Setting up Project 600-HP 7.3L with a 300-amp Alternator from Mean Green
Unless you’re one of the few who actually has the “Ambulance Package” that door stickers always warn us about, your charging system isn’t designed to handle many more electronic devices than what’s already installed in the truck from the factory. Adding an aftermarket stereo with subs? Some LED lights? Or maybe a winch? The OEM alternator may be able to handle one or two of those things, but not all of them, and definitely not for very long. A good high-output alternator and set of batteries is a must for any vehicle with additional electronic accessories.

Getting the stock 105-amp unit out is extremely simple. Loosen and remove the belt with a breaker bar, pull three bolts, disconnect the positive charge wire and one other electrical connection, and it’s free. All in all, it’s less than a five-minute removal.

Project 600-HP 7.3L sees a ton of hours being in the middle of the California desert. Participating in activities ranging from camping, to being a support rig for construction, to off-road racing, photo shoots, and much more. The 17-year-old truck has a 5K inverter used to power whatever we need it to, and trust us, every bit of the 5K rating often gets used. On top of the inverter, the truck has more than 1,000 watts of stereo equipment and a large on-board air system, plus a multitude of aftermarket lights and other low-draw accessories. The only way we could get the inverter to work for long periods of time was to shut any other large load off and run the truck at an elevated 1,500-rpm idle. Even then we were going through batteries every 18 months or so.

While an alternator of this size is extreme overkill for most, for our needs we decided to go with a massive 300-amp unit from Mean Green. Mean Green offers more “sane” units for those with lesser needs than ours, and they install in much less time too. Our 300-amp Mean Green alternator offers nearly 300% more power than the stock 105-amp unit. On top of all the parts that make it do its thing, it’s built with a tool steel rotor shaft, double-sealed bearings, and high-temp-rated insulation, all lending to extreme durability. In the end, our install took less than 45 minutes, with the added time dedicated to beefing up the wires to the battery. A 200-amp install is a quick swap and shouldn’t take much more than 5 minutes.

Side by side, stock vs. Mean Green. The Mean Green 300-amp alternator is noticeably larger and more robust.
Looking at the backs of the two units, the only real difference (other than everything being bigger) is the addition of a ground stud (more on that later).
More output means bigger wires are needed to carry it. So this 12V+ terminal is larger than the one on the factory alternator. It is, however, in the stock location so the factory wire can still be hooked up if need be.
The Mean Green unit uses a 0.25-inch smaller pulley, which means the alternator spins just a bit faster than the factory unit. The instructions note that some may need a different belt or idler pulley to make up for the differently sized alternator pulley, but we had no issues whatsoever.
Fastening the alternator was simple; once it was snugged down, we reattached the belt and moved on to wiring.


To take full advantage of the alternator’s added output we needed to upgrade the battery wires. We ended up using some 2-gauge wire for both connections. On the ground side we used two wires, one straight from the alternator to the battery and another from the battery to the frame. On the positive side we went straight from the alternator to the driver-side battery.
Four months later and 6,000 more miles on the clock, we’re happy to report we’ve had zero issues, all accessories run perfectly and we even noticed the truck starts much easier (we’re sure due to the batteries staying at peak charge). We’ve never had this kind of peace of mind immediately shutting the truck off after running the inverter or on-board air system. We always kept it running for a bit just to make sure the batteries got a good charge. That’s no longer the case—we’ve got complete confidence in the truck’s electrical system now.


Mean Green Industries

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