My two 6V Batteries were installed in my DRV in early 2015 when new. They have no labeling to tell brand. I would guess they are 4 years from mfg date or even older now.Normally I can drive for 10 hours or longer and when I stop the residential frig is 0 degrees freezer and 38 on top. I have a 1,000 watt inverter and yes it was on. This trip the freezer was the same but the top was 43 degrees. I checked the water before leaving and it was full. I checked the battery voltage and it was 11.5V.Thoughts?

At 11.5 volts the battery is about dead. Is charging voltage being supplied to the battery while under way?

Start the vehicle and then measure the battery voltage. IF the voltage goes up to 13.5 or more then you know the charging system is functioning, however the connections on the batteries must be spotlessly clean.That said, four years is plenty on unknown batteries. A hydrometer and load test would help but you already did a load test by running the refer. Lots of little unknowns here but one does not BUY batteries, we just rent them. If you use hookups mostly you can nurse more time out of the batteries but it is not worth the hassle. Too many things rely on good batteries.

Yes the truck is supplying power to the RV while towing. I drove 30+ hours from SoCal to DFW TX and the frig was at 0 and 38 upon arrival, this was about 10 months ago.So I am thinking the batteries are being sucked dry faster than they can charge because they are getting tired. I agree 4 years is a long time for RV batteries especially no name.Just thought I may be missing something.

our 4 batteries were new in Oct of 09 replaced in Dec of 14. Now it is 18 and I will be watching them and new will be installed. Batteries are the same thinking I have about tires. Earlier is better than later. have a great winter everybody. We are hitting the road tomorrow for Az one month later this season.chevman

What is the voltage to the batteries when towing?

Are my Batteries going bad? | Good Sam Community

25 Replies

MEXICOWANDERER
Explorer
Oct 20, 2018
Check to make sure they are not chronically undercharged and gradually sulfate. Take a sample sometime with a battery hydrometer and see if it reads 1.280 when you believe that batteries are fully charged.
Cummins12V98
Explorer III
Oct 20, 2018
red31 wrote:
I wonder if you actually cared for the batteries how long they might last?

Not sure what you mean but I kept them topped off. What else is there to do?
AllegroD
Nomad
Oct 20, 2018
We run our RR on 2 6v. Rarely off grid scept on the road.
red31
Explorer
Oct 19, 2018
I wonder if you actually cared for the batteries how long they might last?
Cummins12V98
Explorer III
Oct 19, 2018
camperguy99 wrote:
Unless you have increased the wire size from the truck to the 5th wheel I doubt if you are actually doing ANY charging going down the road. Between the frig and current draw of the even unloaded inverter could eat up all the available current from the trucks alternator. Been there done that. I had to parallel additional 10 ga wire from the truck back to the 5th wheel battery bank. Before about 7-8 amps, after greater than 20 amps. A clamp on current probe would answer all the questions.

As I mentioned up until this trip the frig stayed right on 0 and 38. It stayed that way on a continuous trip of over 30 hours. The truck does keep the batteries charged. The 1,000 watt inverter does a fine job also. I am convinced the batteries at 4 years are the issue.
ksg5000
Explorer
Oct 19, 2018
Pretty rare to find people running a big residential refrigerator on two six volt batteries - most run on 4 or 6. If you have been doing this a while maybe you should focus on whether your batteries where fully charged b4 you started your trip and how long your trip was?
camperguy99
Explorer
Oct 19, 2018
Unless you have increased the wire size from the truck to the 5th wheel I doubt if you are actually doing ANY charging going down the road. Between the frig and current draw of the even unloaded inverter could eat up all the available current from the trucks alternator. Been there done that. I had to parallel additional 10 ga wire from the truck back to the 5th wheel battery bank. Before about 7-8 amps, after greater than 20 amps. A clamp on current probe would answer all the questions.
2oldman
Explorer II
Oct 19, 2018
I mean running batts to 11.5 will cause battery issues. As in premature death.
time2roll
Nomad
Oct 19, 2018
Cummins12V98 wrote:
Just setting here plugged in I just checked the voltage at the digital meter, its 12.9. Turned off shore power and it was 12.3. Turned it back on and it was 12.5 and checked a couple minutes later it was 13.1. Even a few more minutes it's 13.7.

I am going to get a couple 6v Interstate batteries from Costco.

Heading out on a 5 hour trip next week I will report back how well the frig stayed cool!
12.9 plugged in seems low.
Unplugged dropping to 12.3 seems bad unless a heavy load.
12.5/13.1/13.7 sounds like something started working again.
Does not seem consistent with the start at 12.9

Anyway connecting to the running truck should also pop the voltage up some.

Good chance the batteries are shot. The replacements should get you working again.
Cummins12V98
Explorer III
Oct 19, 2018
2oldman wrote:
Cummins12V98 wrote:
As I mentioned I have had zero issues up to this last trip.
Running batteries to 11.5 will cause issues.

This is true as in brakes not working as they should. Had that happen on last DRV.

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Are my Batteries going bad?

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