When I worked at the golf course, the carts for the duffers were all gas-powered, but we also had electric utility carts... mine was a Yamaha. Nice cart, and fairly quick too, but I kept it plugged in whenever it was not in use. I think your idea to rig up a panel on the roof was brilliant, why NOT use that space? I enjoy reading this thread because I'm a gearhead at heart, and I like seeing folks make mods suited to their specific needs.
I once modded TF out of an old Honda Z50, the thing had a Piranha 140cc motor, extended fork legs with stiffer springs, burly aftermarket shocks, nice knobbies, gold chain, custom seat, MX bars, translucent Clarke Racing mini-thumper tank (to check fuel level at a glance), it even had a ridiculously-over-the-top carbon fiber can on the aftermarket exhaust pipe, lol. I still kick myself on occasion for selling that bike, but I needed money at the time... and I have some good memories.
I'll have to dig up a video link or two here in a bit, just so you can see what I mean... it was certainly the most unconventional Honda Z50 I've ever seen, and with the 140cc Piranha motor it was a beast on the trail, lol. Really just a miniature bad@$$ dirt bike, I took it into the field with me and had heaps of fun riding that bad boy... now somebody else is riding it, and I hope that person is having as much fun as I did back when I had that little offroad rocket, lol.
Ya know, before I installed a Curt hitch and cargo carrier on 'The Mighty Camry' to haul the bike, I would simply tarp the back seat and place the bike inside the cabin, lol. It just barely fit with the MX bars, but it fit, even though I scratched up the paint a bit in the door frame on the loading side, lol. I'd pull up to a trailhead where a few other riders were present, and they'd all gravitate toward the bike once I unloaded it. Guys with big ol' KTM thumpers would sit on it and exclaim:
"I HAVE GOT TO GET ONE OF THESE!!!"
Lol... I always thought that was pretty funny. Lemme go dig up a video link for ya, aye? You'll get a kick out of it...
Edit: Okay, I found one video that gives ya a pretty close look at the bike, even though I'm not actually riding it, lol. Forgot to mention that bad@$$ aluminum swingarm earlier, that set me back about $200, lol. Swapped it out in my living room while watching football years ago, lol... anyway, you'll get a kick out of the bike, check out that ridiculous carbon fiber can, aye? That Clarke Racing mini-thumper desert tank also set me back something like $200, but it was totally worth it.
The Beast!!!
P.S. Those are gloves or whatever resting on the bars... I'd stop in a shady spot to grab a beer out of my backpack, lol. Looking at the video again, I see a Coors stubby in a cooler cup resting on the exhaust, lol.