So, reading more about recumbent, I think I now understand that a smaller front with a larger back will handle better, though it surprised me because I normally think 20" is a pretty nice situation for motors, and that the only downside to my 20" bike is that the front sometimes is more wobbly.
Back to the original thread, I just happened upon an evalbum giant revivehttp://www.evalbum.com/3865
That's actually not a super build, but I guess my point would be that there are quite a few giant revives to look at for ideas.
With already having the bike, a $1000 budget, 30-35mph, 20 mile range, you're almost there, but one of the three I think would need to give way a little bit. Or, perhaps you can wait for very good deals on each component.
But let's price some things.
MAC 1000W kit, $365. Running this kit at 48v will give you your desired speed, and would be more like 1350watts.
Shipping for said kit: ~$50 if you go by sea. Not sure what otherwise. I'm guessing based on my ~$35 dollar cost for my simple 20" mac motor kit.
Random tidbits of wiring ~$20.
This leaves you with $565 dollars left. I suppose that's where the 52v, 11.5ah battery pack idea comes from. Whoops. I should have just listened to what you already asked about. It's not bad. I'm not sure that it will get you quite 20 miles though. That would be asking for (52*11.5 =598whs*80%[to not fully discharge]=478wh/20miles = 24wh/mi. I think it's too optimistic, for the high losses you will get at the higher speeds. Are you willing to compromise that aspect [range] of the ride? If it's a commute, your easiest bet is to work hard on making charging at work available.
Cell man's very well made battery will probably be cheaper than the (hu)man-hours of putting one together yourself, but you also have that option. The 20ah a123 crew has been buying them for, eh?, $25/ea all things considered? I hope I'm not wrong, but that's really cheap for a123. 17*25 = $425, + ??$50?? for the pieces involved in connectors, $55 for a 16s 30a constant BMS, and you have...only $30 or so to buy a charger and figure how how/where to mount the batteries. This is the only thing I can think of to circumvent the range/speed/money equation. I guess that makes it a range/speed/money/time equation.
Don't forget at some point that you'll probably need torque arms at that power.
^I think I wrote a lot, but didn't say much.
New to endless-sphere? Notice a lot of signatures recommending Ebike.ca? That's because it's the best place for a quality and manageable, (but still 'real'), first build. Justin is a solid supporter of electric bike development, and a good source of equipment.
My hat off a thousand times to the green people that effectively run this forum. The ES Mods are superb.