Bafang Kit review

Russell

1 MW
Joined
Nov 22, 2008
Messages
2,014
Location
State of Wisconsin, USA
I was looking for a small geared motor when I ran across this kit on eBay.

http://cgi.ebay.com/250W-36v-Electric-Bike-Conversion-Kit-SAVE-GAS_W0QQitemZ320318877354QQcmdZViewItemQQptZCycling_Parts_Accessories?hash=item320318877354&_trksid=p3911.c0.m14&_trkparms=72%3A1205%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318

I was told by the seller it was manufactured by Suzhou (the guys who manufacture the Bafang). I wanted the kit for my Raleigh hybrid so I took a chance the 28" wheel was 700C since that’s how many people refer to the 700C size outside the USA. The wheel was actually 635mm and not the 622mm I had hoped. The rim was a very wide 32mm single-wall laced to the motor with 13G spokes in a 1X pattern with the spokes not touching at the cross. It was way out of true though that didn’t matter to me any longer. I laced the motor to a Sun 700C CR18 rim using Wheelsmith DH-13 butted spokes size 258mm (260 would have been better) in a 2X pattern. The controller is small (approx. 3" x 2 1/2" x 1 1/4") and is rated at 7A/15A peak. The 3 SLA batteries are 12V/9Ah in their own little tote bag you can remove from the rear rack bag. A 36V 1.8A charger is included. The straps for the rear bag are awkward and don't cinch down very well. I'm going to put a plate in the bottom of it and bolt it down to my rear rack. The controller is stored in the rear rack bag as well though for convenience I have mounted it on the handlebars with a Watt's Up meter on top. The throttle is your run of the mill full twist plastic model with LED’s.

One thing leads to another so I haven’t finished the bike yet. It’s too cold and snowy here in Wisconsin to ride anyway. I know I’ll hate the twist throttle so I will be trying out different throttles and brake/shifter combinations. I did secure the bike’s front wheel in my trainer and ran it at full speed. On a fresh charge it registered a top speed of 17.3mph according to the bike’s speedometer calibrated for the 700x35 tire. The Watt’s Up meter showed the motor was pulling an average of 170W at between 4.5 and 5.0 amps with a peak on acceleration of 14A. The trainer displayed about 126W to start, though I don’t know how accurate that is, for an efficiency of 74%. The speed trailed off as the voltage went down and after 5AH and 16.8 miles was 15.9mph. The battery hit the 31.5V controller cutoff voltage at 5.7AH delivering 199WH after 19.5 miles. I expect the on-road results to be a bit slower without pedaling since I routinely spin faster on my trainer than out on the road.

All in all it’s not a bad beginner kit for someone who wants a small geared motor though for me the shipping from Canada and having to re-lace the wheel added to the cost. It is one of the few Bafang motor kits available on the market though I see Cycle9 has some 8Fun kits with a lithium battery starting at $699 for a 24V system. Still it would probably be better to buy the parts separate especially if you don’t want the SLA battery pack and you don’t mind matching up a compatible controller. As my first kit to play around with it should suit me just fine.
 
I though that looked like a good choice for somebody wanting a lot of range without the cost of a big battery. A watt miser, but being geared, still able to pull a hill I bet.
 
It's a really good motor, and most likely about as fun as it can get. Durability of the nylon gears is poor, and there are only two people who's motors survived long term (I am one). One key is not to go over 48v with nylon. Try to minimise sudden hard accelerations from lights. Keywin has the steel gears, which will allow for 72-80v operation, and that I imagine must be a blast to try.

Later
Nog
 
Does the motor give you enough power with those large wheels?

Looks good, nice and tidy, without the bulk of some monster hubs on the market.
 
Recumbent,

I have not had the opportunity to ride the bike yet given we're deep into winter here. This is a low power/low speed system with a controller limited to 14A. I tested it under load on my indoor trainer and it delivered a maximum speed of 17.3MPH which fell to 15.9MPH after consuming 5AH from the 9AH SLA pack. Based on that I estimate it will deliver ~16.5MPH (max) on the flats in the real world. This should suit me just fine since the average trip speed of my last 31 rides on this particular bike before the conversion was 15.1MPH over my usual 1.5-2 hour rides.

I ride a bike for fitness so I did not want to build a moped and just go along for the ride. I've wanted to try some type of motor assist for quite a while so I wouldn't kill myself on the hills and into headwinds but have been reluctant to do so because of cost and the desire to keep the bike an enjoyable and efficient bike to pedal. Because of this the low weight and the ability of the geared Bafang to freewheel were major reasons for choosing it. I will be switching to some sort of lithium battery in the future to get the weight down since the bike now weighs more than I’d prefer (~62 pounds).

I usually don't get back on the road until sometime in early March so a road test will have to wait for a while. It's always tough to get going again in the spring after months of inactivity (I hate winter) but the motor assist should help there too. I will post a road test when I do finally get a chance to ride. If I like the results I may then use what I've learned to motorize my new Kona Smoke which is the bike I planned to convert in the first place. That'll still leave me my lightweight Cannondale 1x9 for when I just wanna ride unencumbered. :)


-R
 
I just had a chance to test my newly rebuilt (with 1 steel gear) Bafang and it is powerful and quiet! Unfortunately, My chain was mis threaded thru my new deraileur (I wonder who did that?) and I had the worlds fastest three wheeled wheelchair! I gradually built up the throttle to about 15 MPH and still had a bunch of power to use! Since I ride for exercise as well as recreation and short errands, I reluctantly stopped the test and rethreaded the chain! More tomorrow! This is with a 48 volt 20 ah ping! Way too much power maybe! And it is huge! The takeoff compared to my interm brush motor is much better, even with part throttle! And it cant lock up the rear wheel, I hope! :shock:
otherDoc
 
docnjoj said:
I just had a chance to test my newly rebuilt (with 1 steel gear) Bafang and it is powerful and quiet! Unfortunately, My chain was mis threaded thru my new deraileur (I wonder who did that?) and I had the worlds fastest three wheeled wheelchair! I gradually built up the throttle to about 15 MPH and still had a bunch of power to use! Since I ride for exercise as well as recreation and short errands, I reluctantly stopped the test and rethreaded the chain! More tomorrow! This is with a 48 volt 20 ah ping! Way too much power maybe! And it is huge! The takeoff compared to my interm brush motor is much better, even with part throttle! And it cant lock up the rear wheel, I hope! :shock:
otherDoc

It would be nice to have that steel gear for insurance but I don't think I'll have a problem with it (knock wood) at 36V/15A.

I've read where others are getting 22 mph at 48V with their Bafang motors but with your lower stance it's very possible that you'll exceed that a little. I only get about 16.5 mph on level pavement on a fresh charge and all assist is gone by 18 mph. That speed won't excite many but it really is comforting having the help and it also allows me to squeeze over 20 miles out of 5AH. With the pack you have I could probably go 100 miles though with that virtually "unlimited" juice available I'm sure I'd use the throttle much more. I can't go to a 48V pack since my controller has 50V caps but I'm thinking of perhaps adding a booster pack to my SLA's until I pony up for a lithium battery. I probably should just spring for lithium right away but I hate to waste the SLA's. The strange thing is while the extra weight is noticeable on grades it almost seems to make the bike ride smoother out on the road and with the freewheeling Bafang it pedals and coasts just like a regular bike. I really like it. :)

-R
 
Back
Top