Electric Bike

[Sheena Kean]

I have had an electric bike for about a year. Its great takes all the effort out of cycling up hills. It gets me to my work 1 1/2 miles away in 10 minutes.It needs charging about once a week (using our green energy). it is quite heavy I don't like going down steep hills as it tends to run away with you. But it is a definite thumbs up, and saves on the diesel I would use if driving my car.

Sheena Kean:)

[Joe Blake]

Hi Sheena,

Welcome to the Forum.

As you'll probably find out if you haven't already, I'm an e-bike user/builder.

In regards to the "running away" going down hill, I suppose I should ask is this a "store bought" or "home brew" bike? I've noticed many home brews and even some store bought machines are just standard bicycle frames fitted with standard bicycle brakes and wheel(s), which of course aren't capable of handling either the extra speed or mass from the motor and batteries.

Although my trike has drum brakes, this morning I was going down one of the steep hills near my house when I came up behind a train of cars behind a VERY slow driver, doing roughly 40 km/h in a 60 km/h zone. It was close to a kilometre down and by the end of the descent my brakes were so hot that water just boiled off them straight away. I should have pulled over to the side and stopped, except it's a very sinuous road with no space on the side to stop.

If your own brakes are standard bicycle brakes, you may consider fitting tandem brakes which by their very nature are designed for handling heavier loads (ie TWO people instead of one). Not only will they have greater stopping power, but they will handle the heat better. (But then of course you may have to get a stronger wheel with thicker spokes.)

Anyway, regardless, glad to see that it's working for you and your green machine is doin' the job.

Joe

[Sheena Kean]

Hi Joe

My bike is a store bought one it does have heavier than usual bike brakes. we do have 2 seriously steep hills wih sharp corners half way down or up depending which way your going. it does tend to skid when going down, however it hasn't put me off, it is also great off road.

Sheena

[Joe Blake]

Hi Sheena,

Just returning to the skidding. A couple of questions related to your cycling experience rather than electrics in general. How long have you been cycling? Do you ride (or have you ridden) a motorcycle previously? (Please excuse me if I'm preaching to the converted .:bigsmile:) Why I ask is that braking technique on bicycles and motorcycles is different to that of cars in that the braking on a car tends (or tended) to be pretty simply distributed and uses only the footpedal, whereas bikes generally have a lever for each brake, front and rear. As the brakes on a bike are applied the mass/inertia tends to transfer to the front wheel, which makes the rear wheel lighter hence more prone to locking up. I've found a good trick to use the front brake first applying it progressively, and use the rear brake to keep the rear end "in line". Also try to keep your weight on the seat and hence on the back wheel.

The next question relates to the electric motor. Where is it mounted? Is it a hub motor or does it operate via the chain? Does it have regenerative braking? If you're not familiar with this, some electric motors have a function that when the user closes the throttle the motor acts as a generator, retrieving some of the energy to recharge the batteries and extend the range of the vehicle. But this also has the effect of causing the motor to act as a brake. (Since you seem to ride this bike a bit, you probably would have noticed anyway if it did this, but thought I'd ask on the off chance.)

Joe

[Randy Reed]

Hi, I hope you don't mind a noob question.

I've been thinking about an electric bike (I live in a small town - mostly flat) but I don't know where to start. Can you recommend some good resources for info. I'm not a motorcyle rider, so I don't have any habits to break.

Basically, I'm starting from zero, as far as what I know.

Thanks

[Joe Blake]

Hi Randy,

Welcome to the forum. The word "electric bike" means so many things to so many people. To some people it's seen as a replacement for a car/motorcycle with the same performance but without the high cost. Ie they'd like to be able to zip down the freeway with the traffic, cover a hundred or more kilometres without having to refuel. To some others, it's a means of doing the local shopping, not breaking speed limits, but covering 5-20 km, every couple of days, without getting hot and sweaty. And for people like myself, I see it as an adjunct to my pedal power, just to get me up the hills a bit easier, or to tote the trailer with a fortnight's shopping.

Each of these would have a different starting point. If you wanted the first (and it doesn't sound like you do) then you'd be dreaming, because this sort of performance can be had, but at a great cost.

The other two ideas can be achieved by either buying an already assembled e-bike from a shop as Sheena has done. Any information I could give you on this would be pretty irrelevant since I live in Australia and we have different shopping chains, different cost structures, different laws regarding power etc.

Check your local traffic department or road safety people and see what you're allowed to have before the machine becomes classed as a "motor vehicle" and needs to be registered and the rider needs a licence etc.

Try and steer clear of buying "El Cheapo Brand X" machinery because the lower price indicates a lower quality, hence a shorter life and lower performance, which can leave you with a bad experience. I've seen reputable/ quality machines on sale locally which look like they would do the shopping gig comfortably and cheaply. It's not just the motor to be concerned about. The frame and wheels should be strong enough to carry the extra weight of motor and batteries, the brakes should be capable of consistently and safely stopping the bike from its top speed, (bearing in mind the extra mass) and I would tend to look more favourably on a system which has the motor mounted inside the rear hub. I find front wheel drive a wee bit twitchy, but that's probably just a lack of experience on my part.

I would avoid anything which mounts the motor on/in the frame and puts the extra drive through the chain/ gears. Two reasons. If the power system is mounted on a "standard" bicycle frame, ie one which doesn't normally have assistance, then you can be looking at the possibility of the extra torque of rider AND motor combined twisting the frame out of alignment and/or wearing/ destroying the drive train ie chain and sprockets, none of which are designed for that consistent load. Secondly, if you DO get a machine which is specifically designed and built to have the motor drive through the chain/ gears, then this will more than likely involve extra expense because of the heavy duty nature of the chains, frames, sprockets etc, and possible difficulties with finding replacements.

This link takes you to my own little project:

http://www.wired.com/autopia/2008/09/solar-trikey-ma/

I'd suggest you look towards 24/36 volts, simply because I think the motors run under less strain that way, but it fusses with the way of mounting batteries.

At the moment I'd say lead acid batteries are still the best option taking weight/ performance/ cost into the mix, but the technology is still evolving, luckily, and the balance may tend towards other types, NiMH or Lithium ion or whatever.

The Heinzemann motor which I use comes complete with everything, all the controllers, wiring, etc, ready to be mounted and has been very reliable. It's a bit more expensive perhaps than others, but this is made up for in the sophistication and reliability. (eg it has a built in thermistor protection, so if the motor overheats, it shuts down before damage can be done. I've used this (unintentionally) once, and I suspect it saved me from a big expense.)

There are several specialist fora, such as this one

http://www.bikeforums.net/forumdisplay.php?f=258

which go into much more detail, but I've found the majority of people seem to be trying to get down the performance road which I'm not into. Plus you seem to get the abusive, tetchy people who seem to think an internet forum is a place to vent their anger on any topic (which, fortunately, this Greenpower forum is not).

Hope that helps you a bit.

Joe

[Randy Reed]

Joe,

Thanks for the great info.

Although I haven't ruled it out, I probably won't buy one pre-built. I have a background and degree in electronics and am somewhat of a garage tinkerer. I started down the road converting an old golfcart by planning to lengthen the frame, increase the power, build a fiberglass body and create a small electric sportscar for in town here. However the project was a bit over my level of expertise (welding and all).

I had decided to scale back to a bike, most likely pedal assisted. I took a look at your project and was knocked out! I hadn't considered a trike. It makes so much more sense than a two-wheeler - on many levels. I don't think I'll need to add solar assist. This town is less than 3 miles from end to end and pretty much flat. The fastest speed limit is 40mph, but only on one small stretch. We're on the edge of the mountains, but I will most likely be using the bike in town.

You've really got me thinking. Thanks. I have a lot more options to think over. I guess it's time to do some serious research.

Btw, I skimmed though some of the comments. Don't let the insult mongers get to you. I'm 57 and in the same shape. I get around just fine and I'll bet you could pedal those guys into the ground.

Again, thanks for the great response,

Randy

[Joe Blake]

Thanks Randy.

Keep us up to date on how you go with it. Be interested to see how you fare.

Joe

[Angie Joe]

great all of you members ...its so fare and useful talking and i enjoyed it .I also try it on my bike .

[Joe Blake]

Since this thread has been revived, I'll just update on my own experiences.

I added a fairing to the smaller ("Spider Trike") but I have to say the difference between faired and unfaired is minimal. (You can see the second trike ("Proud Mary") sitting on the patio just behind the PV array on the Spidey.)

http://i82.photobucket.com/albums/j245/saxeharp/trike/P2190002_zps1a0aa0a0.jpg (http://s82.photobucket.com/user/saxeharp/media/trike/P2190002_zps1a0aa0a0.jpg.html)

I think this is mainly because the fairing only comes into its own at speeds higher than I normally travel at. On "Spider Trike" the electric motor only takes me up to about 16-17 km/h (without pedaling) but I can reach 35 km/h by pedal power, although this is a fairly difficult speed to maintain given that the motor and batteries at this speed are just extra mass - the whole outfit weighs 34 kg.

One reason I fitted the fairing was because of the increasing interest in velomobiles

http://upload.wikimedia.org/wikipedia/commons/e/e9/Velomobile-decapotable-rouge2.jpg

https://encrypted-tbn2.gstatic.com/images?q=tbn:ANd9GcSU8KcvSaR_9HolQebZB7g_VfH1eR6TF 4WP6pPCJ82KeQA57ChxMg

which, while having significantly better performance than "normal" bicycles, can be fitted with electric motors to assist.

Watching this video inspired me to buy the fairing. It's fairly lengthy (40+ minutes) but I love watching it.

http://www.youtube.com/watch?feature=player_embedded&v=z0BZl2O1Nxs

Joe

[Rob Beckers]

Joe, they're all on the wrong side of the road! :eek:

Those things are fast! Neat to see too how they barrel past the regular bikes on downhills and keep going for a while on the uphills too. Guess that between the higher mass and the lower air friction the energy loss is much slower vs. a regular bike.

I think you already get much of the benefit with your bike, even without all the fairings, just by being reclined. Much lower frontal area and drag that way. You'd have to go really fast to get additional benefit out of the fairing (of course, doing 36 km/h average on a 200+ km course like these guys is fast!).

-RoB-