Batteries

[Poppymike]

I have recently replaced the coach batteries in my 2017 Quantum class C motorhome. My problem is the batteries will not stay charged. Any help will be greatly appreciated.

[16ACE27]

Did you replace them?
Did you take pictures and label cables before removing them?
Are all the cables back in their proper place?
Was the converter on when replacing?
Have you verified the 50 amp circuit breaker near the batteries is not tripped?
Is the battery disconnect shut (USE/STORE switch in USE)?
Have you checked that the reverse polarity fuses on the DC distribution fuse panel are not blown?
Have you verified the converter 120 VAC breaker is not tripped?

[Poppymike]

Thanks for the reply.
Yes I replaced them, and yes the cables are on properly. I didn't take pictures and wasn't sure about placement so I went to the dealer and asked about proper placement.
The rest of the items, unfortunately I really don't know what you are talking about. Really didn't get to use it much due to Covid.

[OldWEB]

So if you have a DC voltmeter, start taking voltages at the batteries, with and without SP on; DC voltages at the breaker/fuse panel, noting the terminal (as there are more than one) and again with and without AC power applied.

[Poppymike]

I can defiantly do that. Think this is going to turn into one of those situations where you try to save money and ends up costing more.

[dkoldman]

Originally Posted by Poppymike

I can defiantly do that. Think this is going to turn into one of those situations where you try to save money and ends up costing more.

I think you can get better help if you just share more information or at least provide better context so others may try to help figure out what happened?

What was going on with the old batteries?
Was everything working before batteries came out?
What kind of batteries did you buy and where from?
Did you install them or have someone else install?
All you say is battery will not stay charged? No battery will stay charged. You have to say how long before it discharges and what draw may be on it.

I hope you take the questions as trying to help so you will take the time to provide more info.


Here is example, I could buy the best quality batteries possible, have a professional install and be 100% assure they were installed correctly and have the exact same problem as you described. How? Imagine if I had my fridge on and it was on my inverter which draws from batteries, my batteries would discharge in less than 4 hours.

[Poppymike]

You’re right, sorry about the lack of information. Nothing will work off the batteries. Shore power is fine, generator is fine. Shut generator off, everything will turn off until I plug the shore power back in. The batteries are less than a year old. I had to replace both 40 amp fuses. None of the breakers are tripped as far as I can tell. All other fuses test fine. I was reading that Thor doesn’t use inverters? Don’t know how that works, but ok. Don’t know where else to go with this other than a mechanic.

[dkoldman]

Originally Posted by Poppymike

You’re right, sorry about the lack of information. Nothing will work off the batteries. Shore power is fine, generator is fine. Shut generator off, everything will turn off until I plug the shore power back in. The batteries are less than a year old. I had to replace both 40 amp fuses. None of the breakers are tripped as far as I can tell. All other fuses test fine. I was reading that Thor doesn’t use inverters? Don’t know how that works, but ok. Don’t know where else to go with this other than a mechanic.

I think your issue will be simple, once we isolate exactly what is root cause.

Here is what we know. ( I think?)

1. When on Shore or Generator everything works That is likely because your converter is taking 120VAC and sending 12vdc to your bus. So you are good there.

2. All of your 12vdc items are proven to work correctly as long as 12vdc is supplied to the buss.

3. Nothing has changed with your wiring recently, this issue just occurred and was working previously.

So your issue is why your batteries cannot supply your 12vdc buss?

Here what I would do.

Make sure use switch stays on in Use mode.
Disconnect Shorepower and no genny running.
Measure voltage of House batteries
Measure voltage on 12vdc buss bar, it is probably close to where your 12vdc breakers are. the voltage should be the same.

My guess is the batteries are dead, but you may have issue with the trombetta relay?

But your problem is between the batteries and that 12vdc buss. Just need to be patient and start measure voltage at one place to the next to see what is dead, or defective.

Thor does install Inverters, but it is not available on all coaches., I suspect if you had one, you would know; so we assume it is not on your coach.

[16ACE27]

Originally Posted by Poppymike

Thanks for the reply.
Yes I replaced them, and yes the cables are on properly. I didn't take pictures and wasn't sure about placement so I went to the dealer and asked about proper placement.
The rest of the items, unfortunately I really don't know what you are talking about. Really didn't get to use it much due to Covid.

So you think the cables are on properly because you are sure you understood what the Dealer told you and are sure their information was correct.

Sorry, can't put a lot of faith in that statement. I gave you a list of possibilities. Tackle them one at a time to eliminate each one as the problem. Don't eliminate one unless you are truly sure it can't be the problem. If you don't understand any of the possibilities, ask specifically about that item in this thread until you can accurately check it and eliminate it as the problem. Then move on to the next possibility.

All the things have to be good and work correctly for things to work.
It only takes one faulty item to stop things from working.

[Travelin' Texans]

Here's the proper connections for 2 or more 12 volt batteries wired parallel.
Wire colors may be different on your rv, possibly white & black, black +, white -.

[16ACE27]

Originally Posted by Travelin' Texans

Attachment 37500
Here's the proper connections for 2 or more 12 volt batteries wired parallel.
Wire colors may be different on your rv, possibly white & black, black +, white -.

Way too simplistic for a Thor install. Multiple cables are connected to the same posts, cables are not marked and all are black with red spray on them, no white or red cables to be found.

[Travelin' Texans]

Just in case 6 volts are being used.

[cgeace29.3]

Be shure to unhook the negative cable at the battery when not using motor home

[BattleBorn1]

When mine acted this way after a battery change out, I had to replace the inverter. Good luck

[ducksface]

Simplified Thor typical
(I suggest you all screen shot this)

[lwmcguir]

PoppyMike must have blown his rig up charging the batteries

[16ACE27]

Originally Posted by lwmcguir

PoppyMike must have blown his rig up charging the batteries

Yep. Ghosted since his last reply.

[ducksface]

Yeh, my diagram was more for everyone reading this thread in the future.
The drive-by, me me me posts are getting thicker.
So few follow through.

[dkoldman]

I was hoping to learn where are the two 40 amp fuses he replaced?

I think the statement he made "Think this is going to turn into one of those situations where you try to save money and ends up costing more." was telling.

I am gonna go out a limb and say he didn't buy Lithium or AGM batteries here; so if he gets two FLA what did he do to save money? Did he buy used FLA batteries? What if his problem is EXACTLY what he said it was in Post #1? "I have recently replaced the coach batteries in my 2017 Quantum class C motorhome. My problem is the batteries will not stay charged." So now he realized his batteries were no good so he is beginning to believe he must now go buy brand new FLA Remember he said the replacement was less than a year but didn't mention a warranty.

[16ACE27]

Originally Posted by dkoldman

I was hoping to learn where are the two 40 amp fuses he replaced?

I think the statement he made "Think this is going to turn into one of those situations where you try to save money and ends up costing more." was telling.

I am gonna go out a limb and say he didn't buy Lithium or AGM batteries here; so if he gets two FLA what did he do to save money? Did he buy used FLA batteries? What if his problem is EXACTLY what he said it was in Post #1? "I have recently replaced the coach batteries in my 2017 Quantum class C motorhome. My problem is the batteries will not stay charged." So now he realized his batteries were no good so he is beginning to believe he must now go buy brand new FLA Remember he said the replacement was less than a year but didn't mention a warranty.

He "saved money" by replacing the batteries and installing the new ones himself.

The 40 amp fuses are the reverse polarity fuses on the Power Center. The fact that he had to replace those tells me the new batteries were not initially connected properly despite his insistence they were. I suspect he went back and did some more investigating, found another connection issue (or lack of connection issue), fixed it, but is too embarrassed to come back and give us the resolution.

Nope, never seen that before.......