I just got my BMC V3 motor from Ilia aka ebikes_sf for a good price
without the ridiculous markups I have come to associate with other vendors BMC products. I've been wanting to build one of these 1000w motors since I first saw a youtube of one advertised as the 'black lightening'. I have heard impressive reports of speed, torque, and effeciency at low voltages (like 33mph@36v
), and I look forward to discovering that for myself. Then I look forward to pushing those limits, maybe as far as 120v with a Kelly Controller.
As a carryover from my ICE days, I am a big believer in stealth. Big loud motors attract attention, which is fine for show, but not so much when you want to push the limits. This compact motor should help with stealth, and I hope it is not too much noisier than hub motors. It comes in gloss black, and I have a spare gloss black Tidalforce IO Cruiser frame, so I decided to go for a 'blackout' bike, trying to make everything possible gloss black. I also wanted a WIDE rim, to put the best possible patch on the ground, and make the most of the 2.5" Maxxis Hookworms that have become my standard. Ilya suggested the Alex DX32 downhill rim, a whopping 39mm wide, a bit heavy for some downhillers but built like a tank making it a great choice for ebikes. In the pics below, the flash makes some of the gloss black spokes look silver, but they are black. I have a few questions for wheel-builders.
Ilia is just lacing wheels to help people out, he isn't a full-time wheel builder. I noticed that he missed the 'key' spoke and the spokes 'V' right where the air valve hits, instead of being open for easy access. I also noticed that onh all of my other hub motors, where the spokes cross they are bent over each other, and I thought that had something to do with distrbuting tension and making the wheel stronger. In this case, the spokes are not bent over each other at the cross, there is actually a gap between them. Given that I intend to subject this motor to some pretty heavy stresses, should I re-lace the wheel so that the spokes cross? If I do so, will I need longer spokes?
I wanted to match the front wheel to the rear wheel, so Ilia supplied me with another Alex DX32 rim. I like the Rock Shox Boxxer fork I used on my xtracycle, so I bought another one used on ebay, with black lowers. It was cheap but It needs a rebuild, and I think I will pirate the black crowns from the xtracycle to keep to the blackout theme (anyone know where I can source a cheap uncut steerer tube/crown for Boxxers?). Since the Boxxer uses a 20mm-through-axle wheel, I sourced a 20mmAdventure Components Aircooler hub to complete the picture. Now I j[img]ust need gloss black spokes, and to rebuild the fork, and I'll have a front end.
For the meantime, I'm going to use the stock forks and experiment with this motor to see what it can do. I'll grab one of my spare 72v LiFe packs and use it to test these controllers with the hub - a generic Crystalyte 72v25a analog controller to start. This should supply close to 2kw to the this 1kw motor, and we'll see what's what.
Then I'll try one of the 'knuckles' 72v50a infineons I have had sitting around, and see how it handles 4kw. I read some folks were having problems with these heating up on V3s, and I wonder if it was just the resistance head from the phase wires. I'll clip the skinny OEM phase wires on the motor as short as I dare, and solder on some 8gau leads instead. I'll still have the measly 14gau wires going into the hub, but they will be a very short run, and I hope the 8gau will help bleed off some of the heat from them.
If the motor still feels strong, and the frame feels like it is handling it well, and I am feeling daring, I'll move on to the Kelly, and maybe up to 120v. I might recruit an experienced motorcycle rider with protective gear and a full-face helmet to volunteer for 120v test runs. I am very curious to see what this motor can do at 120v, but 45mph made me nervous and this promises to go much faster.
Please forgive the shrunken pics that get stuck at the end: