Possible Electric Bicycle ? [ trolling motor ]

[SimpleSimon]

who said 24v ?

ZnsaneRyder

 

[ZnsaneRyder]

At 24V this baby would run at around 2800 rpm,seems a tad ambitious,the centrifugal force on the armature is proportional to rpm squared !.For the same current you would get about twice the power and about the same torque.If you had to get up hills it would be nice to have a variable transmisson,say 2 speeds,preferably more with a 1 to 2 range,otherwise you stand a excellent chance of blowing up the controller,Use a main fuse or breaker to protect it in any case.

High RPM's don't hurt electric motors, and under 3000 RPM isn't very fast. It's the heat from bogging a motor down while giving it high power that kills them and burns the armature coils.

Also, it would be logical to use a controller rated for 100A or more with a 28A motor (56A with 24V). I plan on making my own PWM controller with NTY100N10 MOSFETS, rated for 123A each. And paralleling four of those to have over 480A of current handling. http://www.onsemi.com/pub_link/Collateral/NTY100N10-D.PDF I already built an SMPS with two of those MOSFETS for a different project, and you CAN'T kill them, they are super rugged. Heck with factory controllers, LOL!

 

[duivendyk]

It's all a matter of design,if it can cope with the speed increase,fine.The same goes for the controller with respect to current.Excessive current for too long a time will fry the motor and extreme overload can cause magnetic saturation resulting in catastrophic current increase.The torque required from the motor (say climbing a long hill) determines the current drawn,regardless of voltage and the voltage determines the motor speed,with the motor dissipation being both current& temperature related.Under those conditions having a multispeed transmission can make sense,by keeping the current down,the motor speed&voltage up,thus reducing motor losses and temperature rise

 

[ZnsaneRyder]

I completely agree with you on that one. Would not want to burn out a $100 motor when climbing a hill! Having low gears for the most torque and less speed would be safest for the motor.

I'm just not sure if I can afford a multispeed trans for it. I figure, that if there is too steep of a hill, that's what the pedals are for. Now if one of these was hooked to a shift-kit and used the bicycle gearing, that would be great!

I feel a hybrid gas/electric/pedal combo would be the ultimate setup. We'll see what the future may bring.

 

[arceeguy]

Take a gander at this page! Lots of electric motors, and they have a 24V 450Watt motor with gear reduction and chain sprocket output specifically for bikes at only $99. Electric bikes aren't my thing, but that site has everything from controllers to complete bike kits.

 

[srdavo]

Take a gander at this page! Lots of electric motors, and they have a 24V 450Watt motor with gear reduction and chain sprocket output specifically for bikes at only $99. Electric bikes aren't my thing, but that site has everything from controllers to complete bike kits.

very cool.... thanks for the link!!

 

[duivendyk]

Check out posts by AussiJester,from Perth Australia, he has been busy building a 1000 W trike.Pretty impressive,he made use I think of the multispeed drive train to power it.Interesting video too.

 

[Quadranut]

hmmmmmmmmmm I do remember a 36 lb thrust trolling motor in my garage somewhere........ just might hafta blow the dust of it......... oh wait I was in the middle of a 25 CC weedwhacker build wasn't I ? ??????????

 

[Chris Crew]

Just a guess

I'm new to MB's, but I've messed with boats a bunch.

RPM's are important in a trolling motor because speed=thrust when you are using a skinny little screw (that what we call propellers when they are hooked to the underside of a boat) to push a fluid with very low viscosity (water.)

Trolling motors (at least the ones I have burned up) spin really fast, but they don't have a lot of torque. Granted, on my small boats I've used 35# thrusters--smaller than a 40, but I know logs and stuff in the water will stop the blades from spinning, usually without even breaking the blades off.

I guess considering momentum, once you got rolling, a low torque motor would keep you going, but I think acceleration would be an issue.

Could be wrong, I'm just sayin'.

Now certain cordless tools--circular saws, for instance, and belt sanders (if they make them cordless) would probably have a pretty high torque motor.

 

[sparky]

Well... the small angle grinder was my idea for a super zippy electric motor for an e-bike. Just replace the grinding discs with a sprocket, mount the grinder, add a chain, hook it up to a battery, throw in a switch and potentiometer.... and BAM... that's a dirt cheap e-bike.

I bought my angle grinder for $20 at Hudson's, then I found another Companion brand grinder at Sears for $20.