Making an electric bicycle (looking for advice)

[BarrysWorld]

thanks Andrew, that IS a great link. I think I will bump it up to 36V. I want to stick with the little motor for size reasons. I'd like to keep the electric part of the bike rather stealthy. I think I can make a pack that will fit in the top portion of the frame. it's one of those ol' Schwinn style frames, so i'll fashion it into a tank of sorts.

[AndrewJ]

It's a great link just because the URL is so easy to remember. I've been looking on there on-and-off for over a month and I never had to bookmark it.

Hmmm, what was that site with the electric scooter parts? electricscooterparts.com? Naaah, couldn't be that, it's too easy...

[NoCO2]

Just so you guys know, this is the math I've been working out, I'll just throw my scratch paper verbatim up here for reference.

HP = v/375 [.00256 x Cd x A x (v^2)] -- that's what I have been working off of.

Assuming a drag coefficient of <= .3 for the trike and the frontal area of the trike I made is 5.04'^2 (6'^2 x .84 as per what it says in the aerodynamics seminar posts) and with a target speed of 45mph, this is the equation.

HP = 45/375[.00256 x .3 x 5.04'^2 x (2025)] -- HP = 4.741 (3538W!!)

Again just for reference in case anyone wishes to see what I did.

[Ryland]

Originally Posted by BarrysWorld

Hey guys, I'm super new to the forums here... and I plan to stick around.
I'm looking for a little advice. I'm trying to do a super inexpensive electric mod to my lowrider bike. I have a motor from an electric scooter I was thinking of using. It's rated at 6A 100W 24VDC. I'm only looking for a little motor assist, as I plan on pedaling all the time too. I had seen on an earlier post that these were good batteries to use http://www.all-battery.com/index.asp...ROD&ProdID=202 ...so, if I bought 20 of those, and made a pack that would be 24v would I be exceeding the amperage of that little motor? Also, I was thinking of using a switch for the power, and only switch it on when I'm up to speed. I don't think the scooters controller would handle the load.

I have those exact batteries, the Tenergy "d" cells built in to a 36volt pack and fitted in copper tubes formed in to a rack, and I'm replacing them because they can't handle the load that my bicycle motor puts on them, they are designed for lower loads, they work great for flashlights, not for bikes, check out some place like Ebikes.ca the "c rate" of the packs is how much of a load you can put on it a 5C 8amp hour 24volt pack can handle 5c times 8 amp hours... 40 amp load... my motor is pretty big and has a 40 amp fuse so I suspect it will never see 40 amp load, so that battery pack would be very safe and work well.

[BarrysWorld]

thank you! I'm sorry those batteries didn't work out for you. I am glad that you shared your misfortune with us... that way others (like me!) won't make that mistake. That triangular 36v pack looks interesting on ebikes. Is that about what I can expect to pay for a decent battery? I'm cool with making my own too, as I've done that in the past for my R/C stuff. I just have to find some good cells

[jjackstone]

NOCO,

Get a Crystalyte 5300 series hub motor. they are rated at 750W, but have been shown to handle in excess of 5KW. They are a bit expensive but worth the money. You'll want a 72v controller for the system. I have the weakest controller made for that voltage and I can still run 30mph if I need to. there are people running them above 50 mph.

Check this link
http://endless-sphere.com/forums/viewforum.php?f=2

Should give a good overview of some of the things going on in the homebrew ebike world.

JJ

[NoCO2]

Thanks for that link jjackstone, the link was great, will definitely be looking into it more as I progress.

This weekend I'm going to start pricing this whole thing out (the trike that is) as I wait to obtain the funds to begin work on the bicycle. Hopefully I will be able to keep the whole thing under $2,000(USD). If I can't keep it under that then I'm going to consider looking for a used motorcycle that I can convert instead. I am also going to start looking for laws that surround home made and kit built automobiles to find out how street legal, if at all the hand built electric trike would be.

[Andyman]

I found an interesting electric powered bicycle on the internet. It looks like a good design but it's a one of a kind project, not a kit. Check this link.

http://www.peltzer.net/ebike/

BASIC SPECS OF V1.5
Scott 24 V DC, 1 hp motor (3 hp max)
Gates Power Grip GT2 belt primary drive
1/2" steel jackshaft on custom shaft ball bearing mount - 3:1 reduction
#35 chain final drive to rear wheel - 2.77:1 reduction
8.44:1 overall gearing gives top speed of about 27 mph
2 x 12V Hawker AGM-type lead acid batteries, 13 Ah each; later replaced by B&B 12v 16Ah batteries (also AGM)
4QD "Scoota 180" speed controller - 180A with regenerative braking
24 V charger charges in 2-5 hours typically
pedal in all 18 speeds
batteries and motor removable in 10 minutes
range 15 miles on the flat depending on pedal assist
weight 85 lbs.

[lovemysan]

Well, I sold my electric bike. I bought a 24v global ebike for $25. I had it running for a little over $100. Top speed was 14mph. It was a fun project but mainly it was a toy. At 90lbs it was too heavy to pedal. Some light training and I could easily outpace it with my regular old trek hybrid. For between $500-1000 I could have upgraded it to make it more usable but I can go everywhere I need to within 3 miles. I felt it would not make economic sense. I also realized the AGM 14.5amp hr pack was horribly heavy. The bike was unpleasant to use for trips longer than 1-2 miles. Range was 6-8 miles using moderate elec assist. I weigh 230lbs, all up weight was 320lbs. I decided to wait a while and let better battery tech mature before I try again. I also bartered a 500w chain drive 36volt 3 wheel scooter for 2 hours work. I was going to do a left side spoke drive on an old coaster brake cruiser. I went as far as getting all the parts and then someone made me an offer for the scooter I couldn't refuse.

[Greenblazer]

check out www.motoredbikes.com it's a forum that is all about bicycle motors.

Later,

Allan Greenblazer