Electric Bikes - Electric Folding Bicycle
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04-30-08, 10:06 AM
I have recently taken an interest in electric bicycles. I have a citizen folding bicycle that I got last year and was wondering what I would need to do to make it an electric bicycle. It has 20" wheels. I can post a picture of it if need be. I would like to be able to go at least 30miles on a charge. Any recommendations? Also, I just got out of college and have no money so the cheaper the better.
04-30-08, 04:45 PM
Um..... that's a very tall order chickfilafan. The simplest and cheapest setup would be a hub motor with SLA batteries, - only I don't think that you'll be able to get anything like 30 miles on a charge with such a system. It seems to me at least, that the more lightweight and hi-tech the system the more you have to pay for it. There's been a fair bit of debate here in this forum about alternative battery systems that are much lighter than SLAs, but lightness and more range makes for greater financial angst which is why I've stuck with SLAs myself.
04-30-08, 10:29 PM
Hmm... is there anything that would go that far for a 26" bike? I am willing to spend $500-$700. Also, I should probably just start another thread for this but what are the pros and cons between a front wheel hub motor and a rear wheel hub motor?
The simplest and cheapest setup would be a hub motor with SLA batteries, - only I don't think that you'll be able to get anything like 30 miles on a charge with such a system.
If you buy a Lithium Iron Phosphate battery like mine (24V 10Ah, costs $200 or so on e-bay) you can get a 6 pound battery that will give you 30 miles of range if you provide about 50 percent of the power yourself through the pedals. more like 15 miles if you don't pedal. But then you need a motor to go with it, which will cost extra. For 30 miles to the charge, SLA batteries are probably a terrible choice.
Also, if you need inexpensive&long range, don't plan for high speed - to get 30 miles per charge out of a little battery like mine you need to go about 18 miles per hour or less.
05-01-08, 08:20 AM
I'm afraid $500-$700 might only get you lightweight high capacity batteries and charger needed for your desired distance. Do YouTube search for "nano Brompton" for very clean example of a practical folder.
check electricrider.com for hub kits. The main problem with folding bikes seems to be fork dimensions. They're often very narrow which might not accommodate hub motors and may need to be bent and/or reformed (safely) to fit a motor in the forks.
20"-26" really doesn't matter in the eBike world IMO. Main difference is ride quality. Bigger wheels roll over bigger holes with less trouble. Motor makes up for pedaling resistance. Speaking of pedaling - 3spd internal gear is about all I think an eBike needs. Most folks that install motors on 21 speed bikes find they only use 3-5 gears with a motor.
Another angle is to look for used eBikes with bad batteries on Craigslist and local classifieds, garage sales, etc. They can go cheap and most of them made in the past few years are good enough motor/controllers saddled with SLA or NiMh that no longer hold a charge. I've bought a couple very cheap that way - scavenged the components, added my own batteries. Majority of people don't have a clue what to do when the batteries die - and the batteries always die!
Once you go with a sensible motor drive I doubt you'll regret it.
Front or rear? Folders are very hard to fit rear hub motors. Once again the narrowness of the fork (front or rear) comes into play. I like the simplicity of front hubs for a cheap, quick fitting of motor to bike it's hard to beat. Some folks don't like how front hubs feel - especially if it spins on slick surfaces. Or on steep hills you may need to stand up and lean on the frontend to keep the tire in contact with the road surface.
The people who dig rear drive hub motors seem to be more interested in electric motorcycles than eBikes. I suppose if you want a couple horsepower motor to cruise at 30mph or more the rear will be the best place to put it. I don't care for the weight distribution of that choice - but a powerful motor will spin on the front. Mild motor - not so much if any.
05-02-08, 12:56 AM
Maybe you could pick up some ideas from the model mentioned in the other "Electric Folding Bike" thread.
(scroll halfway down the page.)
I believe a small folder like the citizen will wear you out after a week or two. Based on your budget and 30 (60 ?) miles a day I believe you will have better luck with the 26" bike with a rack-mounted, 2 cycle, smoke and smog belching gas engine.
Don't say no until you look at http://www.motoredbikes.com/forumdisplay.php?f=86 (rack mount section) and GEBE kits http://www.bikeengines.com/index.htm
Last time I looked you could buy a GEBE kit for $650 +/-, and buy $3 in gas and drive all week. You'll have to replace the bike before the engine wears out. But I believe you will need $1400-1800 for electric comps. and will replace the batts in one or two years.
edit: If you have mney left over spring for a new bike with shock absorbers and a comfort seat.
Save the electric set-up for your next pay raise.
05-23-08, 05:15 PM
Scroll to see Dahon folding bikes. The BionX is a very good and livable solution.
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