, also underneath. (2nd pic)
I've moved all that up inside my 20L (3rd & 4th pic) and upgraded to 600A. Much easier to diagnose issues now, as well as being able to remove batteries for Vermont winter storage.
I also added breaker fuses to the solar, and a 300A, B- disconnect to the shunt feed to the buss bar, for maintenance and mods.
13V is only 30% SOC, and inverter may not operate at low SOC, but that's typically 10.5V for the Combimaster. Also possible that your ReLion batteries are not working right, or has simply sat too long. Do you plug into shoreline when parked?
Also go inside the ATS box- not likely, but might be a loose wire- more likely the combimaster though. make sure inverter is actually on. I also have a mod to add a remote switch for the inverter, added below.
Helps if you have/carry a voltmeter or VOM with you.

 

[johnattebury]

Thank you to everyone to all the great advice! I've been out of town for work and just today had a chance to really spend time troubleshooting. The problem was the tripped 100 amp type III breaker. I simply reset it and everything works well. The best help was the schematic I found on the thormotorcoach.com website ... referenced in the related posts, which were recommended by 16ACE27.

 

[Mark54]

Thank you to everyone to all the great advice! I've been out of town for work and just today had a chance to really spend time troubleshooting. The problem was the tripped 100 amp type III breaker. I simply reset it and everything works well. The best help was the schematic I found on the thormotorcoach.com website ... referenced in the related posts, which were recommended by 16ACE27.

Would be helpful to have a pic of that breaker and location.
My Tellaro has no 100A type III breaker. Where is yours?
I have a 250A breaker for battery to Inverter, and a 50A type III for the 12V system connection from master switch and batteries.
Glad you found it!
PS- the schematics are helpful, but not complete- does not show regulator or shunt wiring.

 

[johnattebury]

Here's a picture of the 100 amp type III breaker. It is located underneath, on the left side, just forward of the rear tire. This is on a 2021 Tellaro 20LT with standard AGM 31 batteries.

 

[johnattebury]

Part 2: After resetting the breaker, it appears the coach batteries won't hold a charge for very long. I probably killed them by letting them stay dead for a few days. Before I buy new batteries, I'd like to make sure that there is not a parasitic draw on them. Is there any electrical component that if failed, would cause a draw?

 

[Mark54]

Part 2: After resetting the breaker, it appears the coach batteries won't hold a charge for very long. I probably killed them by letting them stay dead for a few days. Before I buy new batteries, I'd like to make sure that there is not a parasitic draw on them. Is there any electrical component that if failed, would cause a draw?

Only thing I can think of is the inverter, which can pull 50A just being on.
Make sure it's off.
And yes it's bad to leave any battery at 0% SOC for long periods, especially AGMs or lead-acid batteries. Even LiFePO4.
I'd be moving that breaker up inside. What a horrible place that is! I moved all my electrics up inside the storage under the pass. side bed. No more road grime.

 

[Mark54]

Here's a picture of the 100 amp type III breaker. It is located underneath, on the left side, just forward of the rear tire. This is on a 2021 Tellaro 20LT with standard AGM 31 batteries.

Any others? Is this on the generator feed?

 

[16ACE27]

Here's a picture of the 100 amp type III breaker. It is located underneath, on the left side, just forward of the rear tire. This is on a 2021 Tellaro 20LT with standard AGM 31 batteries.

We just call those DC Circuit Breakers. Never seen a "Type III"designation on any of them. Normally a 100 amp one is used for the generator starting/running from the house batteries.