Some questions...
Few quick questions:
Regarding wheel size:
What would you recommend for a vehicle with about 4KW of power? It's not even close to finished yet so I have no idea how fast it will go (but I'm assuming pretty fast). 9 or 13 inch? I'm thinking 13 inch would be safer but I've seen some 9 in. wheels in a store around here I like.
Regarding battery pack:
Don't even suggest lithium because there's no way I can afford a suitable pack. Even NiMH is way out of my price range. So basically I'm going with SLA. Thing is, what would be a good brand? I've heard good things about B.B. (I think that's what it was) batteries but I have a new PowerSonic 12v 35AH battery sitting in my garage left over from...something or other...that I would like to use. Unless I find out it's a total POS I'll just go buy 3 more. Would this be a good idea?
Regarding power train:
This is my big problem. Not even the slightest on what to use. I'm gonna need some low end torque to get this thing out of a standstill. It's probably going to end up weighing over 250 lbs. Then add my 175+ onto that and using a single gear ratio is completely out of the question. I'd like a decent top speed, thank you. The only thing I could think of that might work is the rear sprocket cassette of a mountain bike. However, I don't know if that will hold up to the kind of torque and/or RPM I would need it to.
Other than that, the only thing I could think of would be to modify a torque converter (I think that's what I'm looking for) meant for a go-kart. Could I even do that?
If anyone could give me their thoughts...
Yeah, I know. When the pack is finished it will probably consist of 8 batteries x 12V x35 AH = 3360 WHrs. They weigh about 25 lbs. apeice (according to my bathroom scale, which is off by I don't know how much) so that's going to be a 200 lbs. of battery. I'm hoping they will last at least 20 min. at flat out. Maybe more, since the amp rate will be only just above 1C.
As far as gearing is going - a single sprocket is not out of the question (unless you want it to be for some other reason). Track down El Ninja by John Bidwell and numerous other motorcycle conversions. They often use a single fixed chain and sprocket. El Ninja uses a 16 tooth front and 72 tooth rear. On my CB-750 I'm considering 10, 11 or 12 front (TBD) and using the original 48 rear. This won't give blistering accel (!) but should be good for a top speed of 60+ mph. These bikes are considerably heavier than what you describe.
What are you aiming for? Do you favor accel over top end or vice versa?
For sure a transmission will help - after the CB-750 I'm considering a maxi-scooter conversion and I'll attempt to use the CVT from the original bike. Don't know if a CVT from a small gas scooter would help you or not.
50% capacity drop at 1C!? Peh. What about 1/2C? I probably won't run it much higher than that anyway.
Actually, I'd really like some nice acceleration and best possible top, so I'm going to go with the transmission, since as far as I can tell it would simply be a matter of disabling whatever mechanism makes it kick in a a certain RPM. Anyone wanna recommend a good one? I'm looking at that torque-a-verter thing...
I'm REALLY hoping I can grab me ahold of one of them eteks I've heard such good things about.
...
I think I'll sell that battery. I'm eager to see how those second-gen supercaps turn out in a couple of years (supposedly TWICE the capacity of LiPo, and, seeing how it IS a capacitor, likely an unbelievable discharge rate!).
Thanks for that link.
Hmmm, 25AH @ 1C...
Yeah, I'm ditching that battery. Maybe I can sell it on eBay after lead prices go up further (curses) and make a profit...
I'm thinking an Alltrax would be well suited to an etek. Can anyone here attest to that?
P.S. Why does it keep going "[i]" everytime I try to make a capital "i"?
Yes, Alltrax and brushed Etek is a common combination. You might also check out Perm 132 instead of Etek it offers a greater power output. Check out http://electricmotorsport.com for details - they sell some packages based around these components. Not suggesting you do or don't buy from them it's just a useful starting point.
Yeah, that i / I thing has got me before - but not all the time. It's weIrd...
Yeah, I knew about the PERM-132, but I could get nearly two Eteks for as much as that thing tends to sell for(which I had kinda half planned on anyway).
Interesting, but not for me. I want to use one of the higher rated controllers in case I ever decide to use a different motor.
The going rate for the Etek seems to be +/- $500. Incedentally, anyone know where to get one for cheap? If not I'll see what eBay has to offer.
P.S. Why does it keep going "[i]" everytime I try to make a capital "i"?
It's because you probably hit "ctrl-shift-i". Hit it again and the behavior goes away.
I have been looking for an electric bike for over a year now, I have test ridden many different electric bikes, done research on kits etc... The bike I was most impressed with is the Ecobike Elegance 36 model. I have test ridden the bike several times since there are several bike shops in my area that sell Ecobikes. Before I buy I just want to be sure that I am buying the right bike for me, any input or advise would be greatly appreciated! Does anyone own one of these bikes? Has anyone heard anything good or bad about Ecobike? The Elegance 36 really impressed me, it has pedal assist, throttle only, and traditional riding modes. 10ah 36V li ion battery, 26" wheels, very comfortable to ride. I am not really a technical person so please if anyone can advise me about this bike it would help me out alot, I would like to purchase an electric bike soon now that the weather is perfect for riding!!!
Thanks!
Wow! You'll be running with the big dogs!
For some perspective, have a look at:
http://www.austinev.org/evalbum/
4000W will eat a lot of amps, which means a lot of lead or short range.
It'll be fun, though.
MarkF