Dahon electric folding bike

[efold]

This is my first electric bike. I wanted a portable bike that would fit in the trunk of a car as well as in trains, so it had to be a folding bike. After looking for good deals, I finally went for a Dahon Cru D7 (http://www.onbikex.de/Fahrrad/Faltrad-Dahon-Cru_D7_20-29789.html) because of its Chromoly frame and reasonable price. Now for the electrification I bought Cell_mans Mac 8T kit with an A123 battery. I owe my gratitude to Racer_X for inspiring me and answering my many questions. The specs of the kit are:

Mac 500W 8T in a 20" rear wheel
9 fet 3077 controller
16S 4P A123 pack with 48V 5A charger

I'm very satisfied with the service from Paul, highly recommended! To fit the battery on the bike rack, but being able to remove it from the bike when necessary, I bought a bag for the battery and controller (http://www.roseversand.de/artikel/xtreme-gepaecktraegertasche-easybag-mo-2/aid:142460). What I thought to be the inner dimensions of the bag were actually the outer dimensions, hence it is a super tight fit.







Maximum speed is approximately 42 km/h with 100% setting, and 46 km/h with 120% setting (GPS measured). I think this is really the limit for a small wheeled bike on relatively bumpy roads. Acceleration and hill climbing ability is just great. Almost too good, as it attracts peoples attention. I still haven't done enough biking to comment on the battery range, but I will update as soon as I have.

 

[Racer_X]

Congratulations efold on your first build. It turned out very nice, clean and stealthy.
42km/h is the sweet spot here in Scandinavia, any faster and you start to attract unwanted attention from the MAN, Yet still fast enough to smoke 99% of the cyclist during rush hour.
How did it go with the installation of the Mac 8t on the Dahon Cru D7 rear dropouts? Did you have to spread them at all?

If you can it would be nice if you can add some video. Keep us updated, looking forward to any new upgrades or changes to your build.

 

[efold]

Thanks! The rear dropouts on the Dahons have an inner spacing of 133 mm, and the Mac requires 135 mm. So I had to bend the dropouts a bit to fit the Mac, but this was really no problem. I also rasped the dropouts to maka a better fit for the Mac motor with larger diameter than a regular bike wheel.

Today after work I ran out the battery to test its range. Under really aggressive driving (full throttle at 100%/120%, many stops), the battery lasted for 25 km. It will be interesting also to test the battery under more conservative driving.

I will also upload a video once I get a chance to shoot one.

 

[veloman]

Yeah, I'm sure the acceleration is a bowl of cherries with that mac in a small wheel. Nice job and have fun with it!