DigitalNerd
1 µW
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I want to build an electric bike. What are the most efficient kits and manufacturers?
Electric Bike Conversion
- Thread starter DigitalNerd
- Start date
ecowheelz
100 W
You're in the right place... just search around the forum...
9C, Amped, Crystalyte, BMC, eZee... just to name a few...
9C, Amped, Crystalyte, BMC, eZee... just to name a few...
dogman dan
1 PW
Efficient to do what specifically?
The MOST efficient ebikes are the slowest. But in my crude tests, a gearmotor going 20 mph is going to use just about the same amount of juice as a direct drive motor riding the same route at the same speed. In the end, efficiency may depend much much more on other factors, such as your own weight, how much you pedal and in what gear, and if the bike is tall or low and slick like a recumbent. Wind resistance from the kind of bike or from speed is the killer.
The reviews and testing section is full of good info on different motors and controllers, and what to expect from them.
The short list breaks into 4 categories.
Through the chain drive stuff, good for lots of hill climbing torque when used in low gears. Rc motors and cyclone kits.
Direct drive motors of moderate size, good for easy installs, decent hill climbing, and ability to go long distances. 9 continent, Aotema, Conhis etc.
Large Direct Drive motors, good for hard use, high speeds overvolted, Usually crystalyte 5300 series motors.
Smaller planetary gearmotors, good for lightweight usually assist type bikes where the motor may not always be used. Bafang, Cute, Amped bikes, etc.
The MOST efficient ebikes are the slowest. But in my crude tests, a gearmotor going 20 mph is going to use just about the same amount of juice as a direct drive motor riding the same route at the same speed. In the end, efficiency may depend much much more on other factors, such as your own weight, how much you pedal and in what gear, and if the bike is tall or low and slick like a recumbent. Wind resistance from the kind of bike or from speed is the killer.
The reviews and testing section is full of good info on different motors and controllers, and what to expect from them.
The short list breaks into 4 categories.
Through the chain drive stuff, good for lots of hill climbing torque when used in low gears. Rc motors and cyclone kits.
Direct drive motors of moderate size, good for easy installs, decent hill climbing, and ability to go long distances. 9 continent, Aotema, Conhis etc.
Large Direct Drive motors, good for hard use, high speeds overvolted, Usually crystalyte 5300 series motors.
Smaller planetary gearmotors, good for lightweight usually assist type bikes where the motor may not always be used. Bafang, Cute, Amped bikes, etc.
LI-ghtcycle
10 MW
Good points DM, and I would also like to add that you want to consider where you ride. Lots of hills or mostly flat can make a difference on what you choose, and if your planning on pedaling with the bike a lot like me, you can considerably increase the range and efficiency of the battery use.
The other thing I would consider is are you looking for a pedal assist, or more of a pedaling optional set-up. If your planning on doing a lot of pedaling, you can make a rather small battery go a good distance even up and down hills a lot. If not, you might want to figure out how many miles you plan to go in a typical trip and build to suit since higher speeds and higher power generally favor RC motor or DD(Direct Drive, no gears to melt) Hub motors.
I started with what I though I wanted to be just a faster than average pedal assist, but I want to go up hills (Lots of them where I live) and I am realizing that keeping the bike under 70 lbs AND having the power I want just isn't possible, and I'm only looking for 20 MPH max going up a 7% grade! Dogman goes much faster with various types of kits in MUCH warmer weather than I will ever see here in Oregon City. :wink:
The other thing I would consider is are you looking for a pedal assist, or more of a pedaling optional set-up. If your planning on doing a lot of pedaling, you can make a rather small battery go a good distance even up and down hills a lot. If not, you might want to figure out how many miles you plan to go in a typical trip and build to suit since higher speeds and higher power generally favor RC motor or DD(Direct Drive, no gears to melt) Hub motors.
I started with what I though I wanted to be just a faster than average pedal assist, but I want to go up hills (Lots of them where I live) and I am realizing that keeping the bike under 70 lbs AND having the power I want just isn't possible, and I'm only looking for 20 MPH max going up a 7% grade! Dogman goes much faster with various types of kits in MUCH warmer weather than I will ever see here in Oregon City. :wink:
dogman dan
1 PW
Actullally I don't go faster than 20 mph up 7% grades. But compared to what I'd be doing pedaling, like 4 mph, going 16-18 mph up 7% is pretty sweet.
I just chose to slow my bike down too, and put a slower wind motor on my commuter. So that bikes max speed is now about 20 mph on 48v battery. It will extend my range, and run cooler up steep hills.
I just chose to slow my bike down too, and put a slower wind motor on my commuter. So that bikes max speed is now about 20 mph on 48v battery. It will extend my range, and run cooler up steep hills.
AussieJester
1 TW
LI-ghtcycle said:
Yes much better DoGMaN
:: wink :: KiM
I researched several kits and settled on e-bikekit. It is simple and very well made. I will attest to 20 miles @ 20 mph. I live in hilly New England and still got that result. I only do pedal assist up steep hills or when I want exercise. I also recommend the lithium ion batteries and quick chargers. They cost more but are worth it. What ever you choose make sure that you get the mounting system for the battery.
http://www.e-bikekit.com/
Enjoy and happy riding.
http://www.e-bikekit.com/
Enjoy and happy riding.
dogman dan
1 PW
I agree. one by one my bikes are all starting to get an Ebikekit motor on em. Nine continent makes a darn good hubmotor.
But till we know where digitalnerd lives, or what kind of riding he'll be doing, it's hard to get too specific about exactly what to recomend.
But till we know where digitalnerd lives, or what kind of riding he'll be doing, it's hard to get too specific about exactly what to recomend.
DigitalNerd
1 µW
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Thanks for the input so far guys. I've been researching the different manufacturers and models thanks to all of your suggestions.
I live in the hills of Ohio but I am planning to make my 30mi round trip commute on a level bike path. What is the advantage if any to having a rear hub motor? What is the advantage of using less voltage? Ex: If you have a 24v 500W vs 48v 500W, what is the advantage of each?
I would like also like to state that I want to incorporate these exact Ultracapacitors into the system if possible. Hopefully with enough of them, I wouldn't need additional batteries. Just not sure how many I would need.
Right now I just need pick out the best hub motor to suit my needs.
I live in the hills of Ohio but I am planning to make my 30mi round trip commute on a level bike path. What is the advantage if any to having a rear hub motor? What is the advantage of using less voltage? Ex: If you have a 24v 500W vs 48v 500W, what is the advantage of each?
I would like also like to state that I want to incorporate these exact Ultracapacitors into the system if possible. Hopefully with enough of them, I wouldn't need additional batteries. Just not sure how many I would need.
Right now I just need pick out the best hub motor to suit my needs.
Ok I was looking through the watt hour thread and one of the better numbers I saw was roughly 10watt hours per a mile.
The biggest cap in your link has 3 wh although because of the steep discharge curve all of it may not be usable with a standard controller. With each of those ultracaps being just over 1lb and $75 from tecate group (hopefully you have a better source like a free source) that 30 mile trip might get heavy and expensive on all ultra caps.
75*3*30 $6750 and 90 lbs of caps wow is that right ew. Maybe just a few to put out a ton of amps and use a milder pack but still looks like an expensive proposal instead of just using a higher c rate pack.
Rear hub motor would mean if somethign happened to the hub motor or mount you won't go face first into pavement. Typically rear dropouts are more robust also. Disadvange is it screws with your gearing if you really use the bike as a bike but with the assist you don't need as many gears so that might not be too much of an issue for most.
All other things being equal the same 500 watt motor wound to go x-speed at 24volts vs the same 500 watt motor wound to go x-speed at 48volts the difference is not that much. You could use a 24 battery instead of 48 but to go the same distance you'd need say a 24volt 20ah battery and a 48volt 10ah battery. 48 volt stuff like chargers, battery management systems, controllers and such cost a little more but not that much more anymore and actually 24 volt stuff can be hard to find, at least I'm finding that way, since the minimum voltage for sale kits is mostly 36 moving to 48. 48 volts to transmit 500 watts would be 10 amps vs 20 amps so there might be less losses in the same size wires or smaller wires and also with the smaller amps they could use lower amp rated electronics. If your limit is say 20 amps then you'd want as high a voltage as possible to sqeeze all the watts you can through so usually that does drive higher volts in performance machines.
The biggest cap in your link has 3 wh although because of the steep discharge curve all of it may not be usable with a standard controller. With each of those ultracaps being just over 1lb and $75 from tecate group (hopefully you have a better source like a free source) that 30 mile trip might get heavy and expensive on all ultra caps.
75*3*30 $6750 and 90 lbs of caps wow is that right ew. Maybe just a few to put out a ton of amps and use a milder pack but still looks like an expensive proposal instead of just using a higher c rate pack.
Rear hub motor would mean if somethign happened to the hub motor or mount you won't go face first into pavement. Typically rear dropouts are more robust also. Disadvange is it screws with your gearing if you really use the bike as a bike but with the assist you don't need as many gears so that might not be too much of an issue for most.
All other things being equal the same 500 watt motor wound to go x-speed at 24volts vs the same 500 watt motor wound to go x-speed at 48volts the difference is not that much. You could use a 24 battery instead of 48 but to go the same distance you'd need say a 24volt 20ah battery and a 48volt 10ah battery. 48 volt stuff like chargers, battery management systems, controllers and such cost a little more but not that much more anymore and actually 24 volt stuff can be hard to find, at least I'm finding that way, since the minimum voltage for sale kits is mostly 36 moving to 48. 48 volts to transmit 500 watts would be 10 amps vs 20 amps so there might be less losses in the same size wires or smaller wires and also with the smaller amps they could use lower amp rated electronics. If your limit is say 20 amps then you'd want as high a voltage as possible to sqeeze all the watts you can through so usually that does drive higher volts in performance machines.
DigitalNerd
1 µW
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Very useful information, thanks evblazer.
The ucaps are definitely free and I have access to at least 30 of them and hopefully even more assuming that they all test ok. Weight seems like the next factor.
Conhis has outstanding prices making it a desirable option just not sure about motor quality and customer service. I'm thinking a cheap build is the way to go for my first project, especially if the power source is free.
The ucaps are definitely free and I have access to at least 30 of them and hopefully even more assuming that they all test ok. Weight seems like the next factor.
Conhis has outstanding prices making it a desirable option just not sure about motor quality and customer service. I'm thinking a cheap build is the way to go for my first project, especially if the power source is free.
If you go pure caps or expect them to have alot of your storage capacity I think the issue in the past was caps give power over a much wider voltage range than a battery would. A 24 volt controller might expect to see and have a usable range of 20 volts to 28 volts due to High and Low Voltage cutoffs. While those could be changed in many controllers many of them won't be able to run certain logic circuits under certain voltages and more importantly if the caps still have usable energy left but are at 6 volts overall the controller will only be able to put 6 volts to the motor and it'll just crawl and be unusable.
If the controller bucks the voltage up it would work but I don't know of any available ebike controller which would be able to do that. A I wonder if layers of series/parralel would work to get at the capacity. Since they are free should be fun to experiment with and come up with something that works.
Not sure if this would help but it talks about limitations of cap only systems and how to work around it.
http://www.fullpowerinc.com/PDF Documents/Backup Power System.pdf
Page 4 shows a graph about the difference in discharge characteristics
"Fig. 4 shows two discharge curves, one with and one without power electronics. In this particular design, 22 cells were used in series for a system voltage of 56 V (2.54 V/ cell). In this installation, the minimum voltage the load could tolerate was 40 V. This meant only 45% of the energy could be delivered to the load if only ultracapacitors were used (discharging from 56 V to 40 V). This is graphically depicted by the solid blue line."
If the controller bucks the voltage up it would work but I don't know of any available ebike controller which would be able to do that. A I wonder if layers of series/parralel would work to get at the capacity. Since they are free should be fun to experiment with and come up with something that works.
Not sure if this would help but it talks about limitations of cap only systems and how to work around it.
http://www.fullpowerinc.com/PDF Documents/Backup Power System.pdf
Page 4 shows a graph about the difference in discharge characteristics
"Fig. 4 shows two discharge curves, one with and one without power electronics. In this particular design, 22 cells were used in series for a system voltage of 56 V (2.54 V/ cell). In this installation, the minimum voltage the load could tolerate was 40 V. This meant only 45% of the energy could be delivered to the load if only ultracapacitors were used (discharging from 56 V to 40 V). This is graphically depicted by the solid blue line."
dogman dan
1 PW
E-Bikekit for the win then for sure. No need to worry about shipping. We never know if you are from the states, or someplace with crazy import duties or shipping fees that make an order from the US expensive. You are too close to thier HQ to consider anybody else. Conhis would be cheap,but your customer service will be located in China, instead of just a few miles away. You can read all about the 9 continent motors in the reviews sections. Lots of raves for that motor compared to conhis.
Front or rear is discussed pretty thourougly in many threads, happy hunting. The basics are, front hub installs on alloy suspension forks are at best for experts, and at worst will destroy your teeth and your forks. But I definitely prefer a front hub on bikes with street tires. Love the better balance between a heavy rear rack and the front wheel, and the way a frontie pulls your through a corner. I get insanely fussy about the install so I can keep my teeth.
In the dirt, everything flip flops, and the motor must be on the rear. So you want rear if the bike will commute to work, but play in the dirt on the weekend. Or you have alloy suspension forks.
For a longer ride like 30 miles, the best bet is a 36v 20 ah battery or a 48v 15 ah battery, and charge at work. (assuming the 30 miles is round trip)
Voltage and amps of controllers gets pretty complicated, but the short answer is more volts turns the motor faster at top speed. So the ebikekit at 36v goes about 23 mph, and at 48v it goes 27mph. 24v is just too slow for most of us these days to bother with. If you like slower, then a slower running winding of the motor is the way to go, and use 48v. Then you still have slowish top speed, but don't bog down on hills. The stock 22 amp controller on the ebikekit is ideal for typical commuters to use, either at 36 or 48v. Big hills would make you want 48v for the extra zip.
Front or rear is discussed pretty thourougly in many threads, happy hunting. The basics are, front hub installs on alloy suspension forks are at best for experts, and at worst will destroy your teeth and your forks. But I definitely prefer a front hub on bikes with street tires. Love the better balance between a heavy rear rack and the front wheel, and the way a frontie pulls your through a corner. I get insanely fussy about the install so I can keep my teeth.
In the dirt, everything flip flops, and the motor must be on the rear. So you want rear if the bike will commute to work, but play in the dirt on the weekend. Or you have alloy suspension forks.
For a longer ride like 30 miles, the best bet is a 36v 20 ah battery or a 48v 15 ah battery, and charge at work. (assuming the 30 miles is round trip)
Voltage and amps of controllers gets pretty complicated, but the short answer is more volts turns the motor faster at top speed. So the ebikekit at 36v goes about 23 mph, and at 48v it goes 27mph. 24v is just too slow for most of us these days to bother with. If you like slower, then a slower running winding of the motor is the way to go, and use 48v. Then you still have slowish top speed, but don't bog down on hills. The stock 22 amp controller on the ebikekit is ideal for typical commuters to use, either at 36 or 48v. Big hills would make you want 48v for the extra zip.
Whiplash
1 MW
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- May 10, 2010
- Messages
- 2,906
Just for what its worth, I can go an EASY 20+ miles with my 10AH Lipo pack with my Conhis Kit. If you are thinking of doing one of these cheaper kits, let me know, I have had good luck with mine. I would venture to say with a 15AH LifePo I would say 40 miles is not out of the question if you take it easy and don't need 30MPH the whole time. It will top out at about 32MPH on a LiFePo 48V pack(53ishV Hot). ( I am running 58V hot off the charger and have radar tested the bike at over 35MPH with no pedaling!) If you have any questions on these kits I have tested mine a lot now and have put over 300 miles on mine, but others have gone WAY over 1000's miles with no problems. There is not too many of the cheaper kits that will do this kind of performance.
