Coach battery problems

[RisleyGE]

Hello Forum members,
This in my first post. February of this year we bought a 2017 Thor 27 foot class C with less than 10,000 miles. The coach battery switch got left on after cleaning the couch after our last trip in July and drained the battery, it showed 1.7 VDC. I installed a new Interstate battery this week. Nothing is getting power. I connected shore power, no help. Of course the generator will not start. I started the chassis engine and flipped a light switch. The engine instantly died and will not restart. There is an odor in the couch but it doesn't smell electrical, I was an electronics tech during my career. I have disconnected the shore power and hoping to find some help here.
Thanks, Glenn
Medford, OR

[lwmcguir]

What is the battery voltage now?

Is it installed backwards?

[Collin Kieffer]

Originally Posted by RisleyGE

Hello Forum members,
This in my first post. February of this year we bought a 2017 Thor 27 foot class C with less than 10,000 miles. The coach battery switch got left on after cleaning the couch after our last trip in July and drained the battery, it showed 1.7 VDC. I installed a new Interstate battery this week. Nothing is getting power. I connected shore power, no help. Of course the generator will not start. I started the chassis engine and flipped a light switch. The engine instantly died and will not restart. There is an odor in the couch but it doesn't smell electrical, I was an electronics tech during my career. I have disconnected the shore power and hoping to find some help here.
Thanks, Glenn
Medford, OR

I'm replacing my 2 original Class C Coach batteries and considering Renology AGM 12V 100amp/10hr. batteries. Any thoughts on this battery or any recommendations on replacement of my original batteries? I'm not interested in Lithium or Flooded Lead Acid. I reside in Phoenix, AZ & San Diego in Summer (June-Aug.) so I do need to batteries to withstand the heat as Coach is stored outdoors when not in use. Thanx for any thoughts & suggestions.

[RisleyGE]

Thank you for the reply.
The new battery was at 11.9 volts when only the positive side was connected. It is installed correctly.

[RisleyGE]

I have read about the BIM. Any idea how I can locate it? Or what it looks like? I slid under the coach but could not see anything that looks like an electrical device. I understand Thor does not have schematics to help troubleshoot the coach.

[16ACE27]

Originally Posted by RisleyGE

Thank you for the reply.
The new battery was at 11.9 volts when only the positive side was connected. It is installed correctly.

Are you sure? Did you take pictures and label all connections before disconnecting and removing the old battery?

Thor has no standards on battery cable colors and sprays a red corrosion prevention spray on all connections so if you are relying on color standards you are SOL.

Having the engine die as soon as you engaged a load indicates a direct short.

There should only be a single cable on the negative post going directly to chassis ground. All other battery cables (could be 4 or more) should go to the positive post.

Once you resolve the connection problem, you'll be on to finding the DC breakers that may have tripped and the fuses (including the reverse polarity fuses) that may have blown; both on the house side as well as the chassis side. And then check the converter's AC breaker to make sure it didn't trip.

Hopefully the converter and alternator were saved by the breakers and fuses.

[Lt Keefer]

I would look for rodent damage. Start at each battery and inspect as much of the wires as possible. It can be a long process and you may have to open some closed/sealed areas. I had to do it on my last coach. Stupid tree rats.

[Redsand]

Originally Posted by Collin Kieffer

I'm replacing my 2 original Class C Coach batteries and considering Renology AGM 12V 100amp/10hr. batteries. Any thoughts on this battery or any recommendations on replacement of my original batteries? I'm not interested in Lithium or Flooded Lead Acid. I reside in Phoenix, AZ & San Diego in Summer (June-Aug.) so I do need to batteries to withstand the heat as Coach is stored outdoors when not in use. Thanx for any thoughts & suggestions.

We replaced our single house battery group 27 deep cycle with two Renogy AGM 100ah flavor batteries. So far very pleased with performance. We dry camped our first night with lights TV and propane furnace all running for maybe 4 hours and our Renogy shunt monitor showed 91% at bedtime and 85% in the morning. Your supply may vary but so far just right for our needs. Nice upgrade and midway to lithium system upgrade cost wise.