New Bafang Crank-Drives

[Geebee]

For anyone wanting to mod brake switches to use with different levers etc.
If you cut the lead off the provided hand brakes you will find a red (5v), black (0v) and blue wire (sensor output) , if you short blue and black it activates the brake switch cutting off the motor.
So if you wish you can use a micro switch or reed switch to activate the brake cut off.

 

[skyungjae]

For anyone wanting to mod brake switches to use with different levers etc.
If you cut the lead off the provided hand brakes you will find a red (5v), black (0v) and blue wire (sensor output) , if you short blue and black it activates the brake switch cutting off the motor.
So if you wish you can use a micro switch or reed switch to activate the brake cut off.

That's a great idea. I wonder if it'll work with a horn button.

 

[John Bozi]

can the bb02 run without the lcd screen and brakes?

And any other sensors?

I'm interested in the idea of running it on my bike in addition to the hub motor.

don't want any more clutter than a small mid drive and the battery to run it.

would be cool to have it to take all the 0-20kmh take offs in granny, give the hub a breather, or a bit of a hand on steep hills.

 

[cwah]

I have error 21. It s an error with the brake sensor. The sensor light on red when the wheel is spinning so it receive a signal.

However, i can't see anything on my lcd.

What can i do?

 

[Geebee]

I have error 21. It s an error with the brake sensor. The sensor light on red when the wheel is spinning so it receive a signal.

However, i can't see anything on my lcd.

What can i do?

Does the speed sensor light flash when the magnet goes past?

 

[cwah]

Yes it gets red

 

[Geebee]

Only thing I can suggest is unplug and reconnect the sensor lead incase it is not making a good connection, also visually check that all 3 pins are not damaged whilst its apart.

 

[RayGo]

There is another way to modify the brake switch with existing hydraulic or other brake levers. When I last e-mailed with Paul at em3ev.com earlier this month, he said he was carrying the new brake sensors that work with hydraulic brakes that are plug and play with the BBS02 kits. When I asked for more details, he said they simply stick on your existing brakes levers so I'm assuming these are the hall sensors mentioned in other threads on the ES forums. It appears to be the same as the brake sensor at BTN on AliExpress for $15 plus $15.62 shipping:

http://www.aliexpress.com/store/product/Good-quality-electric-bike-hydraulic-brake-sensor-brake1/705369_1723712251.html

I'm planning on using just one such sensor on the underside of my left hydraulic brake reservoir once I remove the front derailleur shifter. The sensor requires about a 1" flat area to stick to. Paul does not have it listed separately on his website but said to order the HWBS Sensor and then specify that you want the sensor for the hydraulic brakes. Cost is $12.50 plus shipping from em3ev.

I'm more comfortable with having a kill switch on the brake rather than a separate kill switch to reach for. However it is a best to have any sort of kill switch and a lot cheaper at about $6 and using the mod suggested by Geebee.

 

[astmacca]

Just bought one of these on eBay and installed today.

https://www.dropbox.com/s/i0h605txe9qu4v5/wattmeter.JPG?dl=0

Mounted it in a little sealed food container on the seat tube with cable ties and the holes siliconed up to keep it dry.

Cheap Chinese made Watt Meter. Installed inline between the battery and motor. Checked the voltage reading on this unit against a multi-meter and was only 0.1V difference so seems pretty accurate on that score at least.

Actually installed it while i was at work today since i could use the soldering gear in our workshop. Rode home as normal and checked the figures on arrival.

For 9.2km i used 44.9wH. Max draw was 18.4 amps.

This is on a 48v / 500W BBS02. Assist level 3 today which is 30% current and i use the throttle at a couple of intersections on hills to help start off. I do use the gears and i pedal fairly hard.

Anyhow, question.

Has anyone with better electronics knowledge than me (and that is just about everyone) used one of these and how have they found them? I'm assuming at the moment that its accurate since the voltage i checked was very close. Also, the controller is limited in programming to 18A and thats not far off what the meter said it maxed out at.

Am i safe to assume accuracy on that basis or is there something obvious i'm not taking into account??

I'm going to take it on a longer, about 26km ride tomorrow and see how it goes.

Also, thinking of hanging up the bike off the ground and jamming the throttle open to run it till it hits the low voltage cut-off (from a freshly charged state) to get a figure on how many wH my particular battery has on offer. Anyone see any flaws in that? Apart from problems of the back wheel hits the ground while i'm doing the test.

 

[cwah]

Only thing I can suggest is unplug and reconnect the sensor lead incase it is not making a good connection, also visually check that all 3 pins are not damaged whilst its apart.

The speed sensor is integrated with the motor. I can't unplug it :/

 

[Geebee]

@ astmacca, Yes I can think of one reason not to do the test, it will be running for ages as off the ground the load will drop to very low current usage due to almost no load.
I have something similar although the tiny picture it is hard to be sure
Mine is pretty accurate, your Wh look about right with a reasonable amount of pedaling.
Does your charger show amp hours charged? as that would give you a rough guide.

 

[Geebee]

Only thing I can suggest is unplug and reconnect the sensor lead incase it is not making a good connection, also visually check that all 3 pins are not damaged whilst its apart.

The speed sensor is integrated with the motor. I can't unplug it :/

Are we talking about a BBS01or 02?
All the ones I have seen including mine have a fly lead that screws onto the connector on the sensor.

 

[astmacca]

@ astmacca, Yes I can think of one reason not to do the test, it will be running for ages as off the ground the load will drop to very low current usage due to almost no load.
I have something similar although the tiny picture it is hard to be sure
Mine is pretty accurate, your Wh look about right with a reasonable amount of pedaling.
Does your charger show amp hours charged? as that would give you a rough guide.

They seem very common so i think they are prob the same. Nope, my charger very basic, two LED's only.

Was going to put it in high gear, but yeah, the issue of no load could be a prob. Will thunk on that.

 

[cwah]

Only thing I can suggest is unplug and reconnect the sensor lead incase it is not making a good connection, also visually check that all 3 pins are not damaged whilst its apart.

The speed sensor is integrated with the motor. I can't unplug it :/

Are we talking about a BBS01or 02?
All the ones I have seen including mine have a fly lead that screws onto the connector on the sensor.

I have a BBS02 and it's integrated

 

[tungsten2k]

I have a BBS02 and it's integrated

Picture ?

-=dave

 

[astmacca]

Yup, hanging it up and running in high gear was only drawing about 1.7 amps. Did it for an hour and yup, this would take ages

Will have to ride the sucker till the battery gives out (or at least hits the 41V LVC).

Oh, Damn it all! I guess that means riding around on high assist for a bit??

 

[John Bozi]

Yup, hanging it up and running in high gear was only drawing about 1.7 amps. Did it for an hour and yup, this would take ages

Will have to ride the sucker till the battery gives out (or at least hits the 41V LVC).

Oh, Damn it all! I guess that means riding around on high assist for a bit??

now your sounding like less of equipment junky

I often wonder about myself and many of the people here on es whether they enjoy riding less than building....

Personally it's 50/50 the zen art of emtb & slaying the mountains

 

[John Bozi]

can the bb02 run without the lcd screen and brakes?
And any other sensors?

I would like to know if I can just run the throttle and controller/motor. (would add a kill switch as it sounds like the throttle has issues)
Just to be annoying and bump my own question, could anyone give me a

no or yes?

all the online sites don't explain the details of how this runs.

I have read manuals too

if that gives me more cred. to deserve an answer...

 

[Geebee]

You will need the LCD which also has the PAS and on/off switch unit attached to it permanently, also the speed sensor although that can be setup on the ring on the cranks if you wanted to but you lose accurate speed indication.
I suppose you could mount the lcd in the battery bag if you want it invisible?

 

[astmacca]

now your sounding like less of equipment junky

LoL! Its all a means to an end but fun.

So....did a ride this morning. Its a normal circuit i do with a few undulations in the first half into a headwind, with the second half flat (until the last 2.5km hill) with a tailwind.

26.3km on PAS 2/3 used 99.3 wH for 3.78 wH/km

Then hung the bike up and let it run for an hour. Sucks, boring, and would take ages.

So, did basically the same ride as this morning with a couple of detours but on PAS 8/9 and liberal use of throttle.

29.9km on PAS 8/9 used 262.5 wH for 8.78 wH/km.

Battery effectively drained about 1 km from home. It was low enough so that it was cutting in and out depending on if i was pedaling or not.

Then about 50m from home, BMS cut the power from the battery completely. This reset the meter of course.

So, total usage extracted from my battery (EM3ev, 48v, 11ah, Samsung 29E cells, frame pack) for the whole day from fully charged was:

440.9wH / 11.031 AH as measured on my meter.

One thing i was interested in was how do wH used relate to the battery level on the Bafang display?

I stopped and took notes at various stages. Pen / Paper = poor mans data logger.

This isn't definitive as its only data from 1 ride, but i thought it may be worth sharing.

Fully charged this morning with 4 bars @ 54.34V

Started this arvo's battery draining ride with the display on 4 bars at rest and a voltage of 49.86V, wh used @ 178.4wH.

Went from 4 bars on the display to a consistent 3 bars on the display at rest @ 47.65V, wh used @ 244.0wH.

Went from 3 bars on the display to a consistent 2 bars on the display at rest @ 45.81V, wh used @ 336.6wH.

Went from 2 bars on the display to a consistent 1 bars on the display at rest @ 44.03V, wh used @ 400.6wH.

Motor starting to cut in and out as voltage sags under load, with a flashing battery outline when running, and 1 bar at rest @ 42.67V, wh used @ 440.9wH.

BMS cut the power off completely soon after the voltage sagged under load far enough. Turned the power on and off again to reset and after a couple of minutes to stabilize the meter was reading 42.41V.

Low voltage cut-off programmed in the motor controller is 41V, and i think the BMS is programmed for a 40V LVC.

I think riding at high assist levels until i hit the LVC is the best way i have to test actual battery capacity. Going to have to try this again, but not too often.

High assist is addictive.

And i dont want to do full cycles on the battery too often.

Question for people out there. I thought that wH from a battery could be calculated by Voltage x Amp Hours??

Using Paul's advertised figures that's 46.8V x 11AH = 514.8 wH. I get 440.9 wH measured.

However, i also measured 11.031 AH, which is bang on the advertised capacity of 11AH.

I'm not upset about this as the way i ride i reckon i should get a reliable 75-85km out of that battery. But it may mean i am not understanding something here about battery capacity??

 

[tungsten2k]

W•Hr = f(t) = Vt•At (lim t => 0)

Look at the data sheet of the 29E and you'll see that the mfr rated capacity is at low current draw. Lots of factors influence the quantitative data you're obverving, not the least is the sample rate of your equipment. Is your delta t (measurement) actually approaching zero ?

-=dave

 

[astmacca]

Is your delta t (measurement) actually approaching zero ?

Looked up the manual. Sample time is 400ms.

Look at the data sheet of the 29E and you'll see that the mfr rated capacity is at low current draw

ok, so at higher current draw we see less capacity??

The curiosity for me is that the AH measured was what i expected but the wH wasn't.

 

[Geebee]

The battery voltage is not constant you started at 54.34v and low voltage cutout was at 41v, so the wh would be dependent upon how long each voltage was maintained, throw in voltage sag etc. your gauge would be the more correct wh as it was taken over the real world voltage curve.
Nice result getting almost the exact rated Ah out of the battery.

 

[astmacca]

your gauge would be the more correct wh as it was taken over the voltage curve

.

Yup, i'll go with that 440 wH as my capacity for working out if i can make a distance. Given the lack of sophistication of my equipment in this context, i'll take measured over modeled no probs.

And no doubt sometime i will still get caught short and pedal home the old way.

Nice result getting almost the exact rated Ah out of the battery.

I'm very pleased with this as a piece of kit. I think it performs as well as can be reasonably be expected.

Curious now though about wH / km?

With the programming i run and my riding normal habits i seem to be getting about 4 - 5 wH/km "fuel economy".

Hammering it ( for me), by using 85 - 100% current on PAS ( 15 - 18Amps draw) and being liberal on throttle use i'm getting about 9wH/km.

Hmm.. at that rate 440wH / 9wH/km is a range of 48km. Noice.

Had a look in this article:

https://www.electricbike.com/watt-hours/

and they are saying real world use is around 20wH/mile ( 12.4wH/km). That seems a lot??

Most of the bikes in that article are Hub drives though. Are Mid Drives (that use the bikes gears, i change gears a lot actually) that much more efficient??

 

[KINNINVIEKID]

My BBS02 uses an average of around 15Wh/mile so I can get 50 miles out of the 16Ah batteries.
Mt 1000Watt Dillenger front hub uses around 30Wh/mile so usually gets me 16 miles on the 10Ah battery.
Guess which one spends most of the time locked in the garage?