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Strange chassis battery behavior...

BruceMc
Explorer III
Explorer III
About 3 years ago, I had an incident where the chassis battery discharged for no apparent reason on our '00 Four Winds/Ford E350- no lights were left on, doors closed, ign in lock, etc. The battery was new in 2010.

I recharged the battery, and all was fine until last week when we returned from our 11 day trip. The MH set for a couple days for cleanout, then we headed to town to top off the fuel and propane, and dump wastewater. I parked it, then changed the oil. Upon restarting, it struggled a bit but started. Odd. Restarts after than were fine, so I moved it to a grassy area to wash it in a couple days.
Again, no lights were left on, doors closed, ign in lock, etc.

I washed it two days later, then went to start it to move it to our storage area, and it was dead. A push and hold of the emergency start button for about 5 seconds was all it took, and while holding, it fired right up. I moved the unit to the storage location and put my 10/30/50A charger on 10a for a few days; the starting charge current was about 14 amps. Over then next couple days, it dropped to 1 amp, and the voltage reached 15.5ish.

Over the next few days, I checked it daily to see if it was discharging again - no, it's holding the charge.

However, the resting voltage is 13.5 volts! I've rarely monitored the chassis battery voltage but when I've checked it in the past, I seem to recall it was around 12+ volts. The house batteries (2 GolfCart batteries) rest at 12.4 volts for about a month after a good charge.

After discussing the issue with my son who is a seasoned auto parts store counterperson, he suggests that I may have shorted plates, and the battery may not have much life left. I've never heard of shorted place increasing the voltage - each cell is 2 volts... and if one is shorted, my logic is that it should read 10 to 11 volts.

I know running any battery to zero volts will vastly shorten the life, so I'm prepared to replace it when it finally dies.

Opinions?
2016 Forest River Sunseeker 2250SLEC Chevrolet 6.0L
6 REPLIES 6

dougrainer
Nomad
Nomad
BruceMc wrote:
MXW, I keep a maintenance charger on the chassis battery during storage. Can you suggest why it went flat a couple days after the 11 day 2200 mile trip? I maintain there are no loads on it other than the ECM and radio memory. (Unless this is another ford "issue" - it randomly runs the battery flat in two days... )

I had never seen a battery rest at 13.5 volts, hence my "convoluted" diagnosis. I'd like your technical opinion on what you would do at this point.


A COMMON problem with a Ford chassis is this---The Dimmer wheel or indent for the non existent dome light on some chassis will still engage a relay and the ONLY indication is a dead battery after a few days. A Draw test at the battery will show this draw, but it is difficult to run down if you are not looking for it. Once a Starting battery goes completely dead a few times, it is useless. The plates in chassis type batteries do not function well after a complete dead discharge. Doug

RVs-R-Fun
Explorer
Explorer
Was this ever resolved?


- RVs-R-Fun! ๐Ÿ™‚

BruceMc
Explorer III
Explorer III
MXW, I keep a maintenance charger on the chassis battery during storage. Can you suggest why it went flat a couple days after the 11 day 2200 mile trip? I maintain there are no loads on it other than the ECM and radio memory. (Unless this is another ford "issue" - it randomly runs the battery flat in two days... )

I had never seen a battery rest at 13.5 volts, hence my "convoluted" diagnosis. I'd like your technical opinion on what you would do at this point.
2016 Forest River Sunseeker 2250SLEC Chevrolet 6.0L

OnaQuest
Explorer
Explorer
Chuck_thehammer wrote:
that battery is done. replace it before it quits on the side of the road.
and it could also damage your changing system.

the 13.5 volts resting is a big clue.


Hog Wash

MEXICOWANDERER
Explorer
Explorer
Your diagnostics quite frankly are at best convoluted. Any, even brand new battery of high CCA design that "goes flat" gets damaged. Irreparably so.

Voltage when used by itself is the mere faintest of hints as to the health and potential lifespan of a battery. Sort of like "His temperature is normal, therefore he cannot be having a heart attack".

I really do endorse the idea of constant charge maintenance (temperature corrected float) on BOTH the house and chassis batteries. If you have a brand new rig that throws a hissy-fit if the ECU loses power then you cannot chop power with a switch. But if your rig can handle a power chop, the CHOP IT. What's the use of risking an unwanted, unneeded load? Leaving power connected when it is unnecessary would be like going on vacation in the summer and returning to a surprise 5,000 kWh power bill.

Chuck_thehammer
Explorer
Explorer
that battery is done. replace it before it quits on the side of the road.
and it could also damage your changing system.

the 13.5 volts resting is a big clue.