"I would like to go with a Yamaha 4500kw generator and carry it in my pickup truck bed. The problem I have is I want to put it under a tonneau cover but it is about 6 inches taller than the bed sides. Any suggestions how I could make this work so the generator would be protected from rain and theft?"
It appears the root problem is that the Yamaha 4,500W generator is too large to fit under the OP's tonneau cover. Even so, most suggestions offered (and rejected) seem to be centered around somehow squeezing that specific generator into a box that is too small.
In addition, the OP is resistant to considering smaller generators that can be paralleled; apparently, because they don't provide enough power, or the color is wrong.
I think I have found the solution (which I suspect many of you may have also considered): A Mr. Fusion Home Energy Reactor
-- Ready to process household waste into 1.21 jigawatts of energy!
This unit comes in neutral black and white, with a striking, fire-engine-red locking handle to securely seal radiation safely inside the fusion chamber during fuel conversion. At a compact 18 inches tall, the Mr. Fusion Reactor will easily fit under nearly all tonneau covers. Or, mount it atop the external battery box on your Airstream to be the envy of all SOBs and boondockers. Plus, you'll have enough excess power to light up the entire campground, AND any nearby cities.
Available later this spring, $399.99 (plus shipping).
Sorry, I couldn't resist after seeing the release of this Back to the Future replica... No offense intended; I apologize if the above is taken the wrong way (i.e., other than as amusing reading).
Seriously, from the suggestions that others have offered, there appear to be only a couple of reasonable alternatives:
- Select a single generator with dimensions that will fit under your tonneau cover, and adjust your power needs to fit the wattage available.
- Purchase two smaller generators that will fit, and will provide enough power to meet your needs when connected in parallel.
- Buy a bed cap (camper shell).
- Buy a tarp, some chain and a big padlock.
- Somehow, raise your tonneau cover 6 inches or more in height.
If none of these alternatives are acceptable, then I'm not sure what other viable options are available. I, for one, am stumped...