What batteries do I need

[Maineforlife87]

I have a HMMWV M1123 with a 6.5 non turbo engine looking for what size batteries I need for it any information would be greatly appreciated thank you

 

[Mullaney]

I have a HMMWV M1123 with a 6.5 non turbo engine looking for what size batteries I need for it any information would be greatly appreciated thank you

.
You can use 24 or 27 series standard batteries.
Or, you can use the factory type (almost square) batteries.

 

[TNDRIVER]

I have a HMMWV M1123 with a 6.5 non turbo engine looking for what size batteries I need for it any information would be greatly appreciated thank you

6T's from the Government side. Group 24 are the right size height wise. I will not give advise but tell you what I've done. One truck has Odyssey 6t's , one replaced under warranty but will not use them again they have become stupid expensive. The other truck has Wall World Group 24 AGM's . The W W batteries have a better warranty (It seems to change a bit depending on where you live.) and price. The same battery is available from the usual suspects but more expensive. If you use the 24's place some blocking and/or anti skid material under/ around the bottom of the batteries. Works for me.

 

[Milcommoguy]

DITTO with the gorilla guy. Warranty and availability, over the counter at discount stores. Lasts just has long, a LOT easier on the wallet & 6TL's too damm heavy.

Be nice to them.. They don't have 9 lives. PMCS, don't leave them dead or dry, over / under charged (float) and figure 5 years. My old auto shop teacher said "Wet cell battery has two states. Charged and discharged" Not a very good storage battery

IMO...Don't monkey around with got's to be OEM, CAMO

 

[TOBASH]

$60 24f from Wallyworld

 

[Mogman]

Do you have a "company" Interstate battery store near you?
If so I would look to see if they have any AGM "recon" group 24, 27 and IIRC someone managed to stuff some group 31 batteries in there.
I have had real good luck with the "recon" batteries which are 99% just batteries that the shelf life has expired on.
I personally would never run standard lead acid batteries in a passenger compartment because of the chance of a hydrogen explosion given the rather sealed battery compartment the HMMWV has and of course if you are ever unlucky enough to roll it then you have an acid spill to deal with although there would be a rather small chance of that happening.
I had a real bad run of Wally World batteries, three that just quit, no warning and no output, but your mileage may very..

 

[TNDRIVER]

$60 24f from Wallyworld

AGM's ,you can dunk them. Not $60.00

 

[Coug]

Best: AGM. will hold up better to abuse and vibration than flooded.

Second best: Maintenance free flooded lead acid. don't need checked monthly for fluid level.

Last place: flooded lead acid. Will need checked monthly for fluid level and topped off with distilled water as necessary, will leak if tipped or shaken badly, and when charging (and especially if overcharged) create hydrogen gas and oxygen, essentially turning the battery compartment into a small bomb (and yes, I've seen pictures from the explosion)


As for size, 6T is what the military uses, but that's simply because they use those in larger trucks, and supply chain logistics for that large of an organization it's easier to use an oversized battery than stock multiple sizes. Major downside of 6T is in the civilian world they are considered a Commercial/Specialty battery, meaning a lot of places don't stock them, and they only come with a 6 month warranty. Also much more expensive than a comparable quality group 24 battery, that at minimum comes with a 1 year, and can be found with 4 year full replacement warranties.

Group 24 with flat tops (usually either AGM or maintenance free) will work with the original hold down bracket, making install very easy (there is a 1/2" thick board in the front and rear to keep them from shifting since the positive post is kind of close to the front of the battery box)

 

[MarkM]

I went with the Optimas and haven't looked back after 4 years and going strong.

Mark

 

[thompsoncustom]

I see most people run group 24 I personally run group 65 which probably wouldn't work unless u had custom hold downs or don't run them (mine never came with them). But the biggest reason I run 65 series is because that's what I have in every vehicle I own cars/trucks/ and a humvee.

 

[Coug]

Basically, any batteries that you can make fit into the battery box, or any other location that you want to use (the H1 uses a holder near the front passenger tire)

The original 6T battery was only rated for around 660 CCA, so anything above that will be fine, though more is better if you live in a colder climate. The H1 uses a pair of 800ish CCA batteries. If I recall correctly RWH (Retired WarHorses) who owns/operates a shop that has specialized in HMMWVs for decades said that one truck came into the shop with a pair of lawnmower batteries and was starting okay, but that is also in California where it's usually warmer most of the year.

The 6T has huge reserve capacity, basically a lot of power that can be used while the engine is off for things like radio equipment. Most of the batteries we've mentioned are 1/2-2/3 the RC of the 6T, but unless you want to operate a bunch of stuff for a long time with the engine off it doesn't make a difference. You can always add additional batteries under the rear seat of elsewhere in the truck to run non-essential equipment if you want to.

 

[Godspeed131]

I’m apparently in left field lol with group 34s in mine. Currently running Interstate MTX-34 agms. They are a little shorter and not as long so I had to use some highly engineered natural wood decking boards for spacers but makes it fit nicely. So as can be seen pretty much any decent battery will work doesn’t need to be exact.

 

[BadAmish]

I went with the Optimas and haven't looked back after 4 years and going strong.

Mark

@MarkM - What are those red ring (insulators?) around your battery connector cables? Where did you get those?

 

[country]

ALL-5409 | Battery 6TMF 12 Volt Wet Battery M35A2 HMMWV M809 M939 FMTV LMTV Oshkosh
Battery 6TMF 12 Volt Wet Battery M35A2 HMMWV M809 M939 FMTV LMTV Oshkosh
NSN #: 6140-01-446-9506
Part #: TYPEII, 3374368, 347/20670, ATPD 2206, 5934818
$119.00


ALL-5410 | Set of 2 6TMF 12 Volt Wet Battery Type II
Set of 2 6TMF 12 Volt Wet Battery Type II
NSN #: 6140-01-446-9506
Part #: TYPEII, 3374368, 347/20670, ATPD 2206, 5934818
$225.00


ALL-5411 | Set of 4 6TMF 12 Volt Wet Battery Type II
Set of 4 6TMF 12 Volt Wet Battery Type II
NSN #: 6140-01-446-9506
Part #: TYPEII, 3374368, 347/20670, ATPD 2206, 5934818
$435.00

 

[MarkM]

Mine were on the truck when I got it but I found these for you.

Mark

Mil spec battery insulators.

 

[LCA078]

Short answer is you have lots of options.

Military spec batteries are big and heavy because they want to have a lot of reserve power to crank under extreme conditions (really cold) and with engines that are hard to start (i.e.- require lots of cranking time for various reasons) and sit in motor pools untouched for long periods of time. If you aren't operating in extreme conditions, your motor starts after only a couple revs of the starter, and you keep the batteries maintained (charged by driving the vehicle once or twice a month) then practically any battery that "fits" will work for you but since you're in Michigan, I recommend not the "bottom" batteries with low cold cranking amps. Group 24's seem to be the norm here as they "fit" and have decent cranking amps (~700 amps).

I'll assume you'll want a "decent" battery that offers the most value for the dollar which is how I shop for batteries.

A couple days ago in Austin, I picked up a pair of 24's from Costco for $129 each. 700 cold cranking amps (cca), weigh 43lbs each, and have 3 year prorated warranty. The Interstate battery dealer across town only had 1 blemish for $75 so I passed on it and grabbed the pair from Costco as it wasn't worth the hassle to drive across town.

Wally World has the $69 group 24F (reversed terminals which shouldn't matter for HMMWV) which have 585 cca, weigh 38lbs and a 1-year free replacement warranty (per W W product page).
Wally World also has the $149 "Maxx" group 24 with 700 cca, weigh 37lbs with 3 year free replacement warranty (per W W product page). Looks like you're paying double for more or less the same battery in order to get the extended warranty (at least that's what I believe).

I have no idea why the Maxx weighs a lb less per the descriptions but generally more weight means more lead which means either more plates (more cca) or thicker plates (more resistant to vibrations and shock). This is why I just buy the heavier batteries from Costco and be done with it.

What's interesting is W W also has the marine version $93 group 24, 1000 mca, 1-year warranty with the additional wing-nut posts if you need to add accessories with eye terminals. But don't get fooled by the 1000 marine cranking amps which is measured at 32 deg F vs cca which is measured at 0 deg F. So this battery is probably really a 700 cca or so...

Bottom line: lots of choices for batteries, don't overthink it, and enjoy the vehicle.

 

[MarkM]

I highly recommend a Pulse Tech Solargizer 24V if you let the truck sit for an extended period of time. I don't drive my M998 during the winter up here in Massachusetts (rock salt) but I do start it up a few times during the winter. I swear by the little Solargizer.

Mark

 

[DREDnot]

Mine came with DEKA batteries from the auction. Group 34.

I installed a Ground cable battery disconnect switch and they have lasted over five years so far.

 

[GuntherRommel]

works

 

[LCA078]

Mine came with DEKA batteries from the auction. Group 34.

I installed a Ground cable battery disconnect switch and they have lasted over five years so far.

View attachment 955697

View attachment 955698

That's clean. Where did you install your ground disconnect? I'd like to do the same but haven't settled on a location for it. Would like it somewhat hidden, like in the back of the battery box accessible in the right rear passenger foot well but then again I know myself on how this will play out. I'll get in my truck and yell "Dang it- I forgot to turn on the batteries!" and I'll have to get out, walk around, turn it on, and get back in. So maybe thinking I'll put the cut off in on the front of the box so I can lean over and turn it. I'll have to sit in my truck and do some exercises to see where I can put it within reach but not so it's obviously in sight for all to see.