Moped Conversion

[Ryan]

I have a 1980 Motobecane Moby moped with a 50cc 50V gas engine (see picture below).  I want to remove the gas engine and replace it with a Goldenmotor HPM5000B BLDC motor.  I realize this is going to be a project, but let's assume for the moment that all of the logistical/engineering steps were completed to install the motor and battery/batteries, controller, controls, etc. into the moped. Does this motor have the power to move the weight of this bike and rider (i.e. does a 5kW motor have more horsepower than a 50cc engine, assuming proper battery power)?  What GM battery/batteries would be best to power the motor?  Does the BLDC motor controller come with some sort of cable that would be pinned out correctly to support the motor controls (if not, how would such a cable be designed)?  Could multiple batteries be linked in series to allow for longer range?  Your input will be appreciated and will significantly influence a purchase decision.

rbuchmann

[Bikemad]

I would not even consider converting one of those mopeds to electric power, basically because there is nowhere on that moped suitable to mount the large volume of batteries that would be required to get any decent range out of it:



The HPM5000B motor would be able to power it with ease, and with the right battery pack, it should easily produce twice the power of the 50cc gas engine, but it would be quite involved to get the motor suitably mounted to that frame.

Erik had the right idea of simply upgrading an existing electric scooter by fitting a more powerful hubmotor and a decent battery pack.
Check out Erik's post for more details.

If you want my advice, do yourself a big favour and forget any ideas about putting the HPM5000B into that particular moped.

Alan
 

[MonkeyMagic]

That moby moped is awesome!!!! Do they make them for men? lol jokes
I forget the formula but a 50cc engine equates to around 2100W at full power output. So yes - it has at least double, I would say near triple the power output. Yum

There would also be no traction if you did put 5Kw through that wheel! Man that would be awesome fun though

Hehe I like rBuchmann's style



Hey PS: Alan whos scooter is that?

MM

[Bikemad]

Hey PS: Alan whos scooter is that?

That's Erik's scooter as can be seen in Erik's post that I already mentioned.

I thought it would be a good way to show just how much battery space is required to achieve a decent range with a more powerful motor.

Alan

[Ryan]

I looked carefully at Erik's post presenting his scooter conversion experience.  He chose well in terms of selecting a motor for power and a sufficient number and size of batteries to provide him with adequate range.  The main drawback to his design is that the speed of the scooter is directly linked to the speed of the hub motor.  If a car were designed in the same way, it would forced to run in one gear at all times.  This is extraordinarily ineffecient and would require an enormous gas tank to enable the car to go any reasonable distance.  Hence the reason Erik requires this massive battery pack.  To alleviate this problem, automobile manufactures designed the transmission.  Using the transmission, the engine operates at its peak power and efficiency over a greater range while keeping the vehicle in motion.  It also enables the vehicle to take advantage of inertia to keep the vehicle moving instead of entirely relying on the motor or engine for power.  So a car traveling in 5th gear can travel at 60mph at 2500rpm (cruising speed) but has very little power, for example, whereas in 1st gear at 2500rpm, the car is limited to speeds as low as 10-15mph but has great power.  Such a device has been designed for a light electric vehicle.  Behold: the Nuvinci continuous variable planetary transmission (http://www.fallbrooktech.com/09_LEV_Kit.asp)!  Adding to the Nuvinci's benefits is an automatic shift actuator that can be programmed from a PC to electronically shift at the peak performance of the motor.   When the motor needs more power, as when climbing a hill, the Nuvinci will shift accordingly based on tables that are loaded into the shift actuator's firmware.  Here is a link to the datasheet: http://www.fallbrooktech.com/docs/DevKit_Datasheet.pdf and the User's Manual: http://www.fallbrooktech.com/docs/DevKit_Manual.pdf

So consider the diminutive moped: it is engineered to use a motor, so it has the space designed into the frame to accommodate an electric motor like the HPM5000B.  Since everything else is getting tossed, there will be plenty of room for a sizeable battery, and a second one could also be stashed under the seat.  The Nuvinci CVP hub is installed in the center of the rear wheel (note how the rear wheel on the moped is a standard spoked wheel, unlike the wheel on a scooter).  Connect the motor to the Nuvinci hub using a toothed drive belt (cleaner that way) and you now have a very efficient drive train for an electric bike!

Now I realize that there is plenty of custom installation and configuration work that would have to take place in order to make this moped run properly, but the simple truth is this: with a CVP transmission in the drive train, it is now no longer necessary to cart massive battery packs in order to improve the efficiency, power and range of your electric bicycle or moped.  Read the white paper and see for yourself! http://www.fallbrooktech.com/docs/LEV_CVT_WhitepaperRev10.pdf

[MonkeyMagic]

Erik had the right idea of simply upgrading an existing electric scooter by fitting a more powerful hubmotor and a decent battery pack.
Check out Erik's post for more details.

I somehow missed that sentence sorry mate!!
whoopsies