Engine/Transmission (1998.5 - 2002) group 34 vs group 65 size batteries

[JCyrbok]

Other than possibly a size/fitment difference, is there any other problems with putting group 65 batties in a 2001 that came stock with group 34 batteries??



My group 34 optima red tops are starting to get long in the tooth at just over 10 years thinking about changing them out before I get stuck somewhere.



J-

 

[seafish]

Fitment is the only issue.



This is a link to maximum dimensions of ALL auto and truck group sizes--



BCI Battery Group Size Chart



The group 31 is listed near the bottom under heavy duty commercial batteries.

The group 34 and 65 are listed under passenger car/light duty commercial.



My 3rd gen takes a Group 65 but with some careful case trimming, many people are getting the Group 31 HD battery to fit. It has substantially more CCA and RCT then the the 65--



Just for reference, here are the specs for the Sears Platinum (rebranded oddyssey) Batteries in all 3 group sizes--

 

[JCyrbok]

cool thanks seafish, thats kinda what I thought.



J-

 

[Bob4x4]

The 01 diesel truck came with group 27 batteries not 34.

I have changed my 94 over to 65's just for convenience so both trucks have the same Batteries,I did fab new brackets to run the 65's in the 2nd gen because they are shorter.

 

[TPringle]

Did I understand correctly, that is 10 years out of Optima batteries? Is this normal for these? I have seen them, quite a bit more expensive, of course. Maybe worth it tho.

 

[Tractorat]

I just changed out my 2002 OEM batts last year just because. They were still great, no problems. I put in interstate gtoup 27's, which are the OEM size. I expect to get another 10 plus years out of them. Unless you live way way north, and it gets to be over 110 d daily in the summer, I really dont know why you need a bigger battery.

 

[JCyrbok]

Did I understand correctly, that is 10 years out of Optima batteries? Is this normal for these? I have seen them, quite a bit more expensive, of course. Maybe worth it tho.

yep i got 10 year on my optima's in michigan winters (it was -3 yesterday) and summers (hits 90's). I think i am on the lucky side, which is one of the reasons that I am looking to change them out before I get stuck somewhere.



I have heard that the newer optimas (like in the last 5 years) are not the same quality as the olders ones. I seem to remember reading that they moved their manufacturing to mexico maybe.



Bob gotcha on the group 27's, I should worded it differently,I have group 34 optima's currently (thought that was the stock size, lol).



Thanks

J-

 

[Bob4x4]

Yea I quit buying optimas to,the new ones just don't last like they used to. .

Only got a couple years out of them in the trailer and of course just past the warranty period in the Jeep as well.

 

[WWillisJr]

How about just running a battery tester across both of your Optimas instead of just changing them out? This will at least let you know the "health" of your batteries, and give you an idea of when you might need to change them.

I've had Optima Yellow Tops for the past 5 years, still at 100% each.

 

[EMAC2]

Guys, just curious. If the grid heater circuit is deleted (it's usually warm here) do you think just one battery will start / operate the 6. 7L. Just asking.....

 

[Bob4x4]

Guys, just curious. If the grid heater circuit is deleted (it's usually warm here) do you think just one battery will start / operate the 6. 7L. Just asking.....

I would not do it. It is amazing what the vehicle electronics monitor and how the systems work. I have had a bit of training in electronics starting back in the USMC and of course more every year but these trucks... ... ... ... even the engineers learn after the trucks are on the road

 

[NIsaacs]

I agree with Bob, the electronics need two batteries. Even on my '01, the last time I changed them out, I ran only one new one while I was waiting on hold down parts and it caused weird issues.



Nick

 

[cerberusiam]

Guys, just curious. If the grid heater circuit is deleted (it's usually warm here) do you think just one battery will start / operate the 6. 7L. Just asking.....

The 2 batteries are not there just for the grid heaters and starter, the electronics require a clean static voltage supply to operate effectively. While they will run with one battery it is far from optimal.



Uou wil just end up replacing a single battery that much faster due to the load so it really ends up being a zero sum game.