replace battery in Dodge Ram

[Donald]

I disconnected one battery and tested both in my Dodge Ram. It seems the secondary battery did not pass a conductance test nor a load test. Its a Mopar battery by JCI.

Someone said I should replace both primary and secondary. I would just as soon not if not really required.

I do not have any problems with the truck and just decided to check both batteries. Would not have known otherwise.

 

[JHZR2]

are they in parallel on the DC bus?

If so, Id replace both. Otherwise one will draw from the other, and under load, one could go into reversal and do bad things. Ive also seen lead-acid battery fires from mismatched parallel batteries.

 

[Chris142]

You should replace both as a set. If not the old one will drag down the new one. Infact look for the same build code if possible.

The new batt will supply more cca than the old one and will die early.

 

[bullwinkle]

They'll be in parallel. I had a similar problem on my '06, one tested excellent, one was weak-if the truck sat for more than a week without running it wouldn't crank fast enough to start & throw a CEL. Put in 2 new Interstate Megatron Plus batteries, no problems since-3 years ago. I use the remaining good one in the boat.

 

[bullwinkle]

If you're price shopping I've also had good luck with the Walmart Everstart Maxx batteries, I put a set in the F-450 & those have also been good.

 

[fdcg27]

Diesel+winter on the way+living way out in the boonies?
I'd replace both and not have to worry for the next five or six years.
AAP coupon codes are your friend for things like this, although you might have to buy the batteries in two separate transactions to achieve maximum savings.

 

[Donald]

Originally Posted By: Chris142
You should replace both as a set. If not the old one will drag down the new one. Infact look for the same build code if possible.

The new batt will supply more cca than the old one and will die early.


While that kind of makes sense, I could buy two identical ones and one could fail a month after I buy it dragging the good one down. Might not even notice.

 

[Donald]

Originally Posted By: fdcg27
Diesel+winter on the way+living way out in the boonies?
I'd replace both and not have to worry for the next five or six years.
AAP coupon codes are your friend for things like this, although you might have to buy the batteries in two separate transactions to achieve maximum savings.


Actually I have the pickup and a Jeep (both for me). While the 2WD pickup gets better mileage, the Jeep is driven if there is a hint of snow.

 

[fdcg27]

That big, heavy Dodge actually gets better mileage than the Grand Cherokee?
I would have thought the reverse, diesel or not.

 

[Donald]

The pickup gets 25 mpg and the Jeep about 19 mpg.

 

[fdcg27]

25 mpg?
That's really very good for that type of vehicle.
Our Forester can barely do that, although Subaru's been teasing the faithful for years with talk of bringing their HO diesel to America.

 

[The_Jeff]

Save your good battery and its test slip, I bet you can get $35-40 for it on craigslist.

Just say you replaced it as part of a set and it was the best of the old.

Lots of folks don't have $120 for a battery.

 

[Donald]

I have the bad battery hooked up to my BatteryMinder which also desulfates. Maybe a day or two of that will help it.

I looked into the good battery cells (added water) and got a good view of the plates. I could see a light brownish coating on most of the plates. Is that sulfation? And this is the good battery.

Not sure exactly what I am looking at. Not an expert at battery plate construction and chemistry.