~20-25mph. Dude, 48V on this thing is the best thing EVAR.
Generic pic. Will take more when I get a proper camera.
UPDATE: Finally got around to installing another battery. The NiCds I was going to use were proving too bothersome, so I got another matching SLA battery and stuffed it in the box. There is absolutely NO room left. I even had to move the controller (which is tiny) outside of the battery case. The aluminum it's encased in is incredibly durable (I had to bend the flange on the side, and had a hell of a time with it. I had to resort to a large hammer, and even that proved difficult). The fit is so tight, that the wires and connectors barely have any room; I had to lay them flat to get the deck on.
In addition, I had to break off the power and light switches. They protruded a little way into the battery case, and the batteries pressed up so hard against them they snapped. It wasn't too problematic, however. By soldering the wires of the switch together, I was able to make a key that I could pop into the controller.
It was all worth the trouble, though. The extra speed is really awesome.
My next task is to check the chip and see if it can take 48V. If it can, then I will replace the FETs and caps. I'll add a fourth battery externally that I can detach if I want. That or a small NiCd booster pack.
I did note something interesting during my rides and I think I'll want to fix it. The wheels get noticeably warm when riding. While this is sort of cool ("Hey, my skateboard is fast enough to f*** up the wheels!"), it's also something of a flaw ("Dammit, my skateboard is fast enough to f*** up the wheels."). Oh well. Guess I'll just have to get new ones when they wear out. Not really a problem, since they are just kick scooter wheels (think Razor).
UPDATE 2: Well, I got bored waiting for my ebike parts to get here, so I thought I'd up the voltage again. 4 batts don't even come close to fitting, so I just took them all out and supertaped them together into a brick. They go in a backpack, along with the controller.
I've also added a throttle. It's not a proper throttle, just a half-twist hall throttle meant for a bike. It works well enough. I can grip both parts of it with one hand if I just want to cruise at a set speed.
The speed is incomparable to all but the best of boards. You can't buy a 20+mph board (new) for under $500, and mine should be around 24mph or so. I'll get to testing the exact speed later. In total, I think there about $170 bucks of parts (including shipping) in this board. Totally worth it. I think I'm pretty much done with this, since I don't want to push the stock motor any harder. I won't have a new board for quite some time, but it will be completely custom, built by hand from raw metal, and likely a hub motor in the rear. Speed goal is 30+mph.
Californians don't need heaters. Air conditioning, son.
Yi-Yun 36V YK-40 running at 48V
I temporarily parallel up the batts and charge them with a Vector on 6A (1.5A per batt).
Miles as an EV:
Pfft, I don't keep track.
3 super bright LED headlights. It's got tail lights, too. (I had to deactivate them for the mod, though.)
10 lbs. plus about 15lbs of batts in the backpack.
Conversion time and cost:
$36 from eBay, plus two more batteries.