H3 Upgraded Battery


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When it’s time to replace the battery in that H3 Hummer, I recommend getting the Optima Battery 8022-091 75/25 Red Top or the Optima Battery 8042-218 D75/25 Yellow Top even though the two Optima D75/25 batteries are much bigger than the factory battery and will not fit inside that plastic box. I think that the plastic box is just there for cosmetics reasons and to cover up how small of a battery that Hummer came with from the factory. So I ditched that small battery and the cheap plastic box to install a much bigger battery in its place. The reason being, the factory battery isn’t going to hold up to heavy winching and I need a convenient way to connect my winch to the battery.

The Warn M-8,000lb winch on the #WarWagon is capable of such extreme current demands that it can easily damage a battery. Getting that alternator to push out more current by throttling the engine up to 2,500 RPMs helps, but a bigger battery will still make a noticeable improvement. Although, even with a bigger battery I always recommend throttling the engine up first when winching under heavy load. Throttling up when spooling the winch’s cable back onto it’s drum is not needed. The Optima D75/25 has ~33% more cold cranking AMPs over what was installed at factory when GM produced the H3. That ~33% helps to smooth out all the high electrical current demands that things like winching places on the battery.

The dual terminals on the Optima D75/25 battery are a welcomed improvement over the factory setup. The traditional style battery connections posts on top are perfect for H3 Hummer’s factory wiring harness’s positive and ground connections points to the battery. Whereas the terminal screw posts on the front the battery are perfect for the winch along with other high-current electrical components. Lightbars, air compressors, a portable fridge, and other high power electronics all are great on the front battery screw posts. Having the winch, along with other accessories, isolated from the ECU/HVAC/Stereo/etc. is considered ideal. In theory, having the two separated should promote a healthier battery. My best guess is that the increased surface area where the current can flow through because of the multiple battery posts helps distribute the load on the battery by reducing the chance too much current isn’t flowing through one spot. Similar a resistor in a circuit that has too much current and begins to heat up to a point where it approaches failure. Also, sudden spikes in current demand brought on by the winch should be noticed less by the ECU/HVAC/Stereo/etc which could help protect the sensitive electronics.

I doubt I’ll ever agree with why GM put such a small battery in the H3 Hummer. Despite the small battery from the factory, the engineers at GM that designed that battery box in such a way that it is extremely easy to install an Optima D75/25 battery in its place. This is great because having such a quality battery hidden underneath a cheap plastic cover would be shame every time that hood is propped open. In conclusion, I’m very happy with my Red Top Optima D75/25 battery and recommend it over any battery Autozone is going say fits in factory location.


  1. I’m shopping for a new battery for my H3. The Optima D75/25 8042-218 is the yellow top deep cycle version of the red top you have in your picture. Did you recommend the deep cycle Optima for a reason?

    1. Schwarttzy Avatar

      I thought I listed both… I’ll fix that. Either battery will be great, I went with the red because that’s the only battery they had at the Autozone when the factory battery went bad. If battery life was absolutely critical, the yellow top is the way to go. Otherwise, the red top battery is a great improvement over the stock battery.

  2. Did you have to modify or replace the orig battery strap for the Optima?

    1. Schwarttzy Avatar

      I didn’t have to modify the factory battery strap or battery in any way to bolt it into the Hummer. The chunk of plastic that came on the top of the battery was critical for me. I snapped that chunk of plastic on to the bottom of the battery. Which in turn raised the battery up high enough that I was able to secure the battery down using the factory strap without using either of the two battery box components.

      1. Jantony Velazquez-Beveraggi Avatar

        I just replaced my 2009 h3 battery with an Optime Redtop 75/25, like you recommended, and it fit in the factory plastic box…I wonder if mine is different in any way. I can send pics if you would like to see it. Sorry for a 5 year old reply, just recently read this blog while researching a replacement battery for my h3.

        1. Schwarttzy Avatar

          I’m curious too if the size is different than what I have. Pictures and a part number would be greatly appreciated.

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