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Trying to build a high powered ebike

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Trying to build a high powered ebike

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Old 07-24-17, 12:41 AM
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spectastic
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Trying to build a high powered ebike

I've thought about building a electric motorcycle, thinking it'd be a nice project. However, they consume about 116 Wh/mile, while a ebike can get 20 Wh/mile.

So I want to build an ebike that can go fast (maybe 2000-4000W) which should get me to 35-50 mph without pedaling. I also want to put in there a 2.5+ kWh to get me a 100+ mile range.

does anyone have expertise in this realm? what would be the best option to get there in terms of quality, reliability, cost? I'm on a grad student budget, so i don't want to shell out $6k on one of those stock bikes. If I can rig up something for maybe $3000, I'll be happy.
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Old 07-24-17, 09:11 AM
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Go to endlesssphere since most of the information on this forum relates to street (and sometimes trail) legal bikes, not mopeds or motorcycles (depending where you are). What you want is feasible, but your battery pack will be LiPO (never good for a beginner unless you have RC experience).
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Old 07-24-17, 03:21 PM
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Originally Posted by 2old View Post
Go to endlesssphere since most of the information on this forum relates to street (and sometimes trail) legal bikes, not mopeds or motorcycles (depending where you are). What you want is feasible, but your battery pack will be LiPO (never good for a beginner unless you have RC experience).
is lithium polymer more resilient to high amps? why is it not good for beginner?

the setup I'm referring to will have the battery capacity large enough such that full charge/discharge cycles would be ~1.5 hours at the minimum, even at high amp rates. So in that sense, I feel like lithium polymer won't be necessary, because aren't those only used for high c-rate applications (eg. RC planes that only fly for like 30 minutes) or something like that?

thanks for the tip btw. looks like there's a lot of activity on that forum. I think I should be able to get some good info out of those guys.

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Old 07-24-17, 04:44 PM
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LiPO, as you'll discover, is the least expensive, most energy-dense Li battery, but also the most dangerous IMO. The ES crowd gets very excited about high power builds and will assist you. If you need jsut 40 mph an inexpensive direct drive hub motor at 72V should get you there, but use about 50 w-h per mile.
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Old 07-25-17, 06:36 PM
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I am running a 52v with a 48v 1kw motor and easily get speeds in the 45-50mph. But I have never tried to use it as an electric motor bike. Range with pedal assist is around 70 miles of hard use.
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Old 07-29-17, 12:52 PM
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To get your bike to go 45 mph and have a 100 mile range. You would need a 72v 120 ah battery with a 45 amp controller. And a 3500 watt motor

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Old 07-31-17, 07:00 AM
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Yeah, at 120ah, you don't need LiPo. You dont' need an ultra high C rate with that capacity. and there are lots of newer 18650 cells with similar energy density.

At anything over 30mph, your pedaling is a minute power input compared to the battery - at those speeds anything is an electric bicycle.

And yes, the Endlesss Sphere crowd loves high powered builds. ;-)
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Old 08-01-17, 08:42 PM
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To build a 50MPH electric bike using parts available online so you can start to reduce your carbon footprint.
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Old 08-29-17, 08:04 AM
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want to see
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Old 09-04-17, 03:38 AM
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Luna cycle has everything you need. With their 52V battery, Cyclone 3000 mid drive and a 50 amp controller, you're good to 2600W. 60V battery gives you 3000W, which is 4hp.

Your limit for acceleration won't be power but keeping the front wheel down.
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Old 09-12-17, 04:49 PM
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The upper limits of safety on a bicycle frame---very heavily loaded with motors and batteries---in my opinion is in the 25-30 mph range.

Your brakes, suspension, tires, and frame itself are not really designed for the abuse of high speeds.

Also when you get to over 25 mph you are no longer safe to be riding bike trails for the other users.

With an Electric Motorcycle you will have a much more durable frame, heavier brakes tires wheels etc.

There is a guy that lives near me that is doing 30-35 on a cruiser bike with a gas motor---practically no brakes, no suspension. He is just asking for a dog or cat or kid or car to end up in front of him----ugly result.

The super lightweight advantage to low power useage on a bicycle with assist goes away when speeds break about 25mph.
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Old 09-12-17, 04:51 PM
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Originally Posted by CigTech2 View Post
To get your bike to go 45 mph and have a 100 mile range. You would need a 72v 120 ah battery with a 45 amp controller. And a 3500 watt motor
I am not an expert but I think your numbers are off on the low side. I think you need a lot more battery.

Not sure how you figured that out.
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Old 09-12-17, 07:38 PM
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Originally Posted by spectastic View Post
I've thought about building a electric motorcycle, thinking it'd be a nice project. However, they consume about 116 Wh/mile, while a ebike can get 20 Wh/mile.
Ebikes generally use less energy per mile since they go slower. If you build one that goes as fast as an electric motorcycle it may still use a little less energy due to lighter weight, but the air resistance at high speed will require much more energy per mile than bikes operated at lower speeds. And there are safety considerations in using an ebike design at higher speeds.
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Old 09-29-17, 01:09 PM
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Sounds like a cool project although as others have said possibly unsafe. I'd be curious how you wind up going about things.

Do you have any kind of source on that 25 mph limit to bike's lightweight advantage?
And for the frame, I feel like a steel bicycle frame could withstand considerably more than it usually takes, although brakes and suspension would be a big risk.
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Old 10-04-17, 01:46 PM
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+1 Good points Rick.

Originally Posted by Rick Imby View Post
The upper limits of safety on a bicycle frame---very heavily loaded with motors and batteries---in my opinion is in the 25-30 mph range.

Your brakes, suspension, tires, and frame itself are not really designed for the abuse of high speeds.

Also when you get to over 25 mph you are no longer safe to be riding bike trails for the other users.

With an Electric Motorcycle you will have a much more durable frame, heavier brakes tires wheels etc.

There is a guy that lives near me that is doing 30-35 on a cruiser bike with a gas motor---practically no brakes, no suspension. He is just asking for a dog or cat or kid or car to end up in front of him----ugly result.

The super lightweight advantage to low power useage on a bicycle with assist goes away when speeds break about 25mph.
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Old 10-09-17, 09:40 AM
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Another thing to consider when building an electric bike capable of those speeds is licensing and where you can ride. Check you local and state laws. Where I live, if you build an electric motorcycle that does faster than 25 miles an hour without pedaling, you must have a motorcycle license and you canít ride on hiking and bike paths.
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Old 10-18-17, 10:41 PM
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Check out ebikes.ca. Pretty impressive site for electric motors
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Old 06-08-18, 04:24 AM
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Fast ebike build

Originally Posted by spectastic View Post
I've thought about building a electric motorcycle, thinking it'd be a nice project. However, they consume about 116 Wh/mile, while a ebike can get 20 Wh/mile.

So I want to build an ebike that can go fast (maybe 2000-4000W) which should get me to 35-50 mph without pedaling. I also want to put in there a 2.5+ kWh to get me a 100+ mile range.

does anyone have expertise in this realm? what would be the best option to get there in terms of quality, reliability, cost? I'm on a grad student budget, so i don't want to shell out $6k on one of those stock bikes. If I can rig up something for maybe $3000, I'll be happy.
Get you a full suspension down hill bike to start with and make sure you get one with disc brakes and that's a good start.
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Old 06-08-18, 01:46 PM
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Spectastic, did you ever build a bike?
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Old 06-10-18, 11:34 PM
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Fast ebike build

Originally Posted by spectastic View Post
I've thought about building a electric motorcycle, thinking it'd be a nice project. However, they consume about 116 Wh/mile, while a ebike can get 20 Wh/mile.

So I want to build an ebike that can go fast (maybe 2000-4000W) which should get me to 35-50 mph without pedaling. I also want to put in there a 2.5+ kWh to get me a 100+ mile range.

does anyone have expertise in this realm? what would be the best option to get there in terms of quality, reliability, cost? I'm on a grad student budget, so i don't want to shell out $6k on one of those stock bikes. If I can rig up something for maybe $3000, I'll be happy.
60v li ion battery will work for what I think you have in mind. Luna can hook you up.
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Old 06-10-18, 11:47 PM
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Originally Posted by CigTech2 View Post
To get your bike to go 45 mph and have a 100 mile range. You would need a 72v 120 ah battery with a 45 amp controller. And a 3500 watt motor
120ah would probably get you to the next state ,I don't know where you live but that's massive battery power especially at 72v . You don't need all that, 60v and 40 or 50 amps would do it. 60v 24ah Panasonic ga would get you 25 to 30 miles throttle only from my experience and 40 mph is plenty on a bicycle. Enough for road rash 😎
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Old 06-11-18, 03:14 AM
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Originally Posted by Roosterp View Post
120ah would probably get you to the next state ,I don't know where you live but that's massive battery power especially at 72v . You don't need all that, 60v and 40 or 50 amps would do it. 60v 24ah Panasonic ga would get you 25 to 30 miles throttle only from my experience and 40 mph is plenty on a bicycle. Enough for road rash 😎
Here is the deal on why you need so much battery. 1the faster you go the more air drag cuts into you battery. 2 the more battery you need the more the bike weights. So more battery is need for the extra weight. So yes a 60v 24ahr battery will get you 25 mile range. But you have to more then double the amps for the extra weight. Now i said 45 mph. So more volts to get there which adds weight. So more battery still. And i was talking about 100 miles not 50. So there you have it
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Old 06-11-18, 06:16 AM
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Originally Posted by CigTech2 View Post
Here is the deal on why you need so much battery. 1the faster you go the more air drag cuts into you battery. 2 the more battery you need the more the bike weights. So more battery is need for the extra weight. So yes a 60v 24ahr battery will get you 25 mile range. But you have to more then double the amps for the extra weight. Now i said 45 mph. So more volts to get there which adds weight. So more battery still. And i was talking about 100 miles not 50. So there you have it
yeah I won't argue with that but I was trying to keep it in his price range , I don't think he's going to build something like that for $3000 and keep it safe. Just my opinion .
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Old 06-11-18, 06:29 AM
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Originally Posted by Roosterp View Post
yeah I won't argue with that but I was trying to keep it in his price range , I don't think he's going to build something like that for $3000 and keep it safe. Just my opinion .
A 72v 120ah battery would take him to his budget unless he builds Lipo and they're by no means safe and old technology . Li ion is the way to go if you want to do it right. For what he wants to spend he would be better off buying the sur Ron for $3500 at Luna and there you have it 😎
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Old 06-11-18, 08:40 PM
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What batteries would you use?
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