Group 31 Batteries

[Shadrach]

Has anyone put group 31 batteries ( brand not important right now) in a 3rd gen? The originals are group 65. 31's are tougher - will take more vibration - and are available with more power. They are the common battery used in big trucks, KW etc and are available at any truck stop/truck shop. They're about the same price as a good group 65.

Shadrach

 

[NIsaacs]

I think the 31 is too long to fit. That is the size the single battery 1st. gens used.



Nick

 

[mwilson]

Shadrach,

The group 31's are not going in there without a little modification.

See this thread from a while back and the part number for the Cat group 65.

That is what I will get when the time comes.



https://www.turbodieselregister.com...iscussions/218514-optima-batteries-again.html



Mike

 

[JBonpua]

Someone on one of the forum (I forgot which one), installed an Optima 31A. I have two 31A just waiting for the original battery to quit and I will put it in. If you remove the blanket it will fit although very tight.

 

[Shadrach]

I did a little filing on the plastic box and they will fit. I will need to make up a new hold down system, but that's minor. They weigh about 50% more. Group 65 are 12 x 7 1/2 x 7 1/2. Group 31 are 13 x 6 3/4 x 9 3/8. They cost about the same if you go to a truck supplier. I'll post pics later. Shadrach

 

[Hercules130]

i just got a set of Diehard Platinums. So far So good.

 

[Shadrach]

I now have 2 new group 31 batteries in my 03 Dodge. With a little grinding of the plastic edges they fit. It's a good thing the new batteries have handles as I had to lift them in and out several times. At 60 # each and having a 4x4 you get your exercise. I did have to do a couple of mods that I hadn't planned on. On the pass side the alt cable and the neg battery cable aren't long enough. Group 31 batteries are not only taller but the posts are in the moved towards the middle of the ends instead of being near the corner of the battery. So I will have to length the cables. Here are some pics of 2 old batteries I had lying around, the small one is a group 65 and the larger one is a 31. Group 31's come with either post or threaded stud. I decided on automotive post style as that's what my cables are and there is also more contact area that on a stud. I'll post pics of them mounted when I get the hold downs made.



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[seafish]

Shadrach. . I have been planning on doing some sort of the same thing that you have just done on your truck with the Group 31 batteries.

I do have several questions for you that I am hoping you will try to answer.

Did you use the Group 31 Marine Grade DieHard Platinum?? This one--

http://www.sears.com/shc/s/p_10153_...ine+Batteries&keyword=diehard+platinum+marine


Today, I measured the oem battery tray on my 2005, and it seems as if there is JUST enough room to fit in the longer Group 31 battery onto the stock tray, although that might not include the thermal blanket that surrounds the battery. I do not know if the AGM type batteries need the blanket or not. Were you able to keep yours on the battery??

Also, I am unclear as to whether you filed the battery casings or the oem battery trays. Either way, could you explain in more detail as to what you did??

It seems to me as if filing down the tray will actually weaken the tray substantially by removing the right-angle aspect of the plastic gusset. I am wondering what your take is on that??

I really like the idea of the Group 31 Diehard Platinum batteries in my truck, but given their additional weight, I DO want them to be well supported. I did have the idea of pulling the trays, trimming them back, and then riveting or epoxying some aluminum angle struts to the OUTSIDE of the tray.

Even though some people have done so successfully, I am NOT much interested in removing material from the outside of the battery casing as I am concerned that might create a warranty issue if there ever was a problem with the battery.

 

[Shadrach]

First that's an expensive battery. To rich for me. I bought mine ( Truckers Best Batteries ) at a local truck supply place (Fort Garry Industries - for you Canadians on here ) for ;ess than $100 each. My buddy has had good success with them. They are 925 CCA /1100 amps. If I had wanted to spend more I could have got higher rated ones. I did file off the edge of the tray. You don't have to take off much. I took off more than was necessary in some places. Yes technically it would weaken the tray as the lip does give support. I'll have to keep an eye on it for cracks or bending. You'll see in the pictures that I will take this weekend. Taking the trays out meant removing the inner fender, so I practiced on my spare tray first. If you file off some about 1. 5-2" down from the top the corner of the battery fits in the notch that you just filed and then sparingly take off just enough for the battery to fit. No I didn't keep the thermal blanket. Shadrach

 

[seafish]

First that's an expensive battery. To rich for me. I bought mine ( Truckers Best Batteries ) at a local truck supply place (Fort Garry Industries - for you Canadians on here ) for ;ess than $100 each. My buddy has had good success with them. They are 925 CCA /1100 amps. If I had wanted to spend more I could have got higher rated ones. I did file off the edge of the tray. You don't have to take off much. I took off more than was necessary in some places. Yes technically it would weaken the tray as the lip does give support. I'll have to keep an eye on it for cracks or bending. You'll see in the pictures that I will take this weekend. Taking the trays out meant removing the inner fender, so I practiced on my spare tray first. If you file off some about 1. 5-2" down from the top the corner of the battery fits in the notch that you just filed and then sparingly take off just enough for the battery to fit. No I didn't keep the thermal blanket. Shadrach

Thanks for the reply... I look forward to the pics~~~Oo.

 

[Shadrach]

This is the left side of the drivers battery. You can see how I have notched the lip so the larger group 31 battery fits. I also trimmed the lip more on the left side of this battery because there is a bolt head sticking into the tray on the right side for the antilock brakes. The notch helps the battery from sliding to the outside of the case. I still have to make up new hold downs.



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The batteries are taller but you can see how high the 6. 7 air box sticks up. ( I know - the cables not on properly. )



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I had the left side negative cable lengthened as well as the alternator to positive post cable. The lug end was cut off and then a new piece of cable spliced on and a new lug. It helps that my buddy is a HD mechanic who specializes in electrical repairs as well A/C.



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Shadrach

 

[Shadrach]

I came across this picture I took when I was getting ready to pull the engine showing the drivers side battery. Although they are taken from different angles you get the idea.



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Shadrach

 

[seafish]

Thanks for the pics... looks good!!!