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.
Thanks for the update. Every time I hear about a new western manufacture motor I get excited but know I will be disappointed by the price. 1700 Euros! Gawd! You could buy a good used car for that much. There is NOTHING in that motor that should make it cost that much.
Thanks for the tip on the Turnigy. I was familiar with them from my electric powered RC plane but didn't know they went up that high in power.
Just a word of warning if you didn't catch it yourself: It looks like their maximum power figure of 130amps X 48v is the maximum power it draws and not the maximum it puts out. Still, even if it only operates at ~30% efficiency you could still have yourself a winner. What isn't work will be heat so it could end up being the mechanical equivalent of a rotating hot plate.
When you buy R/C you are leveraging the R/C crowd's buying power for that mass produced pricing.. not a bad way to go. The 130kv 6500watt motor is a probably the best pick, and $150. The "monster ESC" isn't a bad deal either, although you might want more volts than it can do. These motors can take double the rated voltage. Don't forget the R/C guys have some excellent batteries also!
What throttle setup are you going to run with that esc??
First let me say that the guys at CPM is very friendly, and called me to ask/explain about their motors. And yes they are expensive, but quality and performance is in top and developing costs, you know.. I just hope that they will get some massproduction going, so the prices comes down. They are btw developing a 20-80kw motor with a weight around 15 kgs...
The 80100-130 motor and monster 2000 ESC is what i ordered I also ordered a servo tester (for throttle) a UBEC and a lipo to run the tester/ main relay.
Also i have ordered another option for the throttle device- a pot box and a throttlizer... I did this as im not sure the servo tester will work/keep on working. The bikes gets pretty beaten up from time to time
I have checked the lipo batts, and getting pretty hot on those And if the life cant deliver, i will go for lipos thats for sure...
Now i just hope i can get everything wired up the right way
Cool, sounds like you're building it the right way! Some of these gas guys love talk smack on electrics.. mostly I think its because hardly anyone steps up the plate to show them what electrics can really do.
I have some yum RC lipo I just got. Going to give it a whirl and see how it does. Coming from lead its shockingly compact for the power..
Well, in 3-4 month when the season starts up here, we will be the ones that do the smackin And the best part is that our raceassosiasion cant deny us to ride in the class, due to the danish enviromental laws So, gas guys, watch out here we come
Guido, what are the specs on your lipo pack ?
Let me know how it goes...
Its just the standard 20c turnigy 5.0 packs. I see they are now priced under $10 per cell.. they also dropped prices on the higher C ones. With shipping still pricey, but not as bad as before.
I have bought 16 cells so far. Got to step up to the plate if you want the good performance though.. I'll probably buy more when I can afford it. I also have a brushless motor and controller I'm thinking about trying on my son's PR200 in my avatar but they might go to another project instead.
They now have 25c cells for less than I paid for my 20c cells. Dont you hate it when that happens, doh!
I have an accucel that does balancing. I have a few other chargers also. Yes like 60v or so hot off the charger. Similar to 4 slas.
Going to wire up a 4-series wire adapter for the four packs using the 4mm paired bullet connectors. That way I wont have to cut anything on the packs. Its 5ah only for now, just for a messing around the street pack. The high Cmax makes this possible! In reality my 12ah sla pack only puts out around 5 or 6ah at high loads because of peukurt losses. Soo it should keep me happy even like this.
For your paralleling packs up on your PW check out the parallel adapters at tppacks *** com. They are inexpensive and will get you up to a 20ah pack! 30$ for each 22.2v of your pack, not bad for saving some headaches. Oh, and gravy, it has a low voltage protection feature too!
BTW I might pickup a way hammered PW for my kids next week from my buddy.. price is right! You should also think about the dangers of lipo if you have a kid riding. I would use an unsealed steel box that vents away from the rider. Its easier than it sounds to find such a box. Like an office cash box or toolbox or lunchbox or something should be good. Lipo is in your cell phone, digicam, and laptop just to give you an idea of how safe it is when used properly, but safer than sorrier and all that. Kids on bikes is an unpredictable thing..
