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Battery questions.....


oscarvan

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Nice new Class A.......

 

Brought it home, plugged it in. 6 Days later tried to start and it was telling me the "Battery Voltage Low".

 

Hit the boost switch and got it going, then charging just fine off the alternator......

 

Control panel told that the house bank charged just fine, all the way to "Float Charge" stage......

 

After we went for a ride put the multi meter on the chassis bank..... 12.6 Not charging.

 

Is the bank supposed to charge when plugged in? Is the isolator that smart?

 

The boost switch is a toggle switch.... Right before I used it it was flashing....

 

Thoughts?

 

(Yes I'm going back to the dealer for something else tomorrow and I will bring it up.... But some peeps here are pretty good so, every bit of the puzzle helps.)

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Is the bank supposed to charge when plugged in? Is the isolator that smart?

 

In most class A's, shore power (converter) will not charge your chassis battery/ies. So.. by "the bank".. if you were referring to the chassis batteries. then no... not usually... only the house bank.

 

There could be a number of issues going on, but from the sounds of it, I would be suspicious of a dead cell or internal short in your chassis battery.. or.. simply a poor cable connection. The alternator sounds like it's working, but to confirm I would check the incoming battery current. If that's in order then it might further confirm a battery issue.

 

If you are not getting sufficient current from the alternator to the chassis battery.. but you ARE to your house bank then you likely have a relay or solenoid issue, but a relay would be the most likely.. and fortunately.. an easy cheap fix since they only run around $3-$5 a pop. A solenoid would run you a bit more.. maybe around $30-$50(?)

 

Probably a really dumb question, but did you happen to check to see if your chassis battery has a lug power disconnect? You didn't mention what make or model you have but some rigs are so equipped for ease of storage.

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I'm not sure if I'm following you but will try my best:

 

"After we went for a ride put the multi meter on the chassis bank..... 12.6 Not charging"

 

On most Motorhomes I've owned when the engine starts either instantly or after a short time delay the engine battery is essentially placed in parallel with the house batteries (via a solid state isolation device or a mechanical isolation relay) so the alternator provides at least some degree of charge (subject to wire size and distance and if mechanical or solid state) to the house batteries while you're driving. Also, if so equipped, an emergency start/jump toggle switch can be manually used to close the isolation relay so if the engine battery is dead the house batteries can be utilized to "jump start" the engine.

 

A full charged battery at rest once stabilized should read around 12.6 volts, but if connected to a good running engine alternator or the Motorhomes battery charger/converter it should rise from at least 13 to 14+ subject to battery state and engine RPM and charger and its algorithm SO 12.6 VOLTS INDICATES SHES NOT CHARGING (if running or plugged in relative to engine or house batteries).

 

Again on Motorhomes I've owned, the coaches Converter/Charger is used to charge the house batteries BUT MOST OFTEN (subject to design and modifications) DOES NOT also charge the engines battery.

.

 

 

"Is the bank supposed to charge when plugged in? Is the isolator that smart?"

 

As above, when plugged in the house batteries are usually being charged but NOT also the engines battery subject to design and mods.

 

 

You may simply have a loose or bad connection or a bad relay or relay wiring or heck even a bad battery which an easy free check and load test will reveal or an alternator problem, hard to say sitting here.

 

John T Still live from Bee Cave Texas

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You either have a bad chassis battery or you have some sort of major battery drain on the chassis battery. Either way, if this is a new RV it should be corrected under warranty. While only a few motorhome manufacturers provide any charging of the chassis battery from the power converter that maintains the coach batteries, a chassis battery should not discharge in 6 days.

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Thank you for the time to answer my questions......

 

Unit is a 2017 Berkshire 38A DP with the Cummins 340.

 

Was at the dealer today to deal with the Atwood piece of doo doo on demand water heater and had a chat with a tech that knows his stuff.......

 

The "low voltage" warning threshold is.....13.4V It comes on when you're going to start the engine (as the alternator is not turning yet) and if it's cold (which it is at the moment) there is a pre heater for the combustion air which draws quite a bit of juice and cycles on and off until the machina gets a little warmer. With it the volt meter does a two step dance and triggers the "low voltage" warning a bunch of times. After 2 minutes things return to their natural state.

 

This is normal. This is NOT mentioned in ANY of the literature. (I have spent countless hours reading the instructions.......) So, non issue other than that it should never even have threatened to be one.

 

According to two long time and multiple Berk owners the chassis batteries are charged after the house bank is charged, as witnessed by the flashing of the "Battery Boost Switch". (That's the one you hit to combine the two banks and have the house bank help start the motor.

 

According to a tech at the dealership the chassis bank is NOT charged.

 

According to the literature, my looking at the system and my multi meter the chassis bank cannot be charged. The inverter/charger goes through a nice three stage process with the house bank and then pretty much takes a nap. There is no way it can be charging the chassis bank though the simple isolation relay without showing activity on the remote monitor.

 

Tomorrow I call the manufacturer......

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Why not read the manuals that came with your Rig? I looked in your signature but did not see anything about a Class A, make, model and year.

 

My Class A, has 3 battery banks. Inverter, Coach & Chassis.

All 3 banks can be changed with generator, shore and alternator.

However owners of my brand failed to read the manuals to understand how the system works.

So, many of us kept answering the same questions over and over again.

Now on the other hand everyone is guessing IMO on how your system works.

But the good news you are going back to the dealer.

By the way, chassis batteries should hold a charge longer then a few days. Longer if you turn on the battery disconnect switch.

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My Class A, has 3 battery banks. Inverter, Coach & Chassis.

All 3 banks can be changed with generator, shore and alternator.

 

That's highly irregular. What is the purpose in having a separate battery bank for just the inverter... and how do you charge it? Your signature only lists a single solar controller and charger... or... you're running duals of each?

 

There ARE rigs that have battery management modules installed, but it's rare and generally an aftermarket user installation. Basically reading charge levels and diverting excess energy between the chassis and coach battery/ies in order and as needed. Generally speaking though it's a one way street from the alternator (chassis battery and then diverted to the coach bank) and a dead end from the charger/converter (charge house bank only and then available for house loads).. either shore or genset power.

 

The house and chassis batteries MUST be isolated at all times... except when engaging the emergency boost to help start a weak chassis battery. Even when a battery management module is installed the respective banks are isolated. It simply allows for excess energy to be more fully utilized when a particular bank might require a "refill".

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Why not read the manuals that came with your Rig? I looked in your signature but did not see anything about a Class A, make, model and year.

 

My Class A, has 3 battery banks. Inverter, Coach & Chassis.

All 3 banks can be changed with generator, shore and alternator.

However owners of my brand failed to read the manuals to understand how the system works.

So, many of us kept answering the same questions over and over again.

Now on the other hand everyone is guessing IMO on how your system works.

But the good news you are going back to the dealer.

By the way, chassis batteries should hold a charge longer then a few days. Longer if you turn on the battery disconnect switch.

 

Really? I DID read the manuals, ALL of them.

 

The Forest RIver "Lets get started" manual, does not address the subject. It very briefly mentions the "battery boost switch" which lets you "start the engine from the house batteries if the chassis batteries have died"....... (It closes the isolation relay momentarily). That's it.

 

The inverter/charger manual does not address multiple banks.

 

The Freight Liner Custom Chassis manual does not address this. (Nor can it as the house/inverter charger setup is strictly an upfitter, ie Forest River, issue.)

 

Your system is not the norm, by a long shot.

 

We do agree that the bank should last longer. But, in fact it did. I found out the warning is normal. I explained that in the post prior to your "talking to". Did you read it?

 

One does not "turn on" a disconnect.

 

Meanwhile I am still getting conflicting information from allegedly knowledgeable sources. Have a call in to FR..... See if I can talk to someone who was involved with the engineering end of this.

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OK, the plot thickens. Two gents on the Berk forum said that indeed the chassis bank charges. You'll see a flashing light in the battery boost switch..... every 20 seconds or so, which means it's happening. I had not seen it yet, and couldn't figure out HOW it would be doing it....

 

But, tonight we were in the Dragonship..... winterizing, reading, decorating and all that. Saw the flash in the switch, ran outside with the multi meter and, by Jove..... 13.8 V on the chassis bank. That is charging.

 

Now I want to know how it do dat..... I see no logical way based on what I've seen in the system.... and (as mentioned before) the books are all silent on the subject.

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Now I want to know how it do dat..... I see no logical way based on what I've seen in the system

There ARE rigs that have battery management modules installed, but it's rare and generally an aftermarket user installation. Basically reading charge levels and diverting excess energy between the chassis and coach battery/ies in order and as needed.

 

More than just a solenoid & relays, a battery manager reads the charge levels of your batteries. When the engine is running.. once the chassis battery is fully charged it will send excess energy to the house bank. When on shore power.. once the house bank is fully charged it will send excess energy to the chassis battery.

 

Good to know the newer Berks have them. I'll file that away. Those that DO have them probably just think it's normal. You're tech at the dealership probably thought he was right because it's NOT common as a standard factory install. Most don't even offer the option and it's SOP that shore connections don't charge the chassis bank. Most battery managers of that type are almost always aftermarket user installations.

 

I would still talk to FR though and get the documentation on it. Many have adjustment controls to set high and low voltage parameters to determine which bank is getting what and when.

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Now I want to know how it do dat..... I see no logical way based on what I've seen in the system.... and (as mentioned before) the books are all silent on the subject.

There are several ways that it could be done and there have been manufacturers who build equipment for that purpose for many years. The Intellitec company has built that type of equipment for some time now and there are probably others. To put it in very simple terms, the equipment monitors the battery charge level, probably via voltage and when it is indicated there is a charge voltage applied. Exactly how they do this will depend upon who built the system that you have but they operate similarly to one of the battery minder products that are available for use on 120V-ac power.

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I thought that in this day all DPs had charging systems like our old 2002, the inverter/charge maintains both sets of batteries when on shore power - house first, then over to the chassis as needed. And it wasn't after market, but that way from the manufacturer.

 

When I throw the disconnect switch, the coach batteries can go three months without a problem. I don't know if they can go longer as we never had tried that, but just start up and go for a ride/recharge after 3 months. If the disconnect switch isn't thrown, then there are a lot of small charges on the chassis system (in our case, the radio/stereo system coach wide is off of the chassis batteries) that can drain it down.

 

Barb

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Nice new Class A.......

 

Brought it home, plugged it in. 6 Days later tried to start and it was telling me the "Battery Voltage Low".

 

Hit the boost switch and got it going, then charging just fine off the alternator......

 

Control panel told that the house bank charged just fine, all the way to "Float Charge" stage......

 

After we went for a ride put the multi meter on the chassis bank..... 12.6 Not charging.

 

Is the bank supposed to charge when plugged in? Is the isolator that smart?

 

The boost switch is a toggle switch.... Right before I used it it was flashing....

 

Thoughts?

 

(Yes I'm going back to the dealer for something else tomorrow and I will bring it up.... But some peeps here are pretty good so, every bit of the puzzle helps.)

Some OEM's have a charge "diverter" that take care of the chassis battery when plugged in or are on solar, but not many. This product http://www.lslproducts.net/TLSPage.html and a larger one from the same company will do that. I used the one that I listed and it worked very well.

 

The literature lists some of the OEM's that actually use their product.

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