Coach Batteries Not Charging While Driving

cupchurch · 06-30-2016, 09:15 PM

A week ago, after driving for about 2.5 hours my xantrex started alarming indicating low voltage (codes 001 then 002). Voltage dropped below 12v. Not sure why charging would stop after indicating a charge when I started my trip back home after dry-camping for a week.
Audible alarm was 5 long beeps followed by about a minute of silence. This went on for about an hour. Then it went to several short audible beeps without stopping until I plugged into shore power at home. I did not have my Genset turned on while driving.
Just started the engine after unplugging shore power and voltage goes from about 13.2 (shore power) to over 14v with engine running. I called Thor Tech and they indicated something is not right. I do have an appointment with a nearby shop for some other warranty checks, but wanted to know if anyone else may have experienced the same. Thank you

tenbear · 07-01-2016, 11:49 AM

"Just started the engine after unplugging shore power and voltage goes from about 13.2 (shore power) to over 14v with engine running."

If this is the voltage at the house battery, it indicates the battery is being charged.

cupchurch · 07-01-2016, 02:02 PM

I agree. For some reason the charging stops after a couple of hours of driving. I winter in Az and have made 1 round trip in this coach. I have my genset on during these trips to keep the frig on (frig only runs on battery or power. No LP option in this rig) and kick the AC on if the coach gets too hot. I have a few dogs and a cat riding along:-) I have over 130 hours on this generator and other than my week long camping last week have only camp a few weekends.

Oneilkeys · 07-01-2016, 02:59 PM

You might check and see if the Trombetta is closing for some reason after the engine heats up. The Trombetta is supposed to stay open to charge the house batteries after the engine starts. Upon engine start, the Trombetta is closed and shortly thereafter the BIRD opens the Trombetta and it is supposed to keep it open until after the engine is shut off. It sound like the BIRD may be opening the Trombetta charging your house batteries and then for some reason the Trombetta is closing which would result in the house batteries no longer being charged. The way you could check this is to measure the voltage at both terminals of the Trombetta before you start the RV. They should read differently, the same as the charges on the house and chassis batteries. Then when the house batteries show that they are being charged by the engine (after the Trombetta opens) check the voltage at the terminals again with the engine running. The voltage should be the same at both terminals indicating the Trombetta is open. After the house batteries stop being charged by the engine, with the engine still running check the voltage at the Trombetta terminals again. I bet you will find the voltage different which will indicate that you have a bad Trombetta or a bad BIRD - which is not keeping the Trombetta open.

cupchurch · 07-01-2016, 06:22 PM

Thank you for your post. Will this unit be near the coach batteries (under the steps). Or, near one of the two chassis batteries under the hood?

Oneilkeys · 07-01-2016, 06:59 PM

In the Axis/Vegas it is located under the hood at the front of the engine on the driver's side. See the Vegas/Axis manual from Ed Felker for a full discussion of the workings of the Trombetta/BIRD or search oneilkeys and Trombetta for my posts in this issue. See attached photo for the Trombetta/BIRD in my Axis. The Trombetta (nothing more than a solenoid) is the one with the two large red wires leading to it. Those are the connections to the house and coach batteries. To the right of the Trombetta is the BIRD which controls the opening and closing of the Trombetta.

Oneilkeys · 07-01-2016, 07:06 PM

This was one of Ed's excellent posts on this issue earlier this year.

cupchurch · 07-01-2016, 07:23 PM

Very informative and helpful. Thor replaced my batteries within a few months of my purchase since the Dealer did not maintain them properly. Batteries should be good. Also, found out the hard way about the USE / Store switch needing to be in Use when plugged in to Shore power. I will be doing some troubleshooting this weekend. Thank you. Will let you know.

Oneilkeys · 07-01-2016, 07:35 PM

Good luck. My issue was that the BIRD was wired incorrectly at the factory. But since you systems works when you turn it on, your problem is not the same as mine. For what it is worth, in talking with the people at Trombetta and the company that makes the BIRD, I got the strong impression that the Trombetta almost never fails. Since yours is an intermittent failure however, it seems possible that it could be overheating somehow which causes it to open. A more likely option is that for some reason the BIRD is closing the Trombetta when it should be keeping it open. Should be an interesting weekend. Hope you find it.

scrubjaysnest · 07-02-2016, 03:37 PM

Way to complicated, if Thor had used a Shure power dual battery system it would be a lot better. That is what I have always used with only one failure since I installed the first one in a 1973 CJ. That failed in 2010; the current one is starting it's 6th year.

cupchurch · 07-30-2016, 11:11 PM

Just wanted to let you know the Bi-Directional Isolator Relay Delay (BIRD) was replaced. I took the RV to a Thor Service Dealer since I had other warranty things to be done. I printed out the Posts related and the Service Manual for the BIRD. Showed it to the Service Mgr when I dropped it off. Also, left in the RV for the techs to see. I think it helped as the problem was not one that was always evident. Thank you.

Oneilkeys · 08-02-2016, 02:39 AM

Quote:

Originally Posted by cupchurch

Just wanted to let you know the Bi-Directional Isolator Relay Delay (BIRD) was replaced. I took the RV to a Thor Service Dealer since I had other warranty things to be done. I printed out the Posts related and the Service Manual for the BIRD. Showed it to the Service Mgr when I dropped it off. Also, left in the RV for the techs to see. I think it helped as the problem was not one that was always evident. Thank you.

Glad to see you got it fixed. Good luck with your RV. Hope u have no further problems.

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