Charging System Issue

bigben · 02-08-2018, 01:31 AM

I've had an issue develop with our coach. It seems I am not getting a charge from either the automotive alternator or the on board Onan 5.5 KW. Xantrex remote status indicator shows 11.9 volts with both of these running. Some charging voltage must be getting through but not getting to 13+ range. After a discussion with Thor CSRs and looking at the wiring diagrams, I plan to conduct some tests.

1. Check voltage at e-start solenoid after disconnecting from house batteries - should be the same as voltage output from automotive alternator (13+ range).

2. Check voltage at inbound side of 100 amp breaker (with breaker open) while running generator. Voltage should be 13.2, 13.6 or 14.2 volts dependent on convertor state.

3. Run load tests on individual house batteries looking for a dead cell battery.

If I have thought through this process correctly, I should find the issue. Either a bad e-start solenoid, converter and/or battery.

I've uploaded the wiring diagram.

Fellow DIYers, please read the above and look at the attached pdf and give me your inputs.

Thanks.

**16ACE27** · 02-08-2018, 01:40 AM

Are we talking house or chassis batteries? Or both?

Does anything charge when plugged in to Shore Power?

bigben · 02-08-2018, 01:46 AM

We are talking house batteries and yep - the 110 side of the system is working great.

**16ACE27** · 02-08-2018, 01:53 AM

Then you have 2 different problems:

1 - The Generator is not powering the converter to charge the battery. It uses the same converter as the Shore Power connection.
2 - The cross-connect circuitry that allows the Alternator to charge the house batteries is not working. Does it work the other way? If on Shore Power with the engine off does the converter charge the chassis battery?

bigben · 02-08-2018, 02:06 AM

Tfryman - yep. Actually there is a 3rd possibility - bad battery. The steps I listed above are intended to test for both of your suggestions. So it sounds like you agree with me. I am beginning to believe more and more that it is the batteries - it is the single common point.

**16ACE27** · 02-08-2018, 02:11 AM

Quote:

Originally Posted by bigben

Tfryman - yep. Actually there is a 3rd possibility - bad battery. The steps I listed above are intended to test for both of your suggestions. So it sounds like you agree with me. I am beginning to believe more and more that it is the batteries - it is the single common point.

Nope. A bad battery would give the same symptoms on both Shore Power and Generator operation. You said " the 110 side of the system is working great" in response to my question about it charging on shore power. Is that what you meant? Because in reality, the 110 side of the system is not working great if the batteries charge on Shore Power but not on the Generator.

bigben · 02-08-2018, 02:15 AM

Yep - batteries not charging with either on board generator or automotive alternator. On board generator IS powering all on board 110 outlets just fine. Voltage is not getting to the house batteries, thus the test at the 100 volt breaker.

All this discussion is helping me test the process for isolating the issue. thanks

**16ACE27** · 02-08-2018, 02:22 AM

OK, one more time:

When the coach is plugged into Shore Power do the house batteries get charging voltage? "Voltage should be 13.2, 13.6 or 14.2 volts dependent on convertor state."

bigben · 02-08-2018, 02:27 AM

Tfryman - shore power is not available, only my on board generator. I believe the effect should be the same with both breakers on the Onan in the on position. Power (110 volts) to the buss bar/breaker box, power out to the converter, 12 volts out from converter to the 100 volt breaker. Voltage out from batteries to inverter - at least that is the way I read the wiring diagram.

**16ACE27** · 02-08-2018, 02:34 AM

OK, do both Air Conditioners run on the generator? Just trying to eliminate the Automatic Transfer Switch and wiring as a possible problem. It is a Thor after all and many have found poor connections at the ATS.

bigben · 02-08-2018, 02:44 AM

Ted - I will check tomorrow. Unfortunately, we are FREEZING cold here in KY vs. being in Key West - where we've been the last 3 winters. Consequently, we only used the microwave. Like I said, I'll check it tomorrow and let you know outcome.

Oneilkeys · 02-08-2018, 03:10 AM

I’m not sure this is applicable to your large Class A, but do you have 50 or 100 amp breakers that separate the coach and chassis batteries from the charging systems. I would think that you do. Something else to check.

bigben · 02-08-2018, 01:43 PM

Yep - the coach has three of them, even using one of them in the "tripped" position to isolate incoming power from the converter.

bigben · 02-08-2018, 05:17 PM

Quote:

Originally Posted by Tfryman

OK, do both Air Conditioners run on the generator? Just trying to eliminate the Automatic Transfer Switch and wiring as a possible problem. It is a Thor after all and many have found poor connections at the ATS.

One of the great things about our site is sharing information. Following up discussions with Ted, I went and did some more looking on my coach. Pull off the automatic transfer switch cover and checked the wiring. Sure enough the red inbound terminal from the generator was loose. Tightened it up and all is good - generator is charging very well.

Thanks again to all those on the site but expressly to Ted. Saved me a bunch of grief. Now I just have to figure out the 12 volt no charging issue but at least I have charging going on with the generator. :-) :-) Thanks again to Ted.

Bob Denman · 02-08-2018, 05:23 PM

Glad to hear that it was an easy fix: once you got your nose pointed in the right direction. Congratulations!

**16ACE27** · 02-08-2018, 05:44 PM

1 problem down, 1 to go.

So now that the generator is running the converter to charge the house batteries the next question is: Does it also supply charging voltage to the chassis battery?

You may find that the sense lead from the chassis side has a blown fuse or other problem but that the sense side from the house works fine.

bigben · 02-08-2018, 06:40 PM

Ted - yep charging working GREAT from the on board generator. Voltage through to inverter 13.3 with on board generator running. Turn the generator off and start the coach engine - no charging going on. Sooo - looking at the e-start solenoid side now. Picked up a wiring diagram from the Trobetta website and took some pics of the solenoid.

With the on board generator charging correctly, I can afford to wait for the weather to warm up a bit. When I do, I'll begin isolating the cause - similar to the process with ATS -
starting from the solenoid backward. Should be a little more straight forward - fewer moving parts.

Getting there - 1 issue at a time.

Thanks again Ted.

bigben · 02-08-2018, 06:48 PM

One more thing - Thor Owner Tech support has been great. Daniel Carr (CSR) has provided detail drawings quickly and in addition he answers the phone or places timely call backs.

So HATS OFF to Thor. They've been very helpful. As always though fellow owners have been SPOT ON!!! Thanks Ted.

Oneilkeys · 02-09-2018, 12:19 AM

Quote:

Originally Posted by bigben

Ted - yep charging working GREAT from the on board generator. Voltage through to inverter 13.3 with on board generator running. Turn the generator off and start the coach engine - no charging going on. Sooo - looking at the e-start solenoid side now. Picked up a wiring diagram from the Trobetta website and took some pics of the solenoid.

With the on board generator charging correctly, I can afford to wait for the weather to warm up a bit. When I do, I'll begin isolating the cause - similar to the process with ATS -
starting from the solenoid backward. Should be a little more straight forward - fewer moving parts.

Getting there - 1 issue at a time.

Thanks again Ted.

If u have a Trombetta, you must have something to open/close it like a BIRD or BCC. In my Axis I had a similar issue where the alternator charged the house batteries, but the generator/Shore Power did not charge the chassis battery. It turned that one of the sensing wires to the BIRD was wired incorrectly at the factory. If the BIRD did not sense 13.1v at the house batteries, it would not open the Trombetta to charge the chassis battery. When I hooked the sensing wire to the house batteries everything worked as it should.

bigben · 02-09-2018, 03:32 AM

Oneilkeys - yep, the BIRD and e-Start solenoid wiring check is where my detective work will begin with warmer weather arriving soon. I think the current charging problem might be a result of a blow out we had in late Dec '17. I am going to look for a nicked wire from the automotive alternator to the battery box items - BIRD and e-Solenoid. I have the wiring diagram from Thor that gives me the wire colors and terminal locations. With a multimeter, looking for an open circuit or bad ground should be fairly doable.

Thanks to all you folks again.

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