Hi all, new here.
Short story first... Ive been chalenged to built an electric bike that can compete against ICE bikes, (yamaha pw 50 type)... Its to race on an oval track, 4 laps, like this; YouTube - Grindsted 2008
Topspeed is about 37-38 mph, and track length about 0,5 mile.
My question is; can this be done with an E-bike, and what electric gear is nedded?
Look forward to some response to this
BTW i know absolutely nothing about electric parts
Kris
Hi Guido
thanks for your reply.
I pretty much have what i need to make the bike. My problems are about the electric setup; size of engine, batteries, controller, ect...
Ive been looking at the perm motors, and as you mention, they are a little pricy.
Ive found out that torque is important. Also weight is important for bike handling. I like the complete bike to weigh about 75-80 lbs. Budget i estimate about 800-1000 usd for electric components ex batteries ( i have 16 TS cells 20ah, i hoped i could use)
Please let me hear your, and others, suggestions...
Just an opinion but it could be tough to do even with $1,000 and be competitive. You may want to see if Zero will give you a break on parts in exhange for promotion.
That being said, you can buy a 1200 Watt motor off eBay for ~$100. 746 Watts => 1 hp. Watts is voltsXamps. Largest controller I saw on eBay was 1,000 Watts so I what I would do is run the motor slightly underated i.e. instead of hitting it with 48V just wire the batteries for about 40V and take the hit. Electric horses are bigger then gas horses. The ~1.2 hp you would get from this set up would roughly be equivalent to a stock ~2-3hp PW50.
Prices really go up for electric parts as power goes up. I think Zero was using ~$900 16hp electric motors in their MX bike. The controller and battery pack probably cost more then the motor.
I think perhaps the zero setup is little too much for my bike, but good point though.
Yes ive checked ebay, but will these motors deliver the power that i need? Also i was hoping to go 24v on the system, because of batteryweight.
About hp, thats great info for me...Do you know why there is this difference???
yeah, i see that PMG 132 is close to 1k...
I was hoping to find a motor that weighs about 10lbs. I found this; CPM - Compact Power Motors :: Home
Anyone knows these motors?
They use those motors in electric golf carts...They have tons of torque and get the golf carts going pretty fast.now youll need a place for fitting all those batteries......If I was gonna build an electric i'd consider one of those big time......Peace
I think perhaps the zero setup is little too much for my bike, but good point though.
Yes ive checked ebay, but will these motors deliver the power that i need? Also i was hoping to go 24v on the system, because of batteryweight.
About hp, thats great info for me...Do you know why there is this difference???
yeah, i see that PMG 132 is close to 1k...
I was hoping to find a motor that weighs about 10lbs. I found this; CPM - Compact Power Motors :: Home
Anyone knows these motors?
I certainly hope you get lucky with the CPM motors because I would like to try them too if the price is right. Downside is in my experience new design western motors typically sell at ~$1/Watt. Old technology goes cheaper but is not efficient. i.e. we have a couple of beat up electric golf carts on our ranch and they use electro magnets for the field => batteries have to supply current for both the armature and the field! IOW old tech that you can get cheap is liable to be 1/2 as efficient which puts you in a battery and weight bind.
The reason electric horse power is bigger is because of the torque performance vs. load. They are closer to a steam engine in that they put out the most torque at low RPMs. I think Jay Leno said his single cylinder 1912 Stanley Steamer, the one he a speeding ticket with, puts out 800 ft-lbs of torque at 0 RPM. If you look at a torque vs. RPM curve for an electric you will see it runs down hill compared to a gas engine.
I may misspeak here but for acceleration it is power area under the curve, AUC, over the RPM range that determines the ET to speed. A graph would display it better but points for torque electric vs. gas would be something like
electric,gas
1000 RPM 1.5, .4
2500 RPM 1.4, 1.0
5000 RPM 1.2, 2.5
I certainly hope you get lucky with the CPM motors because I would like to try them too if the price is right. Downside is in my experience new design western motors typically sell at ~$1/Watt. Old technology goes cheaper but is not efficient. i.e. we have a couple of beat up electric golf carts on our ranch and they use electro magnets for the field => batteries have to supply current for both the armature and the field! IOW old tech that you can get cheap is liable to be 1/2 as efficient which puts you in a battery and weight bind.
The reason electric horse power is bigger is because of the torque performance vs. load. They are closer to a steam engine in that they put out the most torque at low RPMs. I think Jay Leno said his single cylinder 1912 Stanley Steamer, the one he a speeding ticket with, puts out 800 ft-lbs of torque at 0 RPM. If you look at a torque vs. RPM curve for an electric you will see it runs down hill compared to a gas engine.
I may misspeak here but for acceleration it is power area under the curve, AUC, over the RPM range that determines the ET to speed. A graph would display it better but points for torque electric vs. gas would be something like
electric,gas
1000 RPM 1.5, .4
2500 RPM 1.4, 1.0
5000 RPM 1.2, 2.5
Rick
I have made a request to cpm... If they reply, i let you know
I understand about the hp/torque thing...But when im building anyway, i might as well built it so im sure it will beat the PW`s
When we roll the PW in a testbench ( or what ever you call it ;o)), the power is around 2.9hp. And the torque is 3.8 nm. We do 4 laps in a heat, and we do 5-6 heats in a race...So yes, by reading inhere and others, it should be possible to get the speed and power needed.
