New Bafang Crank-Drives

Kepler said:
Just checked out your blog. Wow, great job so far. Look forward to seeing the finish product. It should make a great reference site. 8)

Thanks. The dumb newbies approach to an ebike conversion ... counters all the technical and skilled knowledge here :lol:

Andrew
 
Aushiker said:
If you are ordering from Paul, I would with hindsight :oops: talk to him about making up a suitable length lead from the motor back to the battery. If doing this I would have the connection at the battery end to make removal of the battery easy. In my case I didn't so I simply cut off the connectors that came with the battery and motor and replaced them with Anderson Power Pole connectors (45 amp) and made up my own made-up power wire to the motor using 12 AWG wire.

I asked him to make a 2.1m battery cable. How did the speed sensor cables fit on your bike? I need 1.65m from motor to rear wheel or 1.1 m to one of the front wheels.

That mount thing for your front light, where did you buy that?
 
idar said:
I asked him to make a 2.1m battery cable. How did the speed sensor cables fit on your bike? I need 1.65m from motor to rear wheel or 1.1 m to one of the front wheels.

Mounted to the front wheel. I had to get an extension cable from GreenBikeKit. Thanks also for reminding me that I forgot to mention this in my blog post.

That mount thing for your front light, where did you buy that?

That is a Bacchetta One Arm Bandit (OAB). TerraCycle do an alternative mount, the Multi-purpose mount so a couple of options there. I had to drill my OAB to take the European mount that comes on the Busch & Muller light.

ACM031_MED.jpg


Andrew
 
ScooterMan101 said:
Is there a youtube video on how to install the Bafang BBS01-02 ?
None I've seen, but even with the oddly translated instructions it's very easy. Just a matter of having the appropriate bike tools and going slow. First build took me 2-3 hours. Second build about an hour. Oddest part was the threading of the BB and pedals. I had forgotten directions but found the info by google. The hardest part was getting the grips off the bars until I used my compressor to blow them off. Careful one was a missle and just missed my porch window. :oops:
 
Colour me embarrassed. :oops: Never saw anything about the need to hold power button down. My CA3 comes on as soon as I switch the battery on. As everyone says quality from Paul, well I have to include Grin and Ezee in that statement as well.

Cheerio and thanks :D
 
Fishy1 said:
Colour me embarrassed. :oops: Never saw anything about the need to hold power button down. My CA3 comes on as soon as I switch the battery on. As everyone says quality from Paul, well I have to include Grin and Ezee in that statement as well.

Cheerio and thanks :D
I actually had a display faiure and had the new display within a week from Paul. Impressive customer service. I was pleased to read someone else made the same mistake I did. It took me several hours to realize I wasn't reading carefully enough.
Lucky daughter!

Enjoy,

Tom
 
Aushiker said:
Kepler said:
Just checked out your blog. Wow, great job so far. Look forward to seeing the finish product. It should make a great reference site. 8)

Thanks. The dumb newbies approach to an ebike conversion ... counters all the technical and skilled knowledge here :lol:

Andrew
Without the help you both provided I would have had a miserable time. Thanks to you both for all you've given back!

Tom
 
I just measured the efficiency of my Bafang BBS01 250 W 36V. I took the Powertap rear wheel from my road bike and installed it on the Bafang bike and used a Watt's Up to measure electric input. I rode out to a stretch of road with varied terrain and rode 4.34 km down the road, turned around and went back the same way to measure the average power input and output.

Distance: 8.67 km
Average power output: 218 W
Average power input: 280,74 W
Time: 17 minutes 11 seconds
Electric energy converted: 80.4 Wh

This calculates to an average efficiency of 77.65%. Pretty much what I expected.


I also did a test to calculate the torque the motor was able to put out. I used fourth gear as I climbed a hill. The battery was pretty close to empty, but torque is a function of current, and the controller limits the current to 15 A as long as the battery can deliver that much, so it should be the same. The RPM number is also based on the assumption that the circumference of the wheel is 2100 mm. I may do a new reading some other time with a fresh charge and a cadence sensor, but it should be pretty close now.

Output power: 396 W
Speed: 19.1 km/h
Gear ratio: 46/19

This translates to:
Rear wheel RPM: 151.59 rpm
Chainwheel RPM: 62.61 rpm
Torque: 60.4 Nm at the chainwheel


I rode at midnight in the midnight sun.
 

Attachments

  • el21.jpg
    el21.jpg
    97.3 KB · Views: 2,877
tomjasz said:
Fishy1 said:
Colour me embarrassed. :oops: Never saw anything about the need to hold power button down.
I was pleased to read someone else made the same mistake I did. It took me several hours to realize I wasn't reading carefully enough.
Same.
 
I ordered a bbs01 some days ago. Still haven't recieved it.

But I am about to order a turnigy wattmeter aswell. What is the easiest and cleanest way to connect this to the kit? Where do I place the wattmeter?
 
fingret said:
I ordered a bbs01 some days ago. Still haven't recieved it.

But I am about to order a turnigy wattmeter aswell. What is the easiest and cleanest way to connect this to the kit?

These three threads at Pedelec should answer all your questions and more :)

Building the Shunt: http://www.pedelecs.co.uk/forum/threads/the-best-value-wattmeter.16869/

Instructions on wiring it - http://www.pedelecs.co.uk/forum/threads/measuring-battery-charge.15950/

Wiring diagram - http://www.pedelecs.co.uk/forum/threads/current-best-way-to-monitor-battery-time-left.17819/page-2#post-220132

Andrew
 
Great news for the most reliable reseller out there. Cell_Man has stock!

http://em3ev.com/store/index.php?route=product/product&path=36&product_id=166

"Bafang 48V 750W kits are now available with the new 25A BBS02 controllers, they will arrive tomorrow 2nd July. You are welcome to place an order through the site, the listing is enabled."
 
tomjasz said:
Great news for the most reliable reseller out there. Cell_Man has stock!

http://em3ev.com/store/index.php?route=product/product&path=36&product_id=166

"Bafang 48V 750W kits are now available with the new 25A BBS02 controllers, they will arrive tomorrow 2nd July. You are welcome to place an order through the site, the listing is enabled."

I am not 100% but will this battery(Norminal 20A) be ok for 25A BBS02

http://www.ebay.com.au/itm/131040922792?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

High capacity 48V15AH lithium iron phosphate battery parameters
Battery pack size: 13.5x16x26.5cm
Battery pack weight: 8kg
Battery capacity: 15AH ± 1%
Charging cut-off voltage: 58.5V
Discharge cut-off voltage: ≤ 45V
Nominal discharge current: 20A
Instantaneous maximum discharge current: 30A

Rated charging current: 5A

Maximum charge current: 8A
 
Sorry, wrong guy to ask. I'm sure you're mates will be along anytime to clear it up for you.

T
 
tahustvedt said:
The battery was pretty close to empty, but torque is a function of current, and the controller limits the current to 15 A as long as the battery can deliver that much, so it should be the same.
Not really, 1V@15A won't give you the same torque as 100V@15A. :wink:
 
Melbourne said:
tomjasz said:
Great news for the most reliable reseller out there. Cell_Man has stock!

http://em3ev.com/store/index.php?route=product/product&path=36&product_id=166

"Bafang 48V 750W kits are now available with the new 25A BBS02 controllers, they will arrive tomorrow 2nd July. You are welcome to place an order through the site, the listing is enabled."

I am not 100% but will this battery(Norminal 20A) be ok for 25A BBS02

http://www.ebay.com.au/itm/131040922792?ssPageName=STRK:MEWAX:IT&_trksid=p3984.m1423.l2649

High capacity 48V15AH lithium iron phosphate battery parameters
Battery pack size: 13.5x16x26.5cm
Battery pack weight: 8kg
Battery capacity: 15AH ± 1%
Charging cut-off voltage: 58.5V
Discharge cut-off voltage: ≤ 45V
Nominal discharge current: 20A
Instantaneous maximum discharge current: 30A

Rated charging current: 5A

Maximum charge current: 8A

It's not ideal, but it would work, based on the specs. Ideal would be a battery rated for at LEAST 25A continuous.
If you don't ride WOT that much, it would probably suffice.
Expect some voltage sag with that battery though.
In contrast, my 20C continuous rated LiPo, 5AH pack can discharge a theoretical 100A.
 
rp3 said:
tahustvedt said:
The battery was pretty close to empty, but torque is a function of current, and the controller limits the current to 15 A as long as the battery can deliver that much, so it should be the same.
Not really, 1V@15A won't give you the same torque as 100V@15A. :wink:
Yes it will. Torque is a function of current.
 
So a 15W input will provide the same torque output as 1500W input?

One of us is confused :lol:

My understanding is that if you left the current the same but doubled the voltage, theoretically you will double the motor speed and double the torque.
 
60 Nm at 15W is impossible in practice because the controller and motor can't operate at that low RPM, and the battery can't deliver any current it if it's drained that much. 60 Nm at 15 W is theoretically possible, but not with the Bafang. It makes little difference if the battery is half drained or full though. The difference between a half drained and full battery is in how high rpm the unit can produce max torque.

60 Nm at 15 W is 2,39 rpm.

Any given motor can't produce more torque than max no matter how much power it uses, because that would take more current than it can handle, (or a different gear ratio in the case of the BBS01, which is why a mid drive is better than a hub drive). More power means it has to spin faster instead of producing more torque. The unit that described the rpm per volt is called Kv, and is well known, but there's another unit for torque per amp, Kt. Power in a spinning motor is the result of torque multiplied by rpm.
 
Back
Top