Thor Vegas 24.1 Battery Control Center

[terencgb1]

Hoping I can get a second opinion, or multiples before i tear into the Battery Conrol Center on my Thor Vegas.
First, we rarely boon-dock so this was the first time in a while that we have had to run on house batteries. And for the record, the house batteries are 9 month old Battle Born Lithiums. The chassis batter is also less than a year old. We pulled up at my in-laws driveway, parked and set up as usual and all seemed well. It was warm so the fans were runing along with the lights. About two hours later the lights flickered a couple of times. Then a couple of hours latter the Vegas went dark! First reaction was to go for the generator. Nothing there even with the emergency start switch. Next was to start the engine. NOTHING THERE EITHER! Sitting in the drivers seat could hear one of the solenoids in the BCC clicking away every few minutes. Luckily we were boon-docking in a drive way (we live a rough life!) and so a couple of extension cables and a few cuss words later, we were back with 15amp shore power, the lights were on and the fans ran. Woo Hoo! we got a goon nights sleep and decided to trouble shoot it in the AM. I woke at about 3am with the big question. Why did the chassis batter die? Its not supposed to be able to feed 12v to the coach - right? Isnt there something that is supposed to disconnect the chassis battery from the coach system but let the coach charge the chassis battery when on shore power? I think that is how its supposed to work so my next thought was ..... BCC or some relay somewhere wasn't wanting us to go to sleep that night!
Next morning I embarked on some diagnostics with my trust meter.
With Shore power ON, Engine OFF volts to chassis battery was 13.4 and volts to house battery 13.4 - conclusion was that the charge in the coach was doing its job and charging both battery sets.
With Shore power off and Engine ON volts to both batteries was a little higher ~13.7 but matched. - Conclusion was that the alternator was charging both battery sets.
With Shore power OFF and Engine OFF the voltage on Chassis battery was at 12.7 so not bad, and the lithiums were at 13.1. - Conclusion, the batteries were OK and not fried.
Next step was to pull out the amp-clamp to see if a parasite load was pulling the chassis battery down. I dropped the clamp on the chassis batter positive lead and saw it was pulling less than .01. I got the same reading on the house battery feed cable. I thought that was maybe a coincidence and so I put some loads on the coach battery by putting the fans and lights on and, as it should, the amp draw went up. I then pulled the clamp off the house battery and put it on the chassis battery. I got the EXACT same load reading. - AHHA - i don't think it is supposed to be like that - is it?. This would explain why the chassis battery died. I think the chassis battery is powering the coach! So. All of this to say, I think the gizmo in the BCC is not isolating the chassis battery when the coach is boon-docking. Before I rip the BCC out and start tinkering with I thought I would run this by the collective wisdom and see if I am on the right track, totally misunderstand how this stuff is supposed to work or missed something so obvious I will be red faced and feeling like the idiot I am. Any thoughts that can help are welcomed! - Thanks

[terencgb1]

Update: After much watching or Youtube, reading and spelunking the web I am now in possession of a little more information. Im sharing here incase it saves somebody else a few hours of searching. Seems the RV Custom Products BCC couples the two batteries together when either of them goes above 13.2V allowing what ever is charging one to flow into the other. It will leave the two batteries coupled together until one or the other drops below 12.6v. Then, when it detects one or the other drop below 12.6V it waits 15 seconds and disconnects them from each other protecting the chassis battery. Based on this I will run some tests in the AM to drop my chassis battery to below 12.6 and see if the cross connect opens the circuit between the two batteries. Of course this doesn't prevent a parasitic load on the chassis battery continuing to pull it down but I should be able to see the load from the main coach drop off. Tune in next week for another exciting episode of "The BCC mystery drama!"

[16ACE27]

What year is your Vegas? Are you sure you have a BCC and not a BIRD or BIM? Many people who switch to Li batteries also switch to a Li-BIM to help prevent these types of issues (as I understand it).

[terencgb1]

ACE! Thank you for weighing in with the thoughts. Im already thinking you are on to something with the Li-BIM. The Vegas is a 2015. Im pretty sure its a BCC. Large metal box located in the compartment under the drivers seat. Now you have me thinking. The Lithiums have a higher resting voltage that could look like a charge, to the BCC, on the house side. That might keep the circuit between the two battery systems bridged. Here i was, thinking it was time to make a cup of tea and go pet the dog and now I am headed down the worm hole of Li-BIMs. Humm how do you retrofit a Li-BIM to a BCC? - The plot thickens

[terencgb1]

Newest Update: Seems Ace was on the money. I have ordered a Li-Bim255 and am now strategizing the best way to put this into the system without completely trashing the BCC. My hope is that I can simply excise that part of the BCC, that opens and closes the bridge between the Chassis and the coach, from the BCC circuits without having to actually tear the box apart. Will keep you posted!

[Chateau_Nomad]

Just want to chime in that we had a recall on our Battery Isolation Module about a month after newly purchased in 2019 (Chateau 24F Ford E-350 chassis).

The scenario you encountered is exactly what was described as a "could happen" issue. It was replaced at the dealer for free under the recall.

Are you sure that metal box under the driver seat isn't part of the airbag collision system? I believe it's called a Restraint Control Module, which detects if the airbags have been deployed.

[JamieGeek]

Originally Posted by Chateau_Nomad

Just want to chime in that we had a recall on our Battery Isolation Module about a month after newly purchased in 2019 (Chateau 24F Ford E-350 chassis).

The scenario you encountered is exactly what was described as a "could happen" issue. It was replaced at the dealer for free under the recall.

Are you sure that metal box under the driver seat isn't part of the airbag collision system? I believe it's called a Restraint Control Module, which detects if the airbags have been deployed.

Yeah a 2015 Vegas will have a BCC in the front outside storage under the driver's seat.

Looks like this, which is not a Restraint Control Module:


For the OP did you pop the cover and see the plug diagram on the other side?


A while ago I did find this .pdf of the circuit board posted on the net somewhere--of course it may not be your version:
RV custom products.pdf
(Breaking the rule here about publishing diagrams as that guy was a bugger to find--its not like you can log into Thor and download that.)

[Chateau_Nomad]

Originally Posted by JamieGeek

Yeah a 2015 Vegas will have a BCC in the front outside storage under the driver's seat.

Looks like this, which is not a Restraint Control Module:
Attachment 32035

For the OP did you pop the cover and see the plug diagram on the other side?
Attachment 32036

A while ago I did find this .pdf of the circuit board posted on the net somewhere--of course it may not be your version:
Attachment 32037
(Breaking the rule here about publishing diagrams as that guy was a bugger to find--its not like you can log into Thor and download that.)

Oops... I misread the part about "IN THE COMPARTMENT under the driver's seat". The RCM is bolted to the floor directly under the driver's seat. SORRY!

[terencgb1]

Originally Posted by JamieGeek

Yeah a 2015 Vegas will have a BCC in the front outside storage under the driver's seat.

Jamie. Thanks for a huge support post and great information. Thanks to all who have posted help. This has been super helpful. And so without further a do... Here is an update.

I have confirmed I have the RV Custom Products Battery Control Center. My particular model is a TH-1020, Rev B1 with a part number FW221.

I have ordered and received a Li-Bim 225 and plan to install it. The high level plan is to use the Li-Bim to replace the solenoid that is in the BCC that bridges the chassis and house batteries. Here is the plan:


On the outside of the BCC are the battery connectors.
1. Jumper a short 2AWG cable from the chassis battery connector on the BCC to the Chassis lug on the Li-Bim
2. Jumper a short 2AWG cable from the house battery connector on the BCC to the house lug in the Li-bim.
3. Connect the ground terminal on the Li-bim to the ground terminal on the BCC.
4. inside the Li-Bim. Disconnect / cut the connectors that go to the solenoid inside the BCC. (BTW Wayne Polcin has a great video on youtube that shows him taking the BCC apart, posted in 2020). This will take the solenoid out of the game but leave the bus bars intact for everything else.
5. On the board, cut the pin 1 cable on Connector P1 and run that to the Bi-Lim "signal" terminal this will be the emergency start button that will bridge the two battery systems.
6. Add a cable into the P3 connector at position 2, currently empty as I dont have motorized steps and re-fuse that at 3 amps which is more than enough to drive the Li-Bim and less than the wire rating.

Hopefully this will all be complete this week and Ill post the results and maybe even a few pictures. The state of the terminals on eth outside the BCC is not pretty and they are also pretty exposed in the little slot back there if something was to fall on them so I may just do a little additional work tidying up Thors installations (an ongoing task!) and make the whole thing a little less exposed.

Thanks again for all your help. Having the brain trust of this group at our disposal is a gift!
5.

[Nautica2017]

Hi, newbie owning 2017 Thor Vegas, parking at home with home power but chassis battery die. Coach battery is ok. Not sure what is the cause that kill the chassis battery. After charged/jump chassis battery, RV engine run again. Keep on happens every time I park for coupe days or more.
Any suggestions would be greatful.

Thanks

[terencgb1]

Originally Posted by Nautica2017

Hi, newbie owning 2017 Thor Vegas, parking at home with home power but chassis battery die. Coach battery is ok. Not sure what is the cause that kill the chassis battery. After charged/jump chassis battery, RV engine run again. Keep on happens every time I park for coupe days or more.
Any suggestions would be greatful.

Thanks

Welcome to the electrical woes :-)

As I started the tread I'll see what I can offer and apology if this is basic stuff.

1. Possible bad chassis battery. You can do a basic test with a voltmeter or drive to an autoparts store who should be able to test it for you.
2. See if the coach is charging the chassis battery. With shore power off, put a volt meter on the chassis battery. Get the reading and hopefully it is > 12v. Plug in the coach to the shore power and the wait a few minutes for everything to 'get on shore power'. Your volts at the chassis battery should have gone up to >13 if you are getting a charge from the onboard house charger.

If you are getting a chassis battery charge on shore power and your battery is good its a deeper problem of Amp Eaters draining your charge but start with the basics and it wil tell you a lot. If it';s an original battery .. might be time for a new one.

[Nautica2017]

Thanks fo the reply. Chassis battery January 2019. Will hav wit test tomorrow at auto parts store. Thanks again

[mcr1010]

As have a good many of us on the forum; installed a knife disconnect on top of the negative post of the chassis battery instead of trying to chase down the parasitic draws that plague RV's. I have one on the house batteries also. That way you know there is nothing pulling your batteries down.
Good luck

[Axis25.2]

Originally Posted by JamieGeek

Yeah a 2015 Vegas will have a BCC in the front outside storage under the driver's seat.

Looks like this, which is not a Restraint Control Module:
Attachment 32035

For the OP did you pop the cover and see the plug diagram on the other side?
Attachment 32036

A while ago I did find this .pdf of the circuit board posted on the net somewhere--of course it may not be your version:
Attachment 32037
(Breaking the rule here about publishing diagrams as that guy was a bugger to find--its not like you can log into Thor and download that.)

You can't publish diagrams???

[16ACE27]

Originally Posted by Axis25.2

You can't publish diagrams???

There's no "rule" against publishing diagrams. What you can't post are Thor's copyrighted diagrams. That's not a Forum rule, that's copyright law.

[CapnJeff]

thanks for the tip about the knife disconnect but why the negative side? couldn't there still be a parasitic draw, especially if there's a wire grounding out somewhere?

[galOnTheGo]

I agree, there exists a disconnect on the neg, and a big fuse on the positive with a mechanical switch on the fuse. there have been times when I disconnect the neg and have returned a week later to find battery drained. I found disconnecting the positive via the mechanical switch prevents the unwanted drain. I also continue to disconnect the neg.

added details - I have a renogy dc to dc charger that causes the drain problem, have contacted renogy to make them aware of the problem. when I disconnect the negative, the dc to dc turns itself on! this drains the battery. renogy acknowledges this "problem". thus, I have learned to disconnect the positive via the fuse mechanical switch as well. my problem solved. additionally, when the dc to dc drains the battery, it faults, will not function again. but don't despair, the fault can be cleared by disconnecting ALL the cables from it. I learned this all the hard way. we really like our dc to dc charger, despite it's fault.

and, ditto on the lithium BIM. I learned that the hard way as well. it was a very easy change for us, once I figured out what the problem was. a swap out of the existing BIM found under the drivers side hood, front.

[16ACE27]

Originally Posted by CapnJeff

thanks for the tip about the knife disconnect but why the negative side? couldn't there still be a parasitic draw, especially if there's a wire grounding out somewhere?

The negative side is for safety. With the negative side open you could not accidently short the positive side to ground. Witha a knife switch on the positive side you can easily still cross a wrench from the positive battery post to the metal chassis and short the battery/

With the knife switch open in either location no, none, nada, zip current can flow through the battery, so no parasitic draw is possible.

[CapnJeff]

Originally Posted by 16ACE27

The negative side is for safety. With the negative side open you could not accidently short the positive side to ground. Witha a knife switch on the positive side you can easily still cross a wrench from the positive battery post to the metal chassis and short the battery/

With the knife switch open in either location no, none, nada, zip current can flow through the battery, so no parasitic draw is possible.

Are you saying you would put a knife disconnect on both the negative and positive posts?

[CapnJeff]

Originally Posted by galOnTheGo

I agree, there exists a disconnect on the neg, and a big fuse on the positive with a mechanical switch on the fuse. there have been times when I disconnect the neg and have returned a week later to find battery drained. I found disconnecting the positive via the mechanical switch prevents the unwanted drain. I also continue to disconnect the neg.

added details - I have a renogy dc to dc charger that causes the drain problem, have contacted renogy to make them aware of the problem. when I disconnect the negative, the dc to dc turns itself on! this drains the battery. renogy acknowledges this "problem". thus, I have learned to disconnect the positive via the fuse mechanical switch as well. my problem solved. additionally, when the dc to dc drains the battery, it faults, will not function again. but don't despair, the fault can be cleared by disconnecting ALL the cables from it. I learned this all the hard way. we really like our dc to dc charger, despite it's fault.

and, ditto on the lithium BIM. I learned that the hard way as well. it was a very easy change for us, once I figured out what the problem was. a swap out of the existing BIM found under the drivers side hood, front.

Thanks Gal. Sounds like a disconnect is a lot easier than trying to track down the problem with the battery manager