No power at key off chassis battery

Oldwirehead · 10-05-2020, 02:19 PM

Problem: I have a 02 Winnebago Adventurer on W22 Workhorse chassis, coach won’t off chassis battery, no power to blower motor or radio. Starts with battery boost and runs fine. Chassis battery show 13.2 volts, ScanGauge shows it charging at 15.6 going down the road. All the fuses are good. Need some help on where to look? This sounds like the P32 problem?

Winterbagoal · 10-05-2020, 03:32 PM

When did you check the chassis battery state of charge, and what type of battery is it? How soon after you shut it off?
How old is the battery, and has it been sitting idle for a while?
Charge it up, pull the cables off, and let it sit for a few hours, then test it for state of charge.

I think you may have a bad battery.
Or, it may be a connectivity issue, bad cable or lug/clamp somewhere.

15.6V from the alternator seems high to me. Like it's trying very hard to charge a a very low or failing battery.

Just guessing.

**creativepart** · 10-05-2020, 05:28 PM

Quote:

Originally Posted by Oldwirehead

Chassis battery show 13.2 volts,

It may "show" 13.2v but that's not the state of charge on your battery. That's simply the charger voltage that's going to the battery.

Turn off the charger. Wait an hour. Put a voltmeter on the battery terminals and you'll see it's dead.

The only question is... can it be saved? It's possible it's too damaged (sulfated) to hold a charge.

To save yourself some money and time - take the battery to an auto parts store to be load tested. Don't want to haul it somewhere? Disconnect it and put a separate charger on it for a couple of days. Then after resting it for an hour after charging put the voltmeter on it. If it shows 12.5 to 12.7v you got lucky.

If money is not the problem you just want it fixed and NOW then replace the battery.

PS. A FULLY charged battery is never 13 point anything volts. Any voltage reading over 12.7 you are seeing either the charger voltage OR a surface charge that shows after charging for up to an hour.

Oldwirehead · 10-07-2020, 08:31 PM

Pull the battery, let it sit all day and got a reading of 12.2 volts with a multimeter. Put it back in and hooked it up. I then heard a low clicking sound, and got a reading on the meter from around 8 volts to 12.3 volts even time it clicks. Suggestions on where to look?

**creativepart** · 10-07-2020, 08:53 PM

Sounds like either a battery that can’t hold a charge or a dead short somewhere in the starting system. The first is the most likely, but the other is a possibility, as well.

PS. 12.2v is 50% discharged you realize.

Oldwirehead · 10-14-2020, 12:59 PM

I'd like to say thank you to the list for there prompt reply to my post, with accurate information to my problem. Replaced the less than 1 year old battery, with a new warranty battery. All is good