Okay, to make a short story long, I want to electrify my 1994 Gold Rush Replica recumbent bike. There are over 50,000 miles on my mistress and she and I used to spend a whole lot more time together. Alas, I'm getting old. The 20-mile one-way commute to work (with the killer hill the last three miles) is just not something I can do two to four times a week anymore. One major problem I foresee is that adding some thirty pounds will make the bike less enjoyable to ride for fun. Therefore, I'd like to be able to de-electrify it easily. From lurking around at various sites, I have a preliminary plan in mind. Any and all comments, suggestions, criticism, etc. are much appreciated. Here's the idea:
Get a Crystalyte Phoenix 48-volt motor for the 20" front wheel. (There are at least two sites that offer them.) Add to that a 48-volt lithium iron phosphate battery with 12 amp hours. 16 or 20 amp hours would be nice but add more weight (and cost) and I think the 12 amp hours will be sufficient since I still want to pedal quite a bit. By putting the motor on the front wheel, I hope to be able to quickly move back and forth between the new motorized front wheel and the old non-motorized front wheel.
So, whaddya' all think about this plan? The price should be somewhere around $1,500. That's bumping up pretty close to what I could pay for a used Honda Rebel 250cc motorcycle. The Rebel would be much more fun than driving the stupid car but offers no opportunity for exercise. I'm not married to the Crystalyte but it does seem to be a favorite. I definitely think the lithium battery is worth the extra cost.
Many Thanks in Advance!
sounds like a good plan.
though i wouldnt bother with making the wheel with the hub motor removable.
they arent all that heavy.
the real weight will be in the battery pack.
im guessing your recumbent is a reverse tadpole?
Matt
Daily Ride:
2007 Vectrix, modified with 42 x Thundersky 60Ah in July 2010. Done 194'000km
I agree your plan is good, and disagree with antiscab about removability. I just bought a crystalyte motor and it's heavy enough to want to remove it when not using it as you're suggesting. Fortunately for you, this is your bike and you can decide for yourself which way you want to go ;-) once you get the motor in hand and decide for yourself what fits you.
But there are other motors that could work well. Go to http://electric-bikes.com and take a gander at the mid-drive system they have described there. Or look at the Cyclone system. Both if I understand right do good quality freewheeling such that the motor doesn't degrade pedaling when not in use. Some motors do put a drag on the bike when the motor isn't being used.
It would be more convenient to not have to swap wheels. Obviously. So long as leaving the motor on the bike doesn't degrade the bike by much.
As for the battery, LiFePO4 is a great idea but just make sure to find one with a high enough discharge rate to support the crystalyte motor. That's a powerful motor ...
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
The Gold Rush is a two-wheeled recumbent (www.easyracers.com)
The mid-drive systems look great but I doubt if it would be easy to create one that could be easily swapped off and on.
Right, I don't think it is possible to have a mid-drive that can come right off. The cyclone for example would require replacing the bottom bracket. BUT .. what I was getting at is a) I believe the mid drive is very light weight and wouldn't impede the cycling experience, and b) assuming the drive freewheels properly you won't notice any drag due to the motor still being in the drive train
- David Herron, The Long Tail Pipe, davidherron.com, 7gen.com, What is Reiki
Ah, got it. The mid-drive is pretty light and would permanently only add about 10 to 15 pounds to the bike -- about as much as I could afford to lose from my gut! The mid-drive freewheel is also very cool. My cousin, the avid motorcycle rider and large diesel engine mechanic, liked the mid-drive setup better. The problem with the mid-drive for the Easy Racer Gold Rush is attaching it. The mid-drive system I really like (from www.ecospeed.com in Portland) requires a $700 package to attach the mid-drive to the Gold Rush! I could easily buy a used 'bent, say a EZ-Sport (the much less costly and less sophisticated version of the Gold Rush) for that much. Then I would have two recumbents, one for commuting and one for fun. This would normally be very cool, indeed. But then political issues will begin to interfere. My wife will scream bloody murder if I bring another recumbent into our relationship. She is already more than accommodating with my current mistress, allowing me to store her in the house -- what other wife would allow you to have your mistress under the same roof?! I'm fairly sure another mistress would be out of the question so I'm not even going to ask.
Many Thanks For All Your Advice!
Here's how I see it.
1 you won't be running a big chrystalite on a small battery unless it's sla, or very expensive lithium that has a high discharge rate. Or the less expensive lifepo4 but a very big pack like 30 ah. The less expensive lifepo4 batteries need discharge rates that average less than 30 amps, and the big motor will exeed that enough to give problems later. So figure your battery budget alone is $1500 or more. Unless you go for much much shorter rides, then nimh or nicads could work for that motor.
2 One good solution to problem one is less motor. Do you really need 30 mph plus? If so buy the motorcycle and look at making an electric mototcycle out of it later. If not, a crystalite 408 will be a good choice, and run at 48v on a less expensive 20ah lifepo4 pack will still go in the neighborhood of 25 mph, and believe me, that is pretty fast when you keep that speed constant for an hour or more. Much faster than that should be done on a motorcycle or scooter built for it. I know you have gone much faster on your bike, but belive me, my ebike did 2000 miles of commuting this year and at 25 mph it still take a heck of a pounding day in and day out. It really does beat the stuffing out of a bike to go that fast all the time.
3 Another thing you need to look at, given the riding sytle you describe, is a gearmotor. Ebikesca has one that is fairly light and reliable. The thing about them is they are lighter than direct drive motors and have internal freewheels so they can coast better than direct drive hubmotors that have considerable resistance. The fastest gearmotors avaliable are made by BMC. With a gearmotor all you have to do to ride fairly normally is remove the battery, or you can leave the battery on, and use the motor only as needed. With direct drive motors the drag and the weight is so bad that you have to have power to stand riding it. The gearmotors are also very efficient, so you can get away with smaller battery size and save money there.
4 If you start putting a chinese made direct drive motor on and off the bike frequently, I garantee you will strip out the axle threads since they are so poorly machined. It happens easy enough on one install. Undertightening the nuts is even worse, leading to spun axles cutting the motor wires. If you are lucky, that only costs you a motor and shorted out controller, and you don't go over the handlbars.
My suggestion to you is to look real good at the eezee kit from ebikes.ca . It fits your budget just right, and comes with the backing of the best ebike dealer on the continent. For an idea how good Justin knows ebikes go to the enless sphere fourm and look at the ride across canada thread. If you want the high speed chrystalite, go for it, but use the expertise they have at ebikes.ca to help you make sure you have a battery that can handle the big motor. Those look good, but I think its actually a good thing that my motor goes only 25 mph.
Be the pack leader.
36 volt sla schwinn beach cruiser
36 volt lifepo4 mongoose mtb
24 volt sla + nicad EV Global
Wow! Thank you so much for your analysis and advice!
Of course, I have a few questions.
Regarding your comment #1: You state that this particular motor needs a lithium iron phosphate battery with a "high discharge rate". How can we determine what the discharge rate is? Is this the reason why one web site advertises a Ping 48 volt, 20 amp hour battery for $749 and another web site advertises a 38 volt, 20 amp hour battery for $1,845?
(Web sites: http://www.sdelectricbike.com/LiFePo4_Battery.html – http://www.ecospeed.com/prodbatt.html)
Regarding your comment #2: Twenty-five miles per hour is more than enough for me! I was hoping for twenty miles per hour. I used to be able to average over 14 mph on my commute but now I am barely able to average 10 mph. I thought that going with the bigger motor would help the motor last longer and be more efficient. From what I heard and read, these motors really aren't that well built.
Regarding your comment #3: The eZee bike conversion kit comes with only a 10-amp hour battery. Is 10 amp hours enough for a 20-mile commute? Can the BMC motor run at 48 volts? Would you go with the 400-watt or the 600-watt motor? Or is the difference between a 400-watt and 600-watt the fact that you are using a 36-volt or a 48-volt battery? I guess I really need to look more at the available choices. Is there an information source that compares and contrasts the available motors for us dummies? I'm assuming you are recommending the "eZee Bike Conversion Kit" at http://www.ebikes.ca/store/store_ezee.php.
Regarding your comment #4: I wouldn't be putting the motor on and off. I would have two wheels. One wheel would have the motor on it. The other wheel will not have the motor on it. Just moving the wheel on and off shouldn't hurt the motor, right?
Again, Many Thanks For Any And All Help!