Hi guys!I figured the folks here could explain to me what's going on with the batteries under the hood of my truck.I have a 2006 Dodge Ram diesel 4x4 short bed truck. It has 70,000 miles on it and mostly used to haul my camper in it's bed. The camper has 200+ watts of solar panels controlled with a Morningstar Pro Star PS-30 PWM controller. There's a Blue Sea battery isolator so that my truck's batteries are charged after my camper's batteries reach full charge. It also allows my truck's alternator to charge my camper's batteries. So, with all that said, my truck's batteries are currently 4 years old and they measure 12.4 volts after sitting overnight. Voltage during driving or solar charging is 14.4 volts. Right after shutting off, with the camper off the truck, the batteries are around 13.6 to 13.8 volts. Over night, they drop to 12.4 and stay there for days.Specific gravity of all the cells, this truck has two Group 65 FLA batteries, is between 1.25 and 1.26. I've taken the batteries out and placed on a bench with a voltage controlled power supply. Current draw drops to zero at 14.4 volts, so I can't boost the specific gravity unless I put a higher voltage in. If I put 15.2 volts into the battery I can get a current draw of 4 or 5 amps. Not sure that's what is good though for the battery, just info for you experts. Anyways, battery resting voltage is 12.4 volts, specific gravity of electrolyte is 1.26 across the cells. I have a load bank, 100amps. Hooked up, it states green/good as I throw the switch and hold it. I only hold it for 15 or 20 seconds, but the needle stays in the green zone. I suspect my battery is starting to sulfate and these readings indicate it's starting to just get old and wear out. Any thoughts?

Should be ok for another year or so IMO. I would equalize them if you have the chance, to help with that.You also have parasitic loads in the truck drawing down the "resting" voltage. Could use a maintenance charger on them if sitting a long time between trips or taking many short trips in town so they never get recharged.

Do the batteries drop to 12.4v sitting on the bench overnight, or only if in the camper? Also when sitting on the bench make sure you don't have the batteries connected to each other while sitting overnight. You don't want a failing battery to drag the other battery down with it.

The way I look at it, batteries start truck they are good!Batteries fail to start truck they are bad time to replace both!

BFL13 wrote:Should be ok for another year or so IMO. I would equalize them if you have the chance, to help with that.You also have parasitic loads in the truck drawing down the "resting" voltage. Could use a maintenance charger on them if sitting a long time between trips or taking many short trips in town so they never get recharged.I agree, I probably have a year or so left in the batteries, but I got these from Costco back when they sold the Kirkland branded car batteries. Warranty is for full refund up to 4 years and 100 months prorated. I'm right at the point where I can replace them virtually for free, but since Costco now only carries the Interstate brand, the 100 month prorated goes away, just 42 months full refund. I don't have parasitic loads. Based on Dodge truck forums, there should be 30ma of current draw when the truck is off. I measure mine and sure enough; 30ma after about a minute or so after shutting off the key. that's .03amps. Since the truck normally has the camper and solar charging things, I'm pretty sure they are fully charged. But just to be sure, I did leave it on a charger for over 48 hours trickle. Nothing changed after I disconnected the charger; next morning, batteries at 12.4 volts.

opnspaces wrote:Do the batteries drop to 12.4v sitting on the bench overnight, or only if in the camper? Also when sitting on the bench make sure you don't have the batteries connected to each other while sitting overnight. You don't want a failing battery to drag the other battery down with it.I have a mechanical disconnect and disconnected, still drops to 12.4. Both do the same.

Truck battery eval | Good Sam Community

brulaz
Explorer
Feb 08, 2017
Your 2006 maybe different but when the batteries died in my 2016, the Cummins could not be jumped. Not with my RV's fully charged 220Ah bank, or with a HD diesel tow truck.

But these batteries were dead, dead, dead. There were no lights and not even a solenoid click when attempting to start. They had to be replaced. This happened after letting the truck sit for 6 weeks.

I would hope that less fully discharged batteries can be jumped though.
Ski_Pro_3
Explorer
Feb 08, 2017
BFL13 wrote:
trail-explorer wrote:
You are overthinking it. If the truck starts fine, keep the batteries.

Load test them at an auto parts store. That's going to tell you more than taking voltage readings.

If the starter is sluggish and turns over the engine slow, replace.
Done.

That's the typical regime with starting batteries.

All true, but if way off grid you don't want be stuck so far from a battery store and no wheels to get there anyway.. Campers should have a way out of that.

A. start the truck from the trailer batteries if the truck batteries die.

B. always carry a 10amp (say) portable charger in case your converter dies.

C. have some solar in case you run out of battery

D. take a portable gen in case your installed gen dies and there is no solar due to whatever (trees, overcast)

Thanks for the suggestions. I do have my camper batteries, the charger for the camper batteries, a genny, solar too.

I guess I'm just a belt AND suspenders sort a guy. I'd kick myself if my batteries crapped out at a bad time and I had ignored the early signs.

Many times I tow a little Suzuki Samurai. Ha!
BFL13
Explorer II
Feb 08, 2017
trail-explorer wrote:
You are overthinking it. If the truck starts fine, keep the batteries.

Load test them at an auto parts store. That's going to tell you more than taking voltage readings.

If the starter is sluggish and turns over the engine slow, replace.
Done.

That's the typical regime with starting batteries.

All true, but if way off grid you don't want be stuck so far from a battery store and no wheels to get there anyway.. Campers should have a way out of that.

A. start the truck from the trailer batteries if the truck batteries die.

B. always carry a 10amp (say) portable charger in case your converter dies.

C. have some solar in case you run out of battery

D. take a portable gen in case your installed gen dies and there is no solar due to whatever (trees, overcast)
Searching_Ut
Explorer
Feb 08, 2017
You're probably wise to have replaced the batteries being as how you camp remote, and apparently harsher conditions than many. 4 years isn't bad for a vehicle battery, especially if used in somewhat extreme conditions, with excess heat being something vehicle batteries are often subjected to, especially if you're often pulling hard while the battery is charging as happens in desert climates.
trail-explorer
Explorer
Feb 07, 2017
You are overthinking it. If the truck starts fine, keep the batteries.

Load test them at an auto parts store. That's going to tell you more than taking voltage readings.

If the starter is sluggish and turns over the engine slow, replace.
Done.

That's the typical regime with starting batteries.
westend
Explorer
Feb 07, 2017
Interesting but that isn't the same battery in my truck. When the Sun comes up, I'll open the hood, get the numbers off it, and edit this post.

Edit: Well, I checked out the battery and the part and serial number spaces are blank. There is a "made in Mexico" stamp on the case, though. Since Johnson Controls has a plant down there, it could probably be presumed it is made by Johnson.

This battery is labeled "Motorcraft Max" and "Max power", not that it means a darn thing, just different labeling.

I have no idea if the original I got 10 years from is this same battery or not. I did buy it at a Ford dealer but that means little. BTW, those were not an easy 10 years by any means, 2000 W sound system and a cranky door sensing switch that keeps the cabin light lit long after the key is removed.
Ski_Pro_3
Explorer
Feb 07, 2017
The kirkland branded battery and the Motorcraft battery are one and the same; Johnson controls 65850. You should be able to see that # on the top of your Motorcraft battery;
westend
Explorer
Feb 07, 2017
I've read other bad things about the Kirkland branded batteries.
The Motorcraft battery in my truck lasted 10 yrs 1 month. I replaced it with the same.
time2roll
Nomad
Feb 07, 2017
Missed the comment about a code for weak battery. Yes replacement now is best.
Ski_Pro_3
Explorer
Feb 07, 2017
time2roll wrote:
100 amp load is a bit light for testing. Need to be closer to CCA unless the indicator adjusts for this.

I thought I read MEX said these 65s were often acid starved and that may account for the low voltage and specific gravity.

I would just keep running them. Test in 12 months to see if the numbers keep dropping.

For a superior replacement consider Bosch or Odyssey AGM.

I don't have a carbon pile for a load, just the 'toaster' 100amp load.

I would have kept running but for two things; I am getting engine codes and I camp remote. Bad time to have a battery crash on me in the Sierra's in the winter.

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