I drove my MH today after it had been parked for three weeks plugged into 20 amp power. I drove 15 minutes then stopped for lunch. I checked the voltage before leaving the MH. The voltage display showed 12.5 volts. The only things on at the time were the residential fridge, the inverter and the battery charger. I came back to the MH in one hour and voltage showed 10.7 volts. The inverter had cut off. I cranked the generator and the charger started bulk charging. After about one minute, it switched to absorb charging. Does that sound like an inverter problem or are the batteries shot? I have four six volt batteries that are three years old.

Something is screwy.What do you mean the 'battery charger' was on? Do you have an inverter/charger? Why did the inverter cut off.. low voltage? What sort of meter tells you the generator went to absorb charging? Is there enough water in your batteries?Even at 3 years old, if the batteries aren't maintained or are over-charged they will be shot. That's my first suspect.

I think I could answer most of oldman's questions and I don't think the answers mean much. An important question however is how much water is in your batteries. If they are low it could mean that they are being overcharged and boiling off the electrolyte. I think you may have one or more bad batteries and would have them load tested as a group and individually. If the converter has a pendant, it would show the bulk charge but to drop from 12.5 to 10.7 volts in just one hour is weird and sounds a lot like a bad cell in one of the batteries. Here is the sketchy part, with the batteries being only 36 months old and normally they are rated for 72 months, do you need to replace all four? We used to replace bad cells in our 512 cell battery but only once did we replace all the cells. Then again we had to cut holes in the hull to replace them all.Making sure all the connections are good after the individual load test is a good idea, if they need water add some before driving over to have them tested. You need to do all those normal things we all forget to do or put off on occasion sometime during this trouble shooting procedure.Sorry about the curt reply to you but he sounded like he knew a lot about what he wrote.

I was incorrect in stating that the charger was on. Yes, I do have an inverter/charger. When on shore power, or generator, the inverter/charger display in the MH shows if the charger is bulk charging, absorb charging or float charging. Normally, the bulk charging phase last much longer one, two, or even 10 minutes, unless I have a problem. What I do not know is if my problem is the inverter or bad batteries. I did top off the water in the batteries three weeks ago.

Get a Hydrometer and check each cell, you may have a bad cell. At 12.5 they are not fully charged and to drop to 10.7 they are dead. Mine 4 batteries flot at 13.6 same with my starting battery 13.6 I would think your inverter is ok mine is on inverter all the time because of the RR frig.JR

Will get a hydrometer tomorrow and check the batteries. If the batteries are bad, I am looking at buying a new set at SAMs. Can anyone comment on Energizer 6 Volt Premium Batteries - Group Size GC2 for $112.68 each?

Battery Problems | Good Sam Community

12 Replies

Pass42
Explorer
Mar 12, 2014
I put 4 L16's in my old sailboat... had over 800 amp hours of capacity.... could spend 3 days with the 12volt marine fridge running, lights, etc...... the vertical clearance would be an issue in my MH, and they do add a bunch of weight..however, they do perform well.........
JimM68
Explorer
Mar 12, 2014
L16? Interesting. Did some checking, L16's seem to have the same footprint as a GC2 but are taller. GC2 a/h rating is 220 to 250 depending, L16's are 400 plus!

Am I missing something here?
I "think" the L16's will easily fit in the battery tray in the Monaco...
And will double my boondocking time?
Sorry for the hijack
Pass42
Explorer
Mar 11, 2014
the 15" tall battery sounds like an L16H, much, much higher amp hour capacity than the smaller one..... and about 120lbs.........
LaTriker
Explorer
Mar 11, 2014
I purchased a hydrometer and checked my four batteries. Three batteries were good but one had a bad cell. I purchased one new battery at SAMs but it is smaller than the other three. The new battery is 9 1/2 " tall vs 15" on the existing batteries. Does the larger size mean they are stronger? Am I okay the use the smaller size battery?
Ozlander
Explorer
Mar 11, 2014
2oldman wrote:
LaTriker wrote:
. Normally, the bulk charging phase last much longer one, two, or even 10 minutes, unless I have a problem.
You must have a big charger for bulk to last only that long.. or your batteries are not discharged much.

Or a bad connection somewhere.
wa8yxm
Explorer III
Mar 11, 2014
"Does that sound like an inverter problem or are the batteries shot"

Option 2: Batteries shot.

HOWEVER a digital volt meter will confirm.. Could be a bad connection between battery and inverter.. In fact that would be "Suspect #1" in my book. Clean the battery terminals as first step.
2oldman
Explorer II
Mar 11, 2014
LaTriker wrote:
. Normally, the bulk charging phase last much longer one, two, or even 10 minutes, unless I have a problem.
You must have a big charger for bulk to last only that long.. or your batteries are not discharged much.
LaTriker
Explorer
Mar 10, 2014
Will get a hydrometer tomorrow and check the batteries. If the batteries are bad, I am looking at buying a new set at SAMs. Can anyone comment on Energizer 6 Volt Premium Batteries - Group Size GC2 for $112.68 each?
JR45
Explorer
Mar 10, 2014
Get a Hydrometer and check each cell, you may have a bad cell. At 12.5 they are not fully charged and to drop to 10.7 they are dead. Mine 4 batteries flot at 13.6 same with my starting battery 13.6 I would think your inverter is ok mine is on inverter all the time because of the RR frig.
JR
LaTriker
Explorer
Mar 10, 2014
I was incorrect in stating that the charger was on. Yes, I do have an inverter/charger. When on shore power, or generator, the inverter/charger display in the MH shows if the charger is bulk charging, absorb charging or float charging. Normally, the bulk charging phase last much longer one, two, or even 10 minutes, unless I have a problem. What I do not know is if my problem is the inverter or bad batteries. I did top off the water in the batteries three weeks ago.

Forum Discussion

Battery Problems

12 Replies

About Motorhome Group

Related Content

AG battery switchover

Battery problem

Battery Problems

Atwood water heater problem

Battery problem?