Is my coach ruining my chassis batteries!!

[CLKimmel]

I’ve had my 2006 Beaver Monterey for about a year and half now and I seem to be having chassis battery issues since I’ve owned it. It came with new batteries but I always had problems starting it. I had it in the shop for some other work and the technician found the batteries were venting and overheating while he was trying to charge them with his charger. He took the batteries over to Interstate and they diagnosed shorted cells and replaced the batteries. Now, just a couple of months later, my batteries are dead and will not take a charge. Is there something that is causing the batteries to fail or is it just bad luck with interstate batteries?

[SuperGewl]

You need to have an electrician check out your MH. It seems that you have something in the MH that is shorted and or at least putting a massive drain on your batteries. When your MH is in storage do you disconnect (open circuit) the batteries? If you don't then you should and if you and the batteries are still being drained there is something that is still drawing power from the batteries. If you don't have the skills to trouble shoot the MH then get it looked at.

[153stars]

Little more info on how long it had been stored before batteries went flat. Many owners have issues battery isolator/combiner to charge chassis batts from house charger.
Do you have a manual battery disconnect for chassis batts. I would not be without one
How are trying /with what kind of charger to recharge chassis batts . Hopefully there not so dead a smart car smart charger refuses to charge them. A shorted cell can just happen not necessarily anything to do with coach.
If you suspect a large drain/draw on batts. Most decent multimeter can test up to 10A draw by putting in between a removed lead and battery. First I would try a 10 amp ATC fuse in between . If it blows, then don't try the meter or it will blow the internal fuse and might be kind of hard to locate new one.

[Country Road]

Originally Posted by CLKimmel

I’ve had my 2006 Beaver Monterey for about a year and half now and I seem to be having chassis battery issues since I’ve owned it. It came with new batteries but I always had problems starting it. I had it in the shop for some other work and the technician found the batteries were venting and overheating while he was trying to charge them with his charger. He took the batteries over to Interstate and they diagnosed shorted cells and replaced the batteries. Now, just a couple of months later, my batteries are dead and will not take a charge. Is there something that is causing the batteries to fail or is it just bad luck with interstate batteries?

Have you been using the coach by driving it over the last 2 months or is the coach not being driven. Just trying to help figure out if the problem is being caused by your coach charging system or perhaps being overcharged thru a fault in the house charging/maintaining system.

You have a tech involved. He should be able to figure this out. I believe that it is not the batteries but something that is overcharging them and burning them up. Good luck.

[Persistent]

There are several possible causes of battery failure. One less likely is that both sets of Interstate batteries were defective.

Troubleshooting:
Is the RV occupied or stored when you try to start it and it failed?
Do you occupy or store plugged into shore power?
How long between time engine is shut down and you try to start again?
Do you switch door 12 volt switch "off"? (Salesman switch)
Do you have two door 12 volt switches? One for house and one for chassis?
What is the make and model of the built in house system charger?

Plugged into shore power:
High charging voltage can destroy lead acid batteries. Long periods of battery terminal voltage above 13.8 can do it. Higher voltage on flooded cells consume more water. Batteries can be "boiled" dry. Measure terminal voltage and monitor water level while parked.

AGM or Maintenance Free batteries will vent and dry out. Water cannot be replaced.

Without shore power or solar power:
Parasitic current drain on the batteries can draw them down flat. The greater the drain, the faster they go flat. Lead acid batteries stored with low state of charge will crystalize sulfate on the plates. Fully recharging 14 to 18 hours after maybe 1 week will probably restore the batteries. After 3 months, they are probably dead for good.

Lead acid batteries must be stored fully charged for 14 to 18 hours for long service life. Measure battery terminal voltage periodically until you know how long your batteries will stay above 12.4 volts. Fully recharge 14 hours before voltage drops below 12.4 volts.

Post more information for better advice.

[Mark_K5LXP]

Interstate makes millions of batteries. It's possible that you ended up with a bad one but odds are much higher it's caused by some way they're being used or stored. I know on my RV there is a parasitic draw on both the house and chassis batteries. Enough that storage for more than a few weeks without supplemental charging or disconnecting them is not optional. Unless you seek out and correct either the charging or discharging problem (or both) you will end up throwing batteries at this until you do. A $10 multimeter and some quality time chasing through the system might reveal a simple cause. A battery disconnect while parked removes a lot of variables. A battery tender is an idle battery's best friend.

Mark B.
Albuquerque, NM

[CLKimmel]

Originally Posted by 153stars

Little more info on how long it had been stored before batteries went flat. Many owners have issues battery isolator/combiner to charge chassis batts from house charger.
Do you have a manual battery disconnect for chassis batts. I would not be without one
How are trying /with what kind of charger to recharge chassis batts . Hopefully there not so dead a smart car smart charger refuses to charge them. A shorted cell can just happen not necessarily anything to do with coach.
If you suspect a large drain/draw on batts. Most decent multimeter can test up to 10A draw by putting in between a removed lead and battery. First I would try a 10 amp ATC fuse in between . If it blows, then don't try the meter or it will blow the internal fuse and might be kind of hard to locate new one.

The chassis batts were fine when I last started it up around the end of November. I had the coach plugged in at that time to keep the batteries charged, but sometime after that it came unplugged and when I plugged it back in and tried to start, they were completely dead. I tried using a battery charger on the chassis batteries, but that wasn't working so I thought it was the charger and I bought another one. It would fault after a few minutes and I disconnected the battery and it started taking a charge, but it only got up to about 11.4v (according to the charger) and faulted after 24 hours. Water levels are good, but one cell was a little low and I topped it off with distilled water before I tried to charge. I'm going to take the batteries and have them tested/replaced and then start troubleshooting to see what might be going on.
Thanks!

[Persistent]

Originally Posted by CLKimmel

The chassis batts were fine when I last started it up around the end of November. I had the coach plugged in at that time to keep the batteries charged, but sometime after that it came unplugged and when I plugged it back in and tried to start, they were completely dead. I tried using a battery charger on the chassis batteries, but that wasn't working so I thought it was the charger and I bought another one. It would fault after a few minutes and I disconnected the battery and it started taking a charge, but it only got up to about 11.4v (according to the charger) and faulted after 24 hours. Water levels are good, but one cell was a little low and I topped it off with distilled water before I tried to charge. I'm going to take the batteries and have them tested/replaced and then start troubleshooting to see what might be going on.
Thanks!

Batteries may have failed. Fully discharged for a month probably left them heavily sulfated. One cell might have shorted. 11.4 volts after 24 hours means they are 2 volts short or one cell short.

[astrnmrtom]

One thing to note is most new battery chargers are "smart" chargers and if a battery is discharged too far, the charger will show a fault, and the charger will refuse to charge the battery. Connecting an older style dumb charger can often get the battery to the point a smart charger will work again.

You could have a issue with the onboard charging system, or parasitic loads. If the onboard charger isn't one that automatically cycles into float mode, it can cause issues especially if you don't regularly monitor the water level.

Another thing that will kill a new battery, is to let it sit discharged in freezing temperatures. Letting a battery sit dead for too long can kill it too.

If your charging system isn't set up to charge the chassis battery - some aren't, you'll need to add one, or install a battery disconnect. I stored my rig in a place without power and installed disconnects. After doing so I never came back to a dead battery.

[153stars]

If you had it plugged in combiner solenoid if equipped may not have been working before it was unplugged.
A pair of GP 31chassis batts may not charge up as fast as a smart charger expects. I've had my Die hard smart charger time out on pair of chassis or 4 house if there down 50% second time usually does the trick. I like to use charge only function on my inverter but it likes to trip garage GFCI as it kicks in sometimes. So I'll give up and use charger. No problem in invert mode but If it was to trip ur get unplugged in invert mode , it won't be long until it runs them down.
If batts are under warranty you should get replaced before it runs out if not bouncing back. Commercial/agricultural gp31s often only 12-18 mo. warranty. but many owners can get 8-10 yrs. out of them.