Unique mid drive gearbox, rc motor?

garp

garp

10 mW
Joined
Aug 30, 2010
Messages
32
Location
Eden, New South Wales, Australia
I would appreciate it if some kind person would help me to select a motor and controller for a mid drive project I've been working on for a while.
I've been searching for a long time but I haven't got any practical experience with electric motors so it's hard to know if I'm on the right track.
The transmission incorporates the pedal shaft and the front sprocket is driven. I have 100/1 reduction between the drive and the sprocket so I'm after a motor that pulls about 6 to 8 thousand revs. I'm running a Shimano 7 speed hub but I may fit a 4 speed automatic hub that I haven't used yet. It's been running a Honda gx31 brush-cutter motor but I'm keen to electrify it
I've been looking at brushless rc crawler motors, programmable torque curves, sensored etc. Would one of these motors be strong enough? I would need at least 500/1000w. I want to keep it light though, I don't want to have to stack it up with batteries. 5/6 miles would cover my needs for this bike.
I'm going to use DeWalt batteries. kfongs post is excellent news.
I'd also like to use a smartphone as a key/display/program selector. Has anyone done this?
I'll post some pics as I go but if you want to see it in it's present form http://www.motoredbikes.com/showthread.php?29195-Unique-gearbox-for-weedeaters.
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You've come to the right forum. Suggestion: you should include the purpose or expectations of your project (how are you going to use and abuse it). Speed, range, terrain, budget, weight, etc.
 
Thank's for that, ok then...
I use this bike in the mountains and on dirt tracks mainly so power restrictions don't worry me. The Honda motor puts out about 1kw which is enough to move it along quite nicely with the gears. It weighs 24kgs ready to go, I'm hoping to keep it light as my range expectations are not huge.
I don't mind spending a bit to get the right stuff, as long as it's fun to use. I've been interested in electric vehicles since I first saw the moon buggy, now it's time to have one.
 
I've just found Speedict, just what I was looking for. I hope the note 3 is waterproof.
All I need now is the right motor and controller, this is where I would value some good advice from you clever people...
I would like to be able to plug in DeWalt 36v, or possibly 28v nano phosphate batteries as I need them, in sockets attached to the frame. Either one, two or three at a time. Is this possible? If so what would be the best motor/esc combo that would produce 1kw or so?
I'm finding motor and esc ratings very confusing at this point,I hope that once I get hands on with this stuff it will start to become clearer to me. Electrics are not my strong point, probably something to do with being colour blind/dumb.
 
I'm thinking maybe DeWalt batteries are not the most appropriate, I thought they might be convenient... I'm not fixed on using them, whatever is best. please advise.
Will an rc motor be robust enough for a bike? Hobby shops I've rung have told me no. I don't think they want to get involved with my hairbrained schemes lol.
I hope to get it finished by March, I just have to be confident I get the right stuff. It's great fun with the Honda motor, using the gears makes it very versatile even though it's a puny engine. The right motor/battery/esc will make this a delight.
attachment.php
 
That's a cool bike. Yeah there are a lot of builds with RC motors that are working very well. My bike will hopefully soon be back to being one of those :lol:
if you search around you'll find a lot of information. For just one kilowatt, you won't need a big motor. I think one of the 63mm motors would work well. You will need a few dewalt batteries in parallel to supply the motor with full power because rc motors trend to draw more ampps than volts.
 
I would go for this motor http://www.leaderhobby.com/product.asp?ID=9394001224161, fit it with hall sensors and run it with a 12fet e-bike controller these motors are good for 4.5kw peak and around 2.5kw cont, you will have to either mod or buy a modded 12fet controller to run at these power levels, but if you only want low power then run it on 24v at around 50A with a stock 12fet controller.

Edit:
If you dont mind peddeling a little to get going you counld even drop the hall sensors and go for a cheap 200A 24v rc esc ( makes things a little easier/cheaper )
 
Smooth take off and accurate low speed control are important to me, is this dictated by the esc or would a sensored motor be required?
At the moment there is a centrifugal clutch as input, I was just thinking this would help support the bearings in the motor if I left it as such, and provide a smooth start. Any thoughts?
 
Keeping the clutch would allow a sensorless controller like gwhy! suggestes...

his is an excellent suggestion, I would go that route too

Smooth control etc is dictated by the ESC. Most if not all of them are speed control, not torque control.
 
Another thing I want is for it to sound good. I've heard a few rattly ones so far, my gearbox is all helical cut and silent. Do the motors rattle or are some people running straight cut gears?
 
I spotted this in the forsale section if i had spare cash i would snap it up myself

http://endless-sphere.com/forums/viewtopic.php?f=9&t=47559

The ESC aint much chop but it has external hall sensor bracket one of yours
by looks is it GWhy? I have used several of these Turnigy 80/100s and they
give you some serious mojo.. here's a video of my Turnigy powered e-bike, give you
some idea of the speed they can generate...

Best of luck.. and welcome to the forum good to have another Aussie aboard :D

KiM
 
I don't mind spending a grand or so, that's about my budget for this project. I probably don't need that much power, but it would be nice. About 1/1.5 kw would be good.
How much battery would I need for 5/6 miles?
 
if your looking for a nice easy build try a cyclone motor they come 24 v 36v and 48v 500w 960w 1200w and now 1600w with kelly controler
 
I've just been talking with H.K. They recommend These items...

http://www.hobbyking.com/hobbyking/store/__21410__ZIPPY_Compact_3300mAh_10S_35C_Lipo_Pack.html

http://www.hobbyking.com/hobbyking/store/__4691__TURNIGY_Sentilon100A_HV_5_12S_BESC_Ver4_.html

http://www.hobbyking.com/hobbyking/store/__6609__iCharger_1010Bplus_300W_10s_Balance_Charger.html

http://www.hobbyking.com/hobbyking/store/__19040__Turnigy_G160_Brushless_Outrunner_290kv_160_Glow_.html

I really want a controlled motor but they said there wasn't one big enough. They also offered me a different charger and batteries plus a throttle that brought the total down to less than $280 + shipping. I expected to pay more than this, I've been saving my goldies for ages. Is this stuff up to the job?

It will be less now because I have to buy batts here.

http://www.hobbyking.com/hobbyking/store/__10608__Hobby_King_GT_2_2_4Ghz_2Ch_Tx_Rx.html
 
garp said:
I've just been talking with H.K. They recommend These items...

http://www.hobbyking.com/hobbyking/store/__21410__ZIPPY_Compact_3300mAh_10S_35C_Lipo_Pack.html

http://www.hobbyking.com/hobbyking/store/__4691__TURNIGY_Sentilon100A_HV_5_12S_BESC_Ver4_.html

http://www.hobbyking.com/hobbyking/store/__6609__iCharger_1010Bplus_300W_10s_Balance_Charger.html

http://www.hobbyking.com/hobbyking/store/__19040__Turnigy_G160_Brushless_Outrunner_290kv_160_Glow_.htmll
Click to expand...

:shock: I suggest you wait for a better recommendation !
I wouldnt touch that motor/ESC combination, and why the 3300 mAhr batts ???
Even the charger is far from ideal.
 
garp,
Please remember that if you use a rc motor that the reduction will have to be quite substantial... unless you run the motor on 24v or less, by keeping the working voltage down to this sort of level it will make the whole experience a little cheaper and a little easier, then you can always up scale after you see how you get on.

2x 5000mah 22.2v lipos
1x 350W lipo charger ( good enough to get you going total charge time for 2x lipos around 4 hours)
1x laptop psu for small lipo charger
1x 170kv 3250w outrunner
1x mystery 200A lv controller
1x servo tester
1x throttle
various wire and connectors
plus all your hardware to put it on the bike

and you are more or less sorted to start playing ,
gear it very low for pulling away and it should be fine.

to scale up: buy more batterys, bigger controller and re-gear ( but it do get a fair bit more expensive and complicated with the higher voltage/speed )

Edit:
I have used a mystery 200A lv controller and although its no thrills it did work rather well..
 
IMHO...
80/100, 130kv motor,
Castle 160 controller
24/35 v HK lipo packs to suit
CA3 for monitoring and throttle interface.
your biggest issue will be the mechanical motor mount and coupling of the motor to existing gearbox.
 
Hillhater said:
IMHO...
80/100, 130kv motor,
Castle 160 controller
24/35 v HK lipo packs to suit
CA3 for monitoring and throttle interface.
your biggest issue will be the mechanical motor mount and coupling of the motor to existing gearbox.
Click to expand...

I think that's a little excessive since he only wants 1kw.
 
Thank's everyone for taking an interest and giving me help. I've been in front of the computer day and night for weeks now looking for the right answer.
I'm not trying to make a light weight electric motorcycle [maybe later...] I want a nice little electric pushbike. It has to run well at 200w to be legal here, if it had more power offroad that would be great, but it has to remain light.
.
 
Ok, the process has begun. The motor is ordered.
I would like to thank gwhy for his guidance, it was indeed an excellent choice I realize now after hours of study...
Also Lebowski who confirmed it, and cleverly pointed out that a clutch would alleviate my concerns regarding ride-ability.
My next worry is speed control. I've read the esc's don't like running on light loads, I'm thinking a lot of my riding will be part throttle. Will it be a problem?
Would this be sufficient? I've read about voltage spikes and various other horrors, would anything need to be modified to ensure reliability?
http://www.worldhobbies.com/product/CC-PHX-I160HV_item.html?ref_cat_id=BPDC
Or should I buy something else?
Like this...
http://kellycontroller.com/keb72450x24v-72v220a45kwe-bike-brushless-controller-p-275.html
 
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