Humvee Upgrade: Best HMMWV Batteries
Power hungry modifications
Most surplus HMMWVs will receive all or some of these modifications for civilian use:
- 24v to 120v power inverter for plug-in items like laptops
- 24v to 12v converter for standard automotive accessories
- 12v interior lights
- a radio/stereo
- 12V power outlet
- back-up camera system
- communications radio(s)
- off road lighting
- electric winch*in most cases, an electric winch is the biggest load you might put on your batteries.
Best Choice – a Deep Cycle battery
To best handle these additional loads I recommend going with a dual-purpose “deep cycle” battery. “Dual purpose” refers to the primary purpose of supplying power to the starter, as well as the secondary purpose of supplying ongoing power to other items. The ongoing additional load can cause a deeper discharge, which damages standard starting batteries. Deep Cycle batteries are designed to better handle being discharged more and more often.
With all of the vibration and rough use expected of surplus HMMWVs, I recommend a rugged battery like a sealed, AGM Optima Yellow Top. You could maybe go cheaper with a standard fleet 6T battery, but the sealed Optimas will likely serve you better.
Model # 8012-021 D34
If you aren’t going to install the accessories listed above, then a deep cycle battery may be overkill. A standard “starting battery” may be sufficient. Again, I like the more rugged, sealed AGM batteries… this time, Optima Red Top Group 34 starting batteries.
Model #8002-002 D34
Are the Optimas as big as the 6TL military batteries?
Nope, but you can install Optima batteries in a Humvee using standard HMMWV battery cables and hold downs. However, I suggest getting Optima base adapter(s) that gives each battery a larger footprint so they don’t move around. I have read that Optima made a HMMWV battery tray adapter, but discontinued production some years ago. However, a quick eBay search turned up various aftermarket Optima Battery trays for HMMWVs (eBay search link). The extra space in the battery box freed by the smaller batteries can be used for installation of a 24v to 12v converter.
Other HMMWV battery options
The Project Humvee Battlewagon has a pair of recent Military Hawker HASP-FT Armasafe AGM batteries pulled from a HMMWV about to be scrapped by Southern Metals Recycling. These retail for about $600 each. If I had not gotten a deal on these used batteries I would have gone with Optima Yellow tops. Here are two data sheets and an article on charging Hawker batteries:
- Hawker HASP-FT Armasafe AGM batteries data sheet (pdf)
- Hawker HASP-FT Armasafe AGM batteries manufacturer data (pdf)
- New charging protocol for Armasafe Hawker AGM batteries (offsite link)
While I have never gone to any local or national chain parts stores looking for a 6TL battery, I am told they aren’t that hard to find.
I have read other HMMWV owners report good luck with:
- Odyssey PC2250ST Battery – Note I received from a HMMWV owner: “I run group 34 odyssey batterys in my hmmwv. They provide plenty of power at half the cost.” This one is interesting as it has marine type accessory posts that could come in handy for adding 24v to 120v power inverter or 24v to 12v converter. Also, Odyssey and Hawker are owned by the same parent company, Enersys-Hawker. I’m told that the Hawker and Odyssey batteries are the same, but with different labels.
- Interstate 6TL batteries
- Exide 34 AGM – I have no personal experience with these, but at $160 each, if they work as I have heard, these may be the best deal
- Napa 6TL
- Group 24 batteries – I have read that these will work, but they seem a bit small for this application.
Other batteries that appear compatible, but I have no first hand reports of HMMWV use:
- I found this battery cross reference chart on a retail website:
Interstate A6TL Interstate 6TL Deka 6TMF Hawker Armasafe Plus Hawker 9750N7025 Fiamm FGMX12120 NSN 6140-01-485-1472 Exide 6TL 6TL Military Ordinance Battery
These are the batteries that were in the Project HMMWV Battlewagon when purchased from the US Army. I was able to recover one of them to around 12.5v using this smart battery charger (link), but the other won’t hold a charge at all.
HMMWV battery cable routing
These pictures shows the proper routing of the HMMWV battery cables to put the two 12v batteries in series and deliver 24v.
Battery box integrity
If battery acid leaks from either battery it can eat the aluminum floor of the battery box. There are new aluminum floor sections available to replace a damaged floor (part 12338765 NSN 6160-01-470-41
Driving the HMMWV regularly with a properly functioning charging system will help. However, I have found that the use a desulfating battery charger can actually restore some lost battery capacity that was lost over time as the battery became sulfated during use.
My 1-2 punch for battery maintenance:
- This smart battery charger (link) for charging if the batteries get low, like if I leave the lights on by mistake. I disconnect the negative terminal and charge the batteries one at a time in the battery box. The charger senses the condition of the battery and charges fairly quickly if the battery is “healthy”. If it needs it, then the charger automatically goes into a desulfating mode that I have seen take anywhere from 6 to 12 hours. You can actually hear the desulfation process causing bubbles inside the battery. This charger has saved a few older automotive batteries that would no longer take a charge in the vehicle.
- A military surplus Pulsetech Solargizer IS-24-L, which shares the same part number as the 24-Volt Solargizer Model 150. Before hooking up this solar powered battery charger and desulfator my HMMWV batteries were often a bit on the low side if the truck had not run in a few days. Since installing the Solargizer the batteries have been at full charge every time I have checked, even when the Humvee wasn’t run for several days.
More HMMWV articles can be found under the Humvee category menu above or by clicking HERE. You might also like the HMMWV section of our Amazon store where we have listed lots of replacement and upgrade parts for Humvees. We have also found a lot of HMMWV parts on eBay (link).
Please leave a comment if you have suggestions on how to better install LED tail lights in a HMMWV.
Gear Report acquired a real HMMWV (High Mobility Multi Wheeled Vehicle) from the US Army for use as our official field and shooting range vehicle. We have already posted about some of our upgrade projects (Project Humvee Battlewagon article links) and have a lot of really cool projects on the way. Consider subscribing so you don’t miss any of the cool reviews as we post them.
Here is our Project Intro (link) and our list of DIY HMMWV upgrade projects.