Adrian's Bafang BPM Hardtail MTB

[Kabbage]

Adrian, in an earlier post, you show a screenshot with a lot of controller parameters for setting up.

I am planning on running my new bike without a CA as well - I have an Infineon controller from ebikes.ca. Is it possible to 'program' my controller too, without a CA? What software are you using to talk to the controller? What cable do you use (and where do you connect it?). Are you able to set a current limit like this? I take it the settings get stored in the controller somehow?

 

[adrian_sm]

Yep all the settings you saw listed can be adjusted on the controller, just need the right software, cable, and connection to the right pins on the controller. I am not certain of the exact boards in the ebikes.ca controllers, so you will need to crack open the controller and have a look on the board to see what model it is.

Mine is an EB306.
I programmed it using this software: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=27927
I had a bit of trouble getting the programming cable right, as mine was wired for the older EB2xx controllers, so I had to remap some pins, documented here: http://www.endless-sphere.com/forums/viewtopic.php?f=2&t=45545&

You should be able to buy the correct cable for your controller from Lyen ($15), Keywin, or possibly ebkies.ca.

BTW I have reprogrammed my controller for much lower amps now. At first I just cranked things up to make it a blast to ride, but found myself always having to be gentle on the throttle to either avoid a violent hit of torque or to try and only give a gentle assist at times. Much harder to dial in than a direct drive hub. I am also used to my friction drive and the electroncis I designed that smoothly engage the drive and have a couple of power levels I can choose on the fly while riding. So for now the compromise is lower amp limits, to keep me fit, and reduce the throttle hunt. Made me really wish for a torque rather than speed based throttle/controller. Alternatively if I could mod the controller to adjust the current limit on the fly that might be good enough.

 

[adrian_sm]

I was typically getting ~25km from the 15s5Ah battery, using about 4.5Ah, but this was riding pretty conservatively.
Since my work commute was 15km each way, I occasionally was running out of juice.

So I built a new battery using:
6x 5s5Ah Turnigy 20C packs, configured in 15s2p.
1x section of PVC drain pipe ~100x50mm section
2x pieces of EVA foam from Clark Rubber

The EVA foam was cut ~5mm larger than the internal section of the PVC tube, and jams in the ends. This effectively seals the ends, seals the wire exit, and provides some compliance as I jam it in to the frame on my bike. The I made a small bracket that lifts the bottom end of th battery to ensure clearance with the chain ring, and stops it falling out sideways. A small shelf on the bottle mount to stop the battery rolling, then velcro straps to hold it in place.

Should be all water tight, and I could still add the old saddle bag battery in parallel if I wanted for 63V15Ah.
Also a bit more suitable for off-road once I refine the retention method a bit.

Here are the photos:

 

[adrian_sm]

I have been riding the same route on my various bikes, and the efficiency results were quite interesting.

Ride is ~15km hilly route on roads.

On my road bike (no electric assist) I average 21-22kph.
On my road bike with the Commuter Booster assist, I average 26-27kph, and use 14Ah at 5s, so about 260wh for the round trip.
On this Bafang BPM bike, I was averaging similar 26-27kph speeds, but ran out of juice at about the 25km mark with 4.5 Ah of the 15s battery, so 250wh. Then riding the last 5km unassisted (with a couple of steep hills) brought my overall time slightly slower than my road bike times.
If I rode more conservatively with the throttle, then my average dropped to about 24-25kph and I can make the round trip, but you are constantly thinking about conserving the battery, rather than just enjoying the ride.

What did I learn:
1) Road bikes are much more effecient to ride.
2) Always size your battery pack to suit the power level you want, and the distance you plan to ride without charging, on the Bafang BPM bike.
3) The Commuter Booster on a road bike, is much more efficient and fun to ride if you still like to feel like you are pedaling, and is still fine to ride if you do run out of juice.
4) If you don't really care about feeling like you are contributing with your pedal effort, and are happy to use the throttle all the time, the mountain bike + geared motor are great.
5) I really don't want to ever run out of battery with the geared hub motor mountain bike if there are any hills around. It sucks to pedal on hills, but is fine on the flat stuff.
6) The CB road bike is definitely loader than the hub motor bike, so is not stealthy.

 

[adrian_sm]

The white battery tube was a bit too in-your-face. So I whipped out the sewing machine, and made a little black stretchy waterproof fabric cover for it. Zip runs underneath the downtube.

Looks very tidy now.

 

[Kepler]

You're a man of many talents Adrian

I get a similar efficiency on my Super Commuter, probably about in the middle of the two bikes you are comparing. I have a 28km commute each way to the city. Typically use 220W/hrs going in and about 260 coming home with and an average speed of around 28kph. Charge at each end.

Actually converting the Super Commuter back to Friction drive over the next couple of weeks to carry out some endurance testing of my latest design. Should be interesting to compare efficiency against the overvolted SWXH geared hub setup.

 

[adrian_sm]

Thanks for that.

Now that I have the battery capacity I'll repeat the BPM runs with similar riding style to the road bike. Then I might do the same and rip off the hub motor and slap the friction drive back on. I always thought there wouldn't be much between a geared hub and the friction drive, but we will see.

P.S. Sewing is definitely not one of my talents, took way too much head scare hong and looking up instructional videos just to thread the stupid machine. I should have just waited until the wife was back from Sydney... but I am just too impatient.

 

[adrian_sm]

Did a full speed commute now that I have the bigger battery pack.
30.6 km round trip
15s6.5Ah for 360wh
11.8 wh/km
average speed = 28 kph.

Quite a lot more than the road bike with commuter booster
30.6 km round trip
5s14Ah for 260wh
8.5 wh/km
average speed = 26-27 kph

That is a huge difference, nearly 40% more watt-hours. I expected it to be much closer. Really need to repeat with the commuter booster on this mountain bike for a fair comparison.

 

[adrian_sm]

Clutch has seized in the motor. This might explain some of the poor efficiency.

 

[Samd]

Interesting stats Adrian. Are you running a code 11 or Code 10?

 

[adrian_sm]

Code 12 on 15s. But my seized clutch and a strange sound from the motor means the stats are dodgy.

 

[adrian_sm]

Hmmm. Managed to free up the clutch but the strange scrapping type sound remains.
Guessing it is some axial misalignment causing the planets to touch something every so often.

Great.

Might be a good time to convert back to friction drive while I sort it out.

 

[adrian_sm]

Took the bike for a ride.
- planets rubbing at first
- seemed to go away
- clutch froze again
- efficiency stats still suck at ~12wh/km at a modest 500w and 40kph cruise speed

Guess ill get a new clutch and pray the rubbing issue was related, but I am not so sure...

 

[adrian_sm]

Converted the bike back to friction drive.
Same tires, same pressures, same trip.

~30km round trip
MTB Friction Drive = 260wh, 27kph, ~8.5wh/km
MTB (dodgy) geared hub = 360wh, 28kph, 11.8wh/km
Roadbike FrictionDrive = 260wh, 26-27kph, 8.5wh/km

I was pedalling a bit harder on the MTB, but really surprised I got essentially identical efficiency compared to the road bike comparing the friction drive stats.
But something is definitely wrong with the BPM results. On averaging using 100w more, that is a lot of unwanted drag....

 

[adrian_sm]

Took this bike in BPM hub motor guise on a off-road group ride.
Details here: http://www.endless-sphere.com/forums/viewtopic.php?f=25&t=53202&start=50#p800840

Pic of my bike with it's nice little fabric cover for the battery, next to a Stealth Fighter.

[youtube]vcREtj-wirc[/youtube]

Even went up "The Wall" a 1 in 2.5 grade hill, that is part of the old Templestowe Hill Climb.
The Bafang BPM made it up with some healthy pedalling first go. Controller was set at 25 Battery Ampp, 65 Phase.
The stock Stealth Fighters that tried took a couple of attempts to get up, but made it with a decent run up.

 

[John Bozi]

I was typically getting ~25km from the 15s5Ah battery, using about 4.5Ah, but this was riding pretty conservatively.
Since my work commute was 15km each way, I occasionally was running out of juice.

So I built a new battery using:
6x 5s5Ah Turnigy 20C packs, configured in 15s2p.
1x section of PVC drain pipe ~100x50mm section
2x pieces of EVA foam from Clark Rubber

The EVA foam was cut ~5mm larger than the internal section of the PVC tube, and jams in the ends. This effectively seals the ends, seals the wire exit, and provides some compliance as I jam it in to the frame on my bike. The I made a small bracket that lifts the bottom end of th battery to ensure clearance with the chain ring, and stops it falling out sideways. A small shelf on the bottle mount to stop the battery rolling, then velcro straps to hold it in place.

Should be all water tight, and I could still add the old saddle bag battery in parallel if I wanted for 63V15Ah.
Also a bit more suitable for off-road once I refine the retention method a bit.

Here are the photos:

any pics of the batteries sitting half way in the pvc? I see 5s which has just really made me sad. I was looking at getting less capacity 6s than my current 5.8 just to fit the pvc.

if the blue cheap 6s dont fit I wonder if the zippy yellow ones would (although Ive seen them puff on other people)

 

[adrian_sm]

PVC Internal dimensuins
51*102mm
3mm radius

6s*5000mah turnigy 51*53mm
=> no room for wiring.