Next time the battery in a H3 Hummer dies, I recommend getting the Optima Battery 8042-218 D75/25 Red Top or Yellow Top instead of a factory replacement. Although, the Optima D75/25 is much bigger than the factory battery and will not fit inside that plastic box… but who cares. Personally, I think the plastic box is just there to add a distraction from the small battery and the non-GM labeling of the battery. So I ditched that factory hummer plastic box that the battery was hiding in side of, and dropped in a much bigger battery in it’s place. Reason being, the factory battery is under powered and provides only a single set of terminals.
My Warn M-8,000lb winch is capable of such extreme power demands that it can easily damage a battery. The alternator will never be capable of keeping up with the demands either. Throttling the engine of H3 Hummer up to 2,500 RPMs helps out with those demands, but again will not keep up. However a bigger battery is just a better all around solution, just don’t forget to still throttle up when winching. The Optima D75/25 has ~33% more power over the factory battery that GM decided to install. That ~33% more power goes a long way with smoothing out the issues of winching.
The Optima D75/25 battery has the added benefit of having dual terminals ready to go. I use the Traditional style connections posts on top for the H3 Hummer factory wiring harness. As for the side terminal battery screw posts, I have my winch all by it’s lonesome. This is also where I would wire up things like hi powered lights, compressor, portable fridge, and other hi demand electronics. Having the Winch and the ECU, HVAC, Stereo, etc. on separate post from the winch is much better setup. This way the winch isn’t trying to pull excessive power through the same point of contact that the Hummer is trying to run on and charge. Also with the winch and the vehicles electronics further isolated from each other, in theory, this should help maintain a healthier battery.
Considering this is a Hummer, I doubt I’ll ever agree with why GM put such a small battery in vehicle designed for going off-road, or that pointless battery box in there. However, the engineers at GM truly did us true spirited 4×4 enthusiast a solid favor by making it so easy to installing a Optima D75/25 battery in it’s place. Of course, don’t forget the esthetics, because with such a beautiful battery like that, it would be a shame to hide it under plastic box.