Shenzen, Baby BaFang & Big BaFang BPM review

[SoSauty]

Lots of curiosity as to BPM out there, read on!

1st, little BaFang. My bike is a dept. store Schwinn ladies Mtn bike bought orginally to get my wife interested yet evolved into my main transportation; e-bike weight 61lbs. I'm a thick legged 185lbs, have owned/ridden 4 e-bikes over the last 2.5 yrs. I bought the Bafang BF-SWXH & Shenzen 36V 20amp controller for a semi-disabled son in law who didn't want it About then a hard crash destroyed my old C-lyte 409, so. . .

Installation Snag1: The 232mm spokes I had should of been 222mm (2nd e-mail seeking advice from jrh not answered), yet I laid awake New Years' Eve and conjored up plans to lace a 4 cross pattern(26" rim). Got it to work and it holds up great, but, don't go this route. I had to devise several 4am sub-strategies to get the last 9 spokes in and it only worked because the length was freakeshly precise. 1mm shorter or longer and it would of been for naught. A straight forward 3 cross is sensible.

Installation Snag2: Another thread helped with the wiring; ie; Blue to Blue and switch the other two. No motor response whatsoever My plea was answered here, there's some great folks with helpful advice on Endless-sphere. Attached the extra little red wire for a key swithch to the main red power wire; Bafang hmmmed beautifully

Installation Suggestion: The motor wires exit on the right. Since I have courier (bike bags) I've never noticed the wires and don't worry about 'em scraping anything. However, the plastic cap for where the wires exit the axel, pretty much forces a 90 degree bend. If I had included a 2nd axle nut, it would of held the cap out another 7/16" and allowed the motor wires to curve more with a less sharp bend.

The name Shenzen Sucteam; what a name,

[SoSauty]

'Shenzen Sucteam' makes me think cheap and true, seems it was $69. But it's a smoothie I use the 36V 20amp controller with a 48V 10ahr Ping batt. Can only feel a little warmth after hard use, no noise, no problems to report. Wish the wires from it were an inch longer but no problem. The big power doesn't come in until around 3/4 throttle, but there's a progressive torque curve from 2mph up to 20+?mph. It's smallesh, 5 1/8", 3 1/4", by 1 7/8", weighs just under 1lb and fits inside the battery bag pocket that I use. At a preliminary 250 miles, the controller has performed flawlessly and the name Shenzen Sucteam now rolls off my tongue in sort of a fond manner.

Bafang8fun: This is a tidbit of a motor. Only 6.6lbs and looks like an internal gear hub, talk about stealthy For 24" and larger wheels, a cross 3 pattern should be no sweat. The finish is a flat grey, with no noticeable imperfections, warped casing, or otherwise as with my older C-lyte; pleasant yet unassuming. The spoke holes in the motor flange may hold 13 or 12 guage spokes, yet are sized so that quality 14 guage spoke heads won't pull through. In addition, the holes were plastic coated (what's the term for this?) which I suppose helps hold spokes with undersized heads. Don't know if this is a plus, but recently Pres Obama was given a similiar Bafang powered e-bike from China.

Feelings: At single digit speeds, it has moderately torquey acceleration. With the nylon plastic gears, there's a soft whrrr noise that fades off as you approach cruise speed. Except for starts and steeper 5%+ hills, it's next to silent, inaudible even when I'm wearing hearing aids. Also the power on/off is seamless. I can't tell when or if a gear engages. Yep, it hits 35mph coasting downhill with the throttle off. It freewheels as a non-motorized bike.

Performance: At least 20W per mile . .

[SoSauty]

I haven't had the chance to ride to LVC (low voltage cutoff) yet. My old C-lyte would run 22-25mi with lite pedalling and required a 4hr batt charge. I've run the Bafang a few times around 20mi and it only requires 3hr charging. It gets at least 20W per mile efficiency, but I hope it'll run 25+ miles per charge with greater efficiency. Pedalling seems to help take the load off 1, or 2, or 3mph above the motor speed. If you pedal more than 3mph above the motor, you are providing all the torque. So, with my set up, lite assist pedalling does compliment 20-23mph+ cruising, yet above that there's not enough motor assist. (300 mile update: assist pedalled 26.5 mi., batt required 3hr15min charge, now estimate 17W per mile and 30 mile longevity )

After 10min of full throttle, no pedal top speed is roughly;
21.5mph

With moderate pedalling;
23.5mph (my gearing also runs out)
Average cruise lite pedalling;
21.5mph
Hill climbing lite pedalling 5%
15mph

In the future I might install a torlon (tougher plastic) or a metal gear as conventional wisdom says that's the BaFang weakness and try the infineon 25amp controller.

[SoSauty]

Next, its' big brother, BPM (BaFang Permanent Magnet). Ordered from ecity website, $154 that included 7 day shipping from China. Nice looking motor, polished casing with no defects. Motor numbers make sense "BPM48V350W26(14)" ; BaFang Permanent Magnet 48volts 350watts wheel 26" (code?windings 14). I'm suspious that this motor is also know as the "Climber."

Both motors, same 48V Ping batt. Used stock schwinn rims and had the stock spokes cut and roll threaded to 216mm which turned out to be a tad long. Got the 2 cross lacing to work by switching to shorter nipples and grinding the protruding spoke points. Think 213mm for used single wall rim would've been closer. Its' size is about 30% greater than little BaFang and weighs in at 8.75lbs. It's a sensorless motor so don't forget to order the senorless controller. Shenzen & BPM motors are soulmates, the connectors from motor/throttle to controller all match. JRH sells both the sensored and senorless Shenzen controllers, and buying from him is easy/reliable http://holmeshobbies.com/home.php?cat=20. I fitted a 5speed freewheel yet looked like room for a 6, possibly a squeezed 7speed. 3 simple 16ga wires exit through the axle on the right. Locking spacers came with it, which I believe help a little, but won't replace a torque arm at higher amps. Positively impressive

Negative, the axle nuts fit loose, even when screwed well up on the axle, there's a felt wiggle. So, there's a fine line between getting the nuts tight enough to withstand the motors' load and stripping the threads

I need my e-bike as reliable as my car for transportation, so choose a 20amp controller, but it may hold up and really fly using 25 or 30amps. Can't tell the difference 'tween a sensored or sensorless controller though I do push ahead a few inches before hitting the throttle. It's quiet like its little bro, a reassuring deep whrrr on start up that becomes subdued at cruise speed. Gear engagement and throughout the speed range is very smoooooth. . Top speed is the same for both motors, yet the BPM is much torqueier, one must be seated when you jam the throttle, nor will you get blown below 20mph in a 10-15mph headwind. I headed up our only local hill, 5% grade for .4 mile, meaning to pedal easy, but couldn't stand looking at 19mph on the speedodmeter, so I pedalled a little more moderate and kept it above 19mph all the way to the top! Under same conditions the little BaFang would hold 16mph. Considering only a 20amp controller with 21.5mph being an average cruise speed, not bad

Could barely feel any motor warmth after 3 mile ride in 10-15mph headwind. Controller got hot enough that I could just keep my fingers on it. (update edit) There was some decorative netting on the pocket. So I cut the inside pocket insulation out from around the contoller. Air flows into the pocket now and Shenzen only gets faintly warm.

OK, I saved the best for last:

Top speed motor only:
: 21.5mph

with moderate pedalling:
top speed;
23.5mph
cruising speed lite pedalling
21.5mph
5% hill climb lite pedalling;
18mph

Still pretty stealthy looking; compare to little BaFang in photo above

BPMSchwinn.jpg (48.64 KiB) Viewed 1204 times

Left 'Cute Motor' Right "BPM Motor"

[TPA]

When did you order the BPM motor? Their website is down, and I no longer see it listed on eBay.

Just curious how to get one now. I sent them a message through eBay to see if they can still get them...we will see.

[SoSauty]

TPA, just go on the ecity web site, scroll down to the bottom of the page, e-mail 'em what you are interested in and request a shipping quote. I paid via Paypal. Ordered 4/9, on my doorstep 4/16. Think 'Alibaba' is an international type e-bay seller.

http://ecity.en.alibaba.com/product/257487493-200057916/BPM_Permanent_Magnet_Brushless_High_Speed_Motor.html