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Old 06-16-2019, 05:33 PM   #1
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Chassis not charging coach batteries, need some help diagnosing

Hello, I have a 2007 Itasca Sunova 35J

The Coach batteries are 1.5 years old, and have only used the coach about four trips.

The deep cell batteries after charging with a charger read out as only 8.8 on the multimeter, while the chassis battery reads a full 13.

When the chassis is running, I still get the same low reading on the house units, but slightly higher on the chassis battery.

Shouldn’t I be getting a charging flow from the chassis lines on the coach batteries while the truck is running?

I’m just not sure if I should buy new batteries, or is there another issue with the charging system.

My next step is to check the battery fluid level, and try to charge each one independently with a charger.

Any thoughts on how to diagnose the chassis charging system for coach batteries?

Any help would be appreciated.

Thanks

Jon
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Old 06-16-2019, 05:45 PM   #2
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Quote:
Originally Posted by jdmalibu View Post
Hello, I have a 2007 Itasca Sunova 35J

The Coach batteries are 1.5 years old, and have only used the coach about four trips.

The deep cell batteries after charging with a charger read out as only 8.8 on the multimeter, while the chassis battery reads a full 13.

When the chassis is running, I still get the same low reading on the house units, but slightly higher on the chassis battery.

Shouldn’t I be getting a charging flow from the chassis lines on the coach batteries while the truck is running?

I’m just not sure if I should buy new batteries, or is there another issue with the charging system.

My next step is to check the battery fluid level, and try to charge each one independently with a charger.

Any thoughts on how to diagnose the chassis charging system for coach batteries?

Any help would be appreciated.

Thanks

Jon
A reading of 8.8 volts means the battery is probably toast. First check the fluid level and top up with distilled water. Then charge the batteries. Check the voltage with a meter and check the cells with a hydrometer. You may have one or more dead cells. If you are lucky, and the cells are good, the battery may still hold a charge. But likely they won't.
When you have charged batteries, check the voltage before and after starting the engine. If you don't get a higher reading with the engine running, most likely the isolator solinoid needs to be replaced.
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Old 06-16-2019, 08:21 PM   #3
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Ditto on battery status.
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Old 06-16-2019, 09:24 PM   #4
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I had an instance where my house batteries were not charging on a trip. I found a blown fuse, replaced it and all was well.
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Old 06-17-2019, 10:43 AM   #5
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Quote:
Originally Posted by jdmalibu View Post
Hello, I have a 2007 Itasca Sunova 35J

The Coach batteries are 1.5 years old, and have only used the coach about four trips.

The deep cell batteries after charging with a charger read out as only 8.8 on the multimeter, while the chassis battery reads a full 13.

When the chassis is running, I still get the same low reading on the house units, but slightly higher on the chassis battery.

Shouldn’t I be getting a charging flow from the chassis lines on the coach batteries while the truck is running?

I’m just not sure if I should buy new batteries, or is there another issue with the charging system.

My next step is to check the battery fluid level, and try to charge each one independently with a charger.

Any thoughts on how to diagnose the chassis charging system for coach batteries?

Any help would be appreciated.

Thanks

Jon
Ok Jon,
Let's take this one step at a time. First, the VERY FIRST thing I try and tell folks is to LEARN THEIR COACH. And that means, just how things work, especially in the battery department. About 99.999999999999999999999999999999999999% of the RVs made in the last century or two, do have both sets of batteries, chassis and house, charge while the main engine is running. Different coach builders do it different ways. Now, your '07 Itasca "could" be different than our '04 Itasca. And, ours is a diesel unit whereas, yours might be a gas unit as I'm not all that familiar with the Sunova model.

But, I'll give you a short description of how ours works and maybe, you can check to see if your Itasca is designed similarly.

First, on our dash, is a switch or toggle, that is labeled as "Auxiliary Battery Boost". That switch, or toggle, when pushed, sends a signal to a very large solenoid located SOMEPLACE on your coach. It does not have to be near the batteries. That solenoid has TWO duties. The first duty is to link the house batteries to the chassis batteries if, the chassis batteries are too low in voltage and amperage to crank the main engine. By linking the two sets of batteries, you now have more cranking power available.

But, once you let go of that toggle, that solenoid is disengaged, separating the house and chassis batteries. OK, that's one duty of that solenoid.

The second duty of that solenoid is this. When your engine starts, via an ignition wire that leads to that solenoid, that same solenoid is then engaged, and, the charging from the alternator that is sent to the CHASSIS batteries, is also sent to the HOUSE batteries. Now, you have the engine alternator charging BOTH sets of batteries.

Ok, that's how the basic Winnebago/Itasca system worked, at least in mine, and quite possibly your era coach. This is yet to be determined by YOU and your coach. I do not guarantee that what I'm telling you is accurate for your coach, only ours. But, it's worth investigating for your personal knowledge.

Now, THAT may be how your charging system works, when the engine is running. As for shore power, and charging both house and chassis batteries, again, ours may be slightly different than yours and, it may be MAJORLY different if yours is a gasser which, I think it is. If yours is a gasser, you more than likely have a "Converter" that handles the supply of 12V to your coach and house batteries. As for a converter that also charges the chassis batteries while on shore power, yes, they exist but, not having one for a long, long time, I cannot really explain how the converter is tied into the chassis batteries for charging.

Now, as for your battery voltage. Well, again, you must determine if your charging system(s) are working correctly, BEFORE you worry about the battery readings. It doesn't do any good to buy a bunch of new batteries, if your charging system(s) are not working correctly. Once you've determined your charging system(s) are working as designed and correctly, THEN go after batteries and or condition.

Your engines alternator should be putting out a fairly steady 13.8-14.5V DC for the most part. You should be getting that kind of voltage to your battery posts. And therefore, if your batteries are in good shape with no defects, you'll have that kind of available voltage from them. Your "converter" should be putting out the same kind and amount of DC voltage to your house batteries and potentially chassis batteries. So, that's kind-of how those systems work. Again, yours could be slightly different. I don't like to ASSUME that all, even the same brand of coach, works the same exact way. Good luck.
Scott
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Old 06-17-2019, 11:01 AM   #6
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I also had this exact same problem... turned out the inverter which has an ordinary household electrical plug on it (located in the rat's nest known as "under the bed" in our Thor) had become unplugged. Sometimes it's the simple things. Good luck!
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Old 06-17-2019, 11:14 AM   #7
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Hi ! Welcome to IRV2! We're sure glad you joined the gang!

I can't add to what others have suggested! Have fun and keep her between the ditches!

Good luck, happy trails, and God bless!
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Old 06-17-2019, 11:57 AM   #8
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Quote:
Originally Posted by jdmalibu View Post
The deep cell batteries after charging with a charger
1. Was this measurement made with the charger connected/powered?

2. What charger is this? The converter in the RV or a separate/stand alone unit?

3. How long were the batteries allowed to charge?

8.8V is "dead". The only way they'd stay at 8V with a charger connected is if the charger won't start with a voltage that low (most don't care or want to see just a couple volts), or the charger isn't putting anything out.

Quote:
Shouldn’t I be getting a charging flow from the chassis lines on the coach batteries while the truck is running?
Yes. The $1M question is why a separate charger isn't charging them.

I would be verifying connections and system function before I went out and bought new batteries.

Quote:
My next step is to check the battery fluid level, and try to charge each one independently with a charger.
If this is your next step, what did you do before when you said they didn't charge with a charger?

Mark B.
Albuquerque, NM
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Old 06-17-2019, 01:39 PM   #9
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Help , my brother in law just got an 07 Bounder . Needed house and Chasis batteries . We put them in all went well . However, we don’t have power inside on everything . Did we pop a breaker somewhere? And where is the battery disconnect switch? We can’t find it . Please help .
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Old 06-18-2019, 07:31 AM   #10
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Quote:
Originally Posted by FIRE UP View Post
Ok Jon,
Let's take this one step at a time. First, the VERY FIRST thing I try and tell folks is to LEARN THEIR COACH. And that means, just how things work, especially in the battery department. About 99.999999999999999999999999999999999999% of the RVs made in the last century or two, do have both sets of batteries, chassis and house, charge while the main engine is running. Different coach builders do it different ways. Now, your '07 Itasca "could" be different than our '04 Itasca. And, ours is a diesel unit whereas, yours might be a gas unit as I'm not all that familiar with the Sunova model.

But, I'll give you a short description of how ours works and maybe, you can check to see if your Itasca is designed similarly.

First, on our dash, is a switch or toggle, that is labeled as "Auxiliary Battery Boost". That switch, or toggle, when pushed, sends a signal to a very large solenoid located SOMEPLACE on your coach. It does not have to be near the batteries. That solenoid has TWO duties. The first duty is to link the house batteries to the chassis batteries if, the chassis batteries are too low in voltage and amperage to crank the main engine. By linking the two sets of batteries, you now have more cranking power available.

But, once you let go of that toggle, that solenoid is disengaged, separating the house and chassis batteries. OK, that's one duty of that solenoid.

The second duty of that solenoid is this. When your engine starts, via an ignition wire that leads to that solenoid, that same solenoid is then engaged, and, the charging from the alternator that is sent to the CHASSIS batteries, is also sent to the HOUSE batteries. Now, you have the engine alternator charging BOTH sets of batteries.

Ok, that's how the basic Winnebago/Itasca system worked, at least in mine, and quite possibly your era coach. This is yet to be determined by YOU and your coach. I do not guarantee that what I'm telling you is accurate for your coach, only ours. But, it's worth investigating for your personal knowledge.

Now, THAT may be how your charging system works, when the engine is running. As for shore power, and charging both house and chassis batteries, again, ours may be slightly different than yours and, it may be MAJORLY different if yours is a gasser which, I think it is. If yours is a gasser, you more than likely have a "Converter" that handles the supply of 12V to your coach and house batteries. As for a converter that also charges the chassis batteries while on shore power, yes, they exist but, not having one for a long, long time, I cannot really explain how the converter is tied into the chassis batteries for charging.

Now, as for your battery voltage. Well, again, you must determine if your charging system(s) are working correctly, BEFORE you worry about the battery readings. It doesn't do any good to buy a bunch of new batteries, if your charging system(s) are not working correctly. Once you've determined your charging system(s) are working as designed and correctly, THEN go after batteries and or condition.

Your engines alternator should be putting out a fairly steady 13.8-14.5V DC for the most part. You should be getting that kind of voltage to your battery posts. And therefore, if your batteries are in good shape with no defects, you'll have that kind of available voltage from them. Your "converter" should be putting out the same kind and amount of DC voltage to your house batteries and potentially chassis batteries. So, that's kind-of how those systems work. Again, yours could be slightly different. I don't like to ASSUME that all, even the same brand of coach, works the same exact way. Good luck.
Scott
This is a great explanation of the system, yes my coach is set up just like yours. Last year I found my converter charger had a blown auto fuse on the rear, that issue was that I was not getting the coach batteries charged while on shore power.

I have a feeling that the chassis charging has never worked since I’ve owned it. Just about 1 year.

Currently I removed my coach batteries, filled them with distilled water to the correct level, and they are sitting for 24 hours. This afternoon I’m going to try to charge them again, then check the fluids with the hydrometer again...they failed previously before I added water.

I priced out 2 replacement batteries for $90 each. I’m sure my batteries are spent, but just want to make sure I’m not throwing money away.

Tonight I should be able to confirm with fully charged coach batteries if they are getting a charge from the chassis while running.
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Old 06-18-2019, 07:42 AM   #11
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Quote:
Originally Posted by Mark_K5LXP View Post
1. Was this measurement made with the charger connected/powered?

2. What charger is this? The converter in the RV or a separate/stand alone unit?

3. How long were the batteries allowed to charge?

8.8V is "dead". The only way they'd stay at 8V with a charger connected is if the charger won't start with a voltage that low (most don't care or want to see just a couple volts), or the charger isn't putting anything out.

Yes. The $1M question is why a separate charger isn't charging them.

I would be verifying connections and system function before I went out and bought new batteries.

If this is your next step, what did you do before when you said they didn't charge with a charger?

Mark B.
Albuquerque, NM
The measurement was made with the chassis off and no shore power, and after I charged them with a Schumer stand alone charger, I charged them both at once.....batteries were connected.

I have since removed the batteries, tested with hydrometer..fail, then added distilled water. I read to wait 24 hours for the battery fluids to mix, so once done I’m going to put each battery on the charger again separately and then test fluids and volts one last time. Probably overkill but Because the batteries are less than 2 years old, I want to make sure it’s not because of the battery maintenance.

I really appreciate your assistance, hopefully I’ll have moved this further along by days end.
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Old 06-18-2019, 07:43 AM   #12
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Originally Posted by jdmalibu View Post
The measurement was made with the chassis off and no shore power, and after I charged them with a Schumer stand alone charger, I charged them both at once.....batteries were connected.

I have since removed the batteries, tested with hydrometer..fail, then added distilled water. I read to wait 24 hours for the battery fluids to mix, so once done I’m going to put each battery on the charger again separately and then test fluids and volts one last time. Probably overkill but Because the batteries are less than 2 years old, I want to make sure it’s not because of the battery maintenance.

I really appreciate your assistance, hopefully I’ll have moved this further along by days end.
Batteries charged overnight, the Schumer unit shut itself off....at least 5-6 hours maybe more.
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Old 06-18-2019, 11:12 AM   #13
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"jdmalibu"....Most likely, the "B.I.R.D." on your coach is bad. It's a by directional charging device. When your ENGINE is running, the coach's alternator looks at your two sets of batteries, chassis and house. It initially looks at the chassis batteries since that's it's primary function. Once it sees that they are charged, it then looks at the house batteries. If they're lower than the chassis, it directs it's charging to them via some type/brand of bidirectional charger. This has been a standard function on motor homes for years.

When you're parked and on SHORE power, your converter charger or converter/inverter charger charges your house batteries. When they're fully charged, it is also suppose to look at your chassis batteries and charge them. (It doesn't sound like you have an issue with this.) It wasn't until about your year model that this became a standard feature. My 2005 Monaco Diplomat required that I add an additional device for the converter/inverter charger to charge my chassis batteries when on shore power.

At a minimum, your house batteries are junk. You'll never find out what's wrong with your system until you install fully charged batteries. Just installing the new batteries may solve all your issues. You may have had a bad house battery since you bought it and was dragging the system down.

Once you get new batteries installed, you need to see if they're getting charged while the engine is running. Keep in mind that the chassis battery needs to be fully charged (engine has been running for awhile) and then check to see if you're getting from 13.8 to 14.2 on the house batteries. You may need to turn some things on inside the coach to drag the house batteries down enough for the alternator to see they need charging. If you never see the above voltage, you have an issue with the bidirectional unit.
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Old 06-18-2019, 12:05 PM   #14
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Quote:
Originally Posted by jdmalibu View Post
Batteries charged overnight, the Schumer unit shut itself off....at least 5-6 hours maybe more.
This is suspect in itself - that's not long enough to do a charge cycle on a dead but otherwise good battery. You didn't say what kind of batteries or charger you have but to replace upwards of a couple hundred Ah takes a lot longer than that at max rated charge current. It would be useful to monitor current and voltage and see if they're actually charging and the batteries are successfully entering absorption phase. A flooded battery must reach and be held at an absorption voltage long enough for gassing to start and agitate the electrolyte to reach a 100% charge. So before I'd pass judgement on the batteries I'd make sure the external charger is bringing them up properly.

Mark B.
Albuquerque, NM
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