What Charges the House & Chassis Batteries When

[16ACE27]

Originally Posted by Oneilkeys

If you stand inside your coach and have someone turn the use/store on and off you should be able to hear the solenoid “thunk” and find it. If you do not hear it, it probably is the problem. When you find it, one of poles with the large wire attached goes to the batteries and the other to the coach. If it in the store position, one of those poles should have approx the same voltage as the batteries and one should show no volts with a volt meter. Carefully, both poles are positive and when the use store is in use, a lot of amps flow thru there. Positive wire to one pole and negative wire to ground from the volt meter. If you’ve never done it, have someone show you the first time. When the use/store is in use, both poles should show the same voltage - if the solenoid is working. If you get no voltage on either pole, the 50 Amp breaker is probably the culprit.

Only true if the coach is not plugged in. If it is plugged in you would have battery voltage on one side and converter voltage on the other side.

[dogday51]

Thanks for the info oneilkeys on the breakers location but no such luck locating them. I do have a my MH plugged into a dedicated 30amp circuit from the house and both the chassis and coach batteries have a full charge and the use/store button is in the "use" position. Still no power to start the engine. Is there a fuse maybe in the fuse block that is preventing my engine from starting? A picture is worth a thousand words and would be helpful in locating the breakers. I have a 2017 Thor Class C Freedom Elite with the Ford V10 engine. Is there anyone in Hot Springs Arkansas that can help me out with my problem. I do not want to have my unit towed (expensive) to Little Rock and then it sit for a month while they go through a diagnostic and repair. HELP

[Jeff H]

Originally Posted by lazinskm

Thanks oneikeys for the Picture. I am the one that started the other thread. I still cannot find this breaker in my Thor class c 28z. My batteries are under the step on a metal tray I would not call it a box. If anybody has an idea where this breaker would be please let me know

lazinskm,

I think Oneilkeys stated that the House Batts breaker is under the steps to the left. On my Thor Vegas 25.3, it's there exactly where he stated it would be. I believe it's on the other side of the battery compartment, which is like an open air area where the house batts are strapped in.

My breaker has a red button on it to test, and the yellow flag pops out, and I have to push it back down to resume current flow through the breaker.

[Oneilkeys]

The breaker to the house batteries under the steps does not have anything to do with starting your engine - unless you are using the emergency start switch. Here are pics of the 100 amp breaker location in my Axis E450. If your engine battery is fully charged and you get no juice to the engine either this or a bad ground are probably your problem.

[lazinskm]

Which side of the engine bay is this? Near the battery? Anybody that has an idea in a class C it is greatly appreciated... Still searching.... I looked everywhere last night, and couldn't find solenoid- told it might be in the engine compartment which does blow my mind....

[lazinskm]

Does anyone know what this box is w the arrows? I couldn’t even see it just took pictures in the rats nest behind my fuse panel. Trying to find this solenoid.

[16ACE27]

That is the solenoid that is controlled by your USE/STORE switch. The small red wire should have a fuse attached to it. There should be battery voltage on one side (the left as I recall) and converter voltage (DC Buss voltage) on the other side.

[Oneilkeys]

Originally Posted by lazinskm

Which side of the engine bay is this? Near the battery? Anybody that has an idea in a class C it is greatly appreciated... Still searching.... I looked everywhere last night, and couldn't find solenoid- told it might be in the engine compartment which does blow my mind....

This is the passenger side of the engine looking into the engine from the front. The battery is behind and to the left of the 100 amp breaker. The breaker needs to be close to the battery - if you have one like this. I had a Ford Class C once, but I don’t remember if it was set up the same way.

[Oneilkeys]

Originally Posted by Tfryman

That is the solenoid that is controlled by your USE/STORE switch. The small red wire should have a fuse attached to it. There should be battery voltage on one side (the left as I recall) and converter voltage (DC Buss voltage) on the other side.

That little red box below the switch on the little red wire is the fuse holder.

[16ACE27]

Originally Posted by Oneilkeys

That little red box below the switch on the little red wire is the fuse holder.

Yep, and the big cable on the battery side should go to the elusive 100 amp breaker.

[Jeff H]

Originally Posted by Oneilkeys

If you stand inside your coach and have someone turn the use/store on and off you should be able to hear the solenoid “thunk” and find it. If you do not hear it, it probably is the problem. When you find it, one of poles with the large wire attached goes to the batteries and the other to the coach. If it in the store position, one of those poles should have approx the same voltage as the batteries and one should show no volts with a volt meter. Carefully, both poles are positive and when the use store is in use, a lot of amps flow thru there. Positive wire to one pole and negative wire to ground from the volt meter. If you’ve never done it, have someone show you the first time. When the use/store is in use, both poles should show the same voltage - if the solenoid is working. If you get no voltage on either pole, the 50 Amp breaker is probably the culprit.

Oneilkeys, If I don't have power to the Coach with ignition key on, engine running, but when I run either the generator or park and have shore power from plugging it. What is my problem source? It doesn't seem like it would be the Battery disconnect switch.

Here's why, listen to this symptom. When I am running the Engine only, I try to push the USE side of the Batt Disconnect switch. It makes the noise near the Breaker relay cabinet where the inverter is, but I don't get any power to the coach. No lights, no water pump, not even a sign of any readings on the monitor panel for battery level or water tank levels.

But when I am on Generator power or Shore power, I have power at every place I should have it and I still push the STORE switch but it does not shut off the Coach Batteries. I manually have to turn everything off. Which I do before I shut down the coach anyway.

It appears the switch doesn't work 2 different ways, one it can't turn anything on with Engine power, and the other is can't shut anything off with Generator or Shore power.

Which in my opinion doesn't seem to be a Battery Cutoff Switch problem. Because wouldn't the problem be the same for a three power sources?

Does my reasoning make any sense? If it does, what would be the issue, the Isolation Relay?

[lazinskm]

Tfryman thanks it is it. Going to replace next week. It was under counter in bathroom under shelf and buried up against front wall.

[Jeff H]

Originally Posted by lazinskm

Does anyone know what this box is w the arrows? I couldn’t even see it just took pictures in the rats nest behind my fuse panel. Trying to find this solenoid. Attachment 9211

Does anyone know where this solenoid is located or how to find it on a Vegas 25.3? I'm assuming behind the fuse panel/Inverter/Beakers station.

[gmc]

Originally Posted by Jeff H

...
But when I am on Generator power or Shore power, I have power at every place I should have it and I still push the STORE switch but it does not shut off the Coach Batteries. I manually have to turn everything off. Which I do before I shut down the coach anyway.

It appears the switch doesn't work 2 different ways, one it can't turn anything on with Engine power, and the other is can't shut anything off with Generator or Shore power.

Which in my opinion doesn't seem to be a Battery Cutoff Switch problem. Because wouldn't the problem be the same for a three power sources?

Does my reasoning make any sense? If it does, what would be the issue, the Isolation Relay?

When you are on generator or shore power - 12v comes from the power converter - so the use/store switch has no effect (on most coaches).
Need to find the solenoid and measure voltage on both side with coach unpowered (unplugged/no genny)
If 12v in and 0v out - with both switch positions - then either switch or solenoid is issue... If no 12v in - then something between batteries and solenoid (100A breaker, batteries themselves, bad connection...)

Originally Posted by Jeff H

Does anyone know where this solenoid is located or how to find it on a Vegas 25.3? I'm assuming behind the fuse panel/Inverter/Beakers station.

Best source for info on Axis/Vegas is the Ed Felker maintained manual...
It's a 'sticky item' in Motorhome Tech Topics
http://www.thorforums.com/forums/f10...nual-4961.html

[Oneilkeys]

Originally Posted by Jeff H

Does anyone know where this solenoid is located or how to find it on a Vegas 25.3? I'm assuming behind the fuse panel/Inverter/Beakers station.

The way the Vegas/Axis is wired, the 12v goes from the engine alternator to the 100 amp breaker in the engine compartment, then to the battery and then to the solenoid (Trombetta/BIM/BCC) and then to the 50/100 amp breaker in the battery box. From here it goes to coach batteries and the UsE/store switch and to the coach. So, if the 100 amp breaker in the engine compartment is open, no power will flow to the engine battery or the solenoid. If power gets to the solenoid, but it does not close, no 12v power will get to the coach batteries. If the 12v from the engine alternator gets past the solenoid and the 100 amp breaker in the battery box is open, the 12v power will not get to the coach batteries or the coach. If that breaker is closed but the Use/store in open, 12v power from the alternator will not flow to the coach batteries or the alternator.

From the shore power or generator side, the 12v power goes to the transfer switch and then to the converter charger which goes to the coach. So you have 12v power. If the use/store switch is in store, the 12v will not flow to the coach batteries or back to the solenoid. If the 12 v power makes it past the use/store but the 100 amp breaker is open, the power will not flow to the coach batteries to charge them or on to the engine batteries. That is why you have 12v power while plugged in or on generator. It is provided thru the transfer switch and converter/charger.

[Oneilkeys]

For Jeff H:

“Here's why, listen to this symptom. When I am running the Engine only, I try to push the USE side of the Batt Disconnect switch. It makes the noise near the Breaker relay cabinet where the inverter is, but I don't get any power to the coach. No lights, no water pump, not even a sign of any readings on the monitor panel for battery level or water tank levels.”

Answering this question, if you are running the engine, the first question - are the coach batteries charging? If they are not, is 12 alternator power getting past the Trombetta/BIM/BCC? To check that see if the two sides of the Trombetta/BIM have the same voltage - somewhere above 13.5 v. If the coach side reads the same voltage as as the coach batteries, that means that 12v power is getting from the cozch batteries to the coach side of the Trombetta/BIM, but the Trombetta is not opening connecting the coach and chassis batteries. It also tells you the two 100 amp breakers are working. If the voltage on both sides of the Trombetta/BIM is the same with the engine running, the Trombetta/BIM is working. If that is the case, now check the voltage at the coach batteries. If it reads the same as at the Trombetta/BIM, the 100 amp breaker is closed and working. If the voltage at the coach batteries reads less than at the Trombetta (below 12.7v) then the 100 amp breaker is open. Either close it or replace it. If the 100 amp breaker is working correctly, but no power is getting to the coach while the engine is running, the UsE/Stire switch is bad. If you hear the thunk when you engage the use/store, then it probably is the 100 amp breaker or a break in the wiring. But it is easy to check using a volt meter.

[rogerddd]

Originally Posted by bevedfelker

There have been a lot of responses on various threads of this forum about what (generator, shore power, and engine alternator) charges what battery (chassis, house) when. In researching technical topics for the Axis/Vegas Owners' Manual I compiled I found information about the Bi-directional Isolator Relay Delay (BIRD). Reading about the BIRD I had the impression that it sensed voltage from the alternator, generator, or shore power and automatically switched charging current to both the chassis battery and house batteries. This left me confused when so many answers to questions on this forum implied that the chassis battery was not charged when running the generator or on shore power.

To try to get a good answer, I sent the following email to Thor Customer Service: "I have a question regarding battery charging -- both chassis and house batteries. I know the chassis battery is charged by the engine alternator. I also know the converter charging circuit charges the house batteries when on shore power or the generator is running. Here are my questions. I have asked several owners and I've gotten more and different answers than I've had questions: 1. Does the alternator provide power to charge the house batteries when driving down the road? 2. If so, dose the USE/STORE switch have to be in USE? 3. Does the converter provide power to charge the chassis battery as well when on shore or generator power? 4. Does my 2015 Vegas 24.1 have a Bi-directional Isolator Relay Delay (BIRD) or is there a BIRD-like circuit in the Battery Control Center (BCC)? 5. Does the BIRD function in both directions; that is, alternator power going to both chassis and house batteries as well as shore/generator power going to both house and chassis batteries? 6. Can I gat a Production drawing of the BCC and also the BIRD (if there is one). Sorry for the myriad questions but how the batteries charge and from where they get their charging power is driving me crazy."

Today I received the following answer from Thor: "Hi Ed, Thank you for contacting Thor Motor Coach. When your coach is going down the road with motor running, it is charging all the batteries – chassis and house. When the coach is sitting plugged into shore power or generator running it is also charging both – chassis and house batteries. For this to happen, motor running or plugged in the USE / STORE switch needs to be in the USE position. I believe the Bird or Bi-directional relay for your coach is under the hood on the driver’s side. But the main part is that yes the system should charge all batteries going both ways. Hope this helps."

When the BIRD senses 13.1 volts for 2.5 minutes on the chassis battery the relay isolator will close sending charging current to the house batteries (alternator providing charge to house batteries. Going the other way when on shore power or running the generator when the BIRD senses 13.1 volts for 2.5 minutes on the house batteries the relay isolator will close sending charging current to the chassis battery (generator or shore power charging the chassis battery).

Given this, the BIRD should keep all batteries charged when the engine is running, when you are running the generator, or when you are on shore power. For this to work for the house batteries, the USE/STORE switch must be in USE. Atch from Intellitec explains BIRD operation.

Sorry for the long explanation, but from the myriad questions regarding battery charging on the forum I thought this would be helpful.

Just so I understand what I think you are saying ( I am new at this) when you mention the USE/STORE switch, am I correct that it is the on/off switch as you enter the motor home?

[rvschneider]

Hi all. New to the forum. I've been trying to educate myself on the RV electrical system. This thread is great!

Problem: My chassis battery was dead the other day, even though I had it plugged in to shore power; Use switch was ON. (Coach battery was fine)

So today I went to my RV and located the Isolator relay under the hood. Took some voltage readings in an attempt to isolate the problem (no pun intended ). Sorry for the long post but here's everything I measured:

1. Engine OFF. Not Plugged in to shore power. 'Use' switch ON. House battery 13.0V. Truck battery 13.0V. Isolator relay not engaged. This is just my baseline so yes I know this step is unnecessary.

2. Engine OFF. Not Plugged in to shore power. Use switch OFF. House battery 13.2v. Truck battery 13.0v . Isolator relay not engaged.

3. Engine OFF. Plugged in to shore power. Use switch ON. House battery 14.0v. Truck battery 13.0v. Isolator relay not engaged.

4. Engine OFF. Plugged in to shore power. Use switch OFF. House battery 13.0v Truck battery 13.0v. Isolator relay not engaged.

---- Started the engine----

5. Engine Running. Not plugged in to shore power. Use switch ON. House battery 15.0v. Truck battery 15.0v. Isolator relay engaged (energized and equal readings on both large posts).

6. Engine Running. Not plugged in to shore power. Use switch OFF. House battery 15.0 . Truck battery 15.0V. Isolator relay engaged

7. Engine Running. Plugged in to shore power. Use switch ON. House battery 15.0V. Truck battery 15.0V. Isolator relay engaged

8. Engine Running. Plugged in to shore power. Use switch OFF. House battery 15.0V. Truck battery 15.0V. Isolator relay engaged

-----

Since the isolator relay actually does function and allows charging from Chassis --> Coach (but not the other direction) my guess is this is a bad BIRD?

Thanks!
_______________________
2014 Thor Four Winds 32'

[rvschneider]

Also, the BIRD that is on my truck doesn't look like the other ones I've seen on this thread. If I need/want to replace it, can I replace it with a newer one? The RV has an Aux Start switch in the cab, but it has never worked since I've owned it (2 years).

_______________________
2014 Thor Four Winds 32'

[Oneilkeys]

Yes. In my Axis it says Use/Store. If it is working correctly, turning it to use will turn on the 12v power from the coach batteries under the steps.
There are various reasons why some owners have problems with the charging system. In my new 2016 Axis Thor has miswired the BIRD so that the wire that sensed the voltage at the coach batteries was not hooked up correctly. That meant that the BIRD never sensed 13.1V at the chassis battery so it never opened the Trombetta to charge the chassis battery on shore power. Other owners have had the solenoid that is hooked to the Use/Store switch fail. That means that no power can get from the coach batteries to the coach. Other owners (me included) have had the 50/100 amp breakers (one in the coach battery box and one in the engine compartment) trip open or fail. That means you either have no 12v power to the coach or none to the engine. And I haven’t even discussed the transfer switch and converter/charger that other owners have had issues with.

If everything is working correctly with the charging system (as in the vast majority of cases) then you have no issues. Because of the complexity of the system, when one of the pieces is installed incorrectly, fails or is tripped by an electrical problem, it can take some time and effort to troubleshoot the problem and come up with a solution.