Electric conversions continue to grow in popularity for a variety of reasons. Here is one more that is definitely worth checking out. An “Enduro” is a style of motorcycle that is designed to be a dual-purpose, so it can be run on the street or off-road, however, their features typically make them more at home when they are off-road.
Gabriel in the Philippines
The Philippines is a nation that is made from a group of islands in the west Pacific ocean near the equator. It is north of Australia, South of Japan, and east of Vietnam. It is a lush tropical region, and due to their isolation, the Philippine people have grown to become resilient and resourceful.
The donor for this project is a Chinese steel-framed Rusi KRZ200. As a used off-road motorcycle with a well-worn engine, this particular one was purchased for only $250
The first order of business is to remove the engine and fuel tank to see how much room is available for the electric motor and battery pack…
Golden Motor HPM-10kW
Gabriel already had some experience with the Golden Motor HPM-10kW, and he felt that this was an appropriate motor for this build. The website “Ampsprockets.com” doesn’t make drive sprockets for every motor out there, so the fact that they make 12-tooth sprockets for the GM HPM-10kW is a testament to this motors’ popularity (click here for link).
As you can see from the pic above, the internal configuration of the HPM-10kW uses a single central magnet-disc, and on either side of the rotor is a stator that can be energized to force the rotor to move. This is very similar to the Motenergy motor that was used on the 2011-12 model Zero motorcycles (for that article, click here).
Although the Zero Motorcycle company moved up to a higher-powered motor in 2013, this layout remains a respected motor in its’ size-class due to its power-density and efficiency. 10-kW is 10,000 watts, and at 746 watts per horsepower, this equals 13.4 HP. That may not sound like an impressive number, but electric vehicles are measured on another scale. Gasoline motors need very high RPM’s to get their peak HP numbers, but electric motors have their full torque available at one RPM…plus, electric motors can usually take their continuous power rating and double it as a temporary peak power level during acceleration. It is a phenomenon that has to be experienced to truly understand it.
One area where electric vehicles shine is the way that their torque can be dramatically increased by raising the amps as high as possible during the temporary peak phase of acceleration. Gabriel determined that he could fit 700 of the 18650-format cells on his motorcycle, and with his target voltage of 20S / 72V (nominal), that allowed a paralleled cell count of 35P. Gabriel chose the well-known Samsung 25R cell, which has a factory-rating of 20A. With 35 cells in parallel, this means Gabriel can depend on being able to get [20A X 35P =] 700A peaks from this pack with no danger of it overheating.
This motor may only be able to handle this much power for a short while, but 72V X 700A would be 50,000W / 50-kW, equal to 67-HP.
The “25” in the name 25R refers to it’s capacity of 2500-mAh per cell. With 35 cells in parallel, this means this conversion has [2500mAh X 35P =] 87.5-Ah of range.
There are several companies that are well-regarded for producing battery packs, but they might only have a given set configuration of packs available on their web-site, or…they might not be willing to ship a fully-assembled pack to certain countries. If you need a custom shape or size of battery pack, you may need to build it yourself. Here is an article that I wrote about building packs if you are in that situation (click here).
Gabriel likes hard acceleration, so he programmed the ASI-BAC8000 controller for 450A battery current, and 800A motor phase current. Gabriel purchased the ASI controller from ES member “evolutiongts”, from “Electric Race Technologies” / ERT (click here).
This combination provides 120-km/h (74-MPH)
A Few Extra Bits
Racing the Enduro
Written by Ron/spinningmagnets, May 2019