Shenzhen (ecrazyman) Controller Information

[Knuckles]

So far the only reliable post on overclocking is 27-mhz. Not bad for a 20-mhz MCU.
Keywin needs to get the 40-mhz MCU if the PUMA solution is to reach 72V.

I recommend crystals for testing. Not a signal generator. But it is all pointless until we get a faster MCU.

Eventually we can clean up the code and run it even faster (as may be req'd).

[shinyballs]

hey knuckles,
not sure if you read my last question.... I'll repeat again -

Is the Bafang geared motor available in other gearing configurations? i.e. for high speed

[Tiberius]

Tiberius,
Did you note the battery ( PSU) current in your test?

No, sorry. It would not be a reliable result anyway - the PSU's have digital displays and don't react well to varying currents. Also I have found in the past that the current readout is not accurate at low levels.

Nick

[Tiberius]

The actual processor is a bit of a mystery as the number does not come up on any searches.
Supposedly it is the same as a PIC16F72, rated for 20mhz.

Hi fechter,

Yes, I saw you posted that earlier and I worked on that assumption for the clock connections and to check the supply volts.

Good idea on the flashing lights as well.

Nick

[Tiberius]

Clock test

condition
36 volts LVC enable
- LED blink 8 time and pause one

No Xtal or Resonator
- no blinking at all

16MHZ Xtal or resonator
- LED blink and pause about 5 times @ 30 second

27MHZ Xtal or resonator
- LED blink and pause about 8 times @ 30 second

It seems that MCU responses to Xtal or resonator speed
- It might be that proble from single generator acts as resonator for low frequency

I too tried the blinking light test proposed by fechter. I started at 16 MHz clock and went up insteps of 4 MHz.

One time I got to 48 MHz, 8 very fast flashes. I even managed to raise the volts above cut off, start and stop the motor and go back down below cut off and get back to the 8 fast flashes.

But another time, it lost the plot somewhere between 36 and 40 MHz and wouldn't recover until the power had been cycled.

I guess its the difference between what you can demonstrate in the lab and what you would go out on the road with. Clocking at 48 MHz has been demonstrated on one example in the lab. On the other hand, there is a question mark about reliability at 36 MHz. Personally, I would be wary of anything over 20-24 MHz without extensive testing.

Nick

[Knuckles]

hey knuckles,
not sure if you read my last question.... I'll repeat again -

Is the Bafang geared motor available in other gearing configurations? i.e. for high speed

A: No. I am not aware of different gearing (time for a gear mod?). But there is no need. Is there?
My guess would be a Bafang 2x2 at 72V and 2x30=60amps would be a 45 MPH e bike.

-B

[solarbbq2003]

bafang only make one gear ratio, but have different rpm motors, to suit from 16" up to 26", I think rpm no load varies from about 160rpm up to 320rpm ( bit of a guesstimate), not sure how they vary the rpm of motor, whether its number of poles, or something else.

[fechter]

I too tried the blinking light test proposed by fechter. I started at 16 MHz clock and went up insteps of 4 MHz.

One time I got to 48 MHz, 8 very fast flashes. I even managed to raise the volts above cut off, start and stop the motor and go back down below cut off and get back to the 8 fast flashes.

But another time, it lost the plot somewhere between 36 and 40 MHz and wouldn't recover until the power had been cycled.

Excellent test. 48mhz is really screaming for one of these. I agree that anything over 24mhz is 'iffy'. The maximum stable speed could be affected by temperature also.
Got liquid nitrogen?

[The7]

bafang only make one gear ratio, but have different rpm motors, to suit from 16" up to 26", I think rpm no load varies from about 160rpm up to 320rpm ( bit of a guesstimate), not sure how they vary the rpm of motor, whether its number of poles, or something else.

I would guess that they only change the no of turns per pole which is similar to Crystalyte gearless hub 4xxx/5xxx motors.

[solarbbq2003]

oh very interesting I didn't know that was all needed to vary rpm

[The7]

oh very interesting I didn't know that was all needed to vary rpm

Technically it is not correct.
It should be done by gear and/or no of pole-pairs if the same power rating is to be maintained.
The physical size of the motor (not including the gears) remains unchanged if it uses different gear ratio.
The physical size of the motor is (nearly) inversely proportional to the rpm if the same gear ratio is used (or if its gearless).

When the variation of winding turns per pole is used to vary rpm, it is done as an compromise so that no new mechanic part nor new structure is reqiured. Its aim is to achieve (nearly) the same top speed for different wheel sizes when using the same battery voltage.

Using Crystalyte motors as an illustration:
With an 36V battery
C404 on 16" wheel would give top speed on flat = 0.93 x 36 = 33 km/h
C406 on 26" wheel would give top speed on flat = 0.97 x 36 = 35 km/h
Both could achieve nearly the same top speed using the same battery voltage.
BEMF of the C404 = BEMF of C406 if "rpm of C404" = 6/4 x "rpm of C406".
The physical contruction of these two are identical except for the winding turns/pole.

[Knuckles]

I laced up my Bafang front hub (26" rim ... 216mm spokes ... perfection).
Ran it at 72V 20 amps on my old ana-log x-troller!
...
Like running a DeWalt "power tool"! I'm riding a freakin' torque wrench!
Completely different than a Direct Drive. Absolute Heaven! But very different.
I'll post all the pics here ...

Start with a 26" 36-spoke rim ...

Add 216mm spokes ...

Compared to a 500W 48V DD Grubee Motor (Bafang 250W 36V is less than half the weight but just as powerful) ...

And it comes with this neat'o torque washer ...

And these goofy protective caps! ...

Installed! ...

The test track ...

And the first test ride was great!
Bafang PMGR has no problem at 72V.
The motor ran a little warm (just a little).
As soon as my new 20-mhz resonators arrive I'll be testing at 30-amps!
And it freewheels like it's not even there! Much better freewheel than the DD.
(But different acceleration .. It kind-of 'ramps up' to speed. Not as responsive as DD. I need to test at 30-amps ... soon.)

cheers
Knuckles

[The7]

Without power, which one is more free to pedal?

[ngocthach1130]

those higher rpm bafang might be needed knuckles. I'm thinking of putting it in a 20" wheel.

[docnjoj]

Hey Knuckles! Hows the noise level ot the geared motor compared to the regular hub? I'm a quiet freak!
otherDoc

[oatnet]

Nice pics knuckles, thanks for posting. Anyone laced a rear motor yet?

BTW, I have had bad luck with torque washers, I would be very leery of them. The ones I used flattened out and helped march the front wheel out of the dropouts. Fortunately I was just turning in the street when I failed, at speed it would have been catostrophic. Check your bolts every ride until you can get to a torque-bar!

-JD

[shinyballs]

I wonder if a Kelly brushless controller works with the Bafang motor. With its insides fully potted, it may be difficult to test... Any brave soul up to it?

[Knuckles]

BTW, I have had bad luck with torque washers, I would be very leery of them. The ones I used flattened out and helped march the front wheel out of the dropouts. Fortunately I was just turning in the street when I failed, at speed it would have been catostrophic. Check your bolts every ride until you can get to a torque-bar!

-JD

Funny. The torque washers are not steel. It's an alloy of some type.
The washers won't really deform. They will most likely shatter on failure.
Bummer if that happens at 30 MPH.

But it looks tight for now ...

btw ... plenty of axle left to add a torque arm. In fact I have one laying around.

But I like living dangerously! Ha Ha

[Knuckles]

Hey Knuckles! Hows the noise level ot the geared motor compared to the regular hub? I'm a quiet freak!
otherDoc

It is a different kind of quite. You can hear the gears. But it is cool and not much different (decibels) than DD.
But definitely a different sound.
I kind of like it. With freewheel it is easy to maintain stealth.

When I gun it I'm riding a freakin 72V power drill.

[shinyballs]

Push either type motor too hard and, bammo! … Blown hall sensors. IMO the Bafang PMGR and Grubee DD motors should never be pushed beyond 72V & 30-amps. Even if you replace the wire harness with thicker phase wires (highly recommended btw. See ... viewtopic.php?f=2&t=4626), 2000W into the motor is about the max you can go without overheating the motor and blowing the hall sensors.
NEVER RUN THE BAFANG ABOVE 30 AMPS!

Hey, Maybe we should commission the Bafang Company to build a 5KW PMGR that we can push to 20KW!

Is running Bafang at 72V & 30-amps continuous?
I'm really looking forward on the revised Shenzhen controller. So, Keywin is presently working on it, will they be ready next month?

[voicecoils]

I wonder if a Kelly brushless controller works with the Bafang motor. With its insides fully potted, it may be difficult to test... Any brave soul up to it?

The smallest 72v Kelly (https://www.kellycontroller.com/shop/?mod=product&cat_id=22&product_id=152) 60A continuous, 100A maximum. You'd probably need to limit the current. 4kW+ would quite likely melt that motor eh?

USD$249 is a steep jump from $70 for the 72v 28A max ecrazyman one here: http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=300229589624

What does the updated one Keywin's working on address/do?

[aaannndddyyy]

After using the Ecrazymans 48volt 28amp controller with the 24 MHz 3 PIN CERAMIC RESONATOR, fitted to an Ezee sprint Brushless 350 watt motor for the last week. The throttle seems a little unstable at low revs, it stays at a stable speed for a couple of seconds then accelerates slightly for a moment then back down to the stable speed again it may be doing the same thing at higher speeds but isn’t so Noticeable, is this because of the resonator? Or perhaps a wiring problem, I have changed the throttle over with a different one with the same affect and checked the connections. By the way under no load testing this problem doesn’t show up.

[The7]

The smallest 72v Kelly (https://www.kellycontroller.com/shop/?mod=product&cat_id=22&product_id=152) 60A continuous, 100A maximum.

•Up to 60000 electric RPM. (electric RPM = mechanical RPM * motor poles)

60000 eletric RPM = 30000 rpm for 1 pole-pair ( 2 poles) = 500 Hz

Kelly controller has a max phase frequency of 500Hz

For Puma (with 16 pole-pairs and gear ratio 5:1),
the max hub rpm = (500 x 60)/(16 x 5) =375 rpm

For Bafang (with 10 pole-pairs and gear ratio 4.3:1)
the max hub rpm = 698 rpm

K-controller should be OK for Bafang motor.

[voicecoils]

The smallest 72v Kelly (https://www.kellycontroller.com/shop/?mod=product&cat_id=22&product_id=152) 60A continuous, 100A maximum.

For Bafang (with 10 pole-pairs and gear ratio 4.3:1)
the max hub rpm = 698 rpm

K-controller should be OK for Bafang motor.

Cool thanks. I don't quite understand this critical frequency business. I've just ordered the Shenzen 72v, 28a controller and Bafang PMGR. Controller was to cheap to pass up. I'll need to do a controller mod to solve the critical frequency issue? Any enlightenment appreciated, I'm not an EE but can solder

[fechter]

After using the Ecrazymans 48volt 28amp controller with the 24 MHz 3 PIN CERAMIC RESONATOR, fitted to an Ezee sprint Brushless 350 watt motor for the last week. The throttle seems a little unstable at low revs, it stays at a stable speed for a couple of seconds then accelerates slightly for a moment then back down to the stable speed again it may be doing the same thing at higher speeds but isn’t so Noticeable, is this because of the resonator? Or perhaps a wiring problem, I have changed the throttle over with a different one with the same affect and checked the connections. By the way under no load testing this problem doesn’t show up.

Strange. I don't think it would be caused by running at 24mhz, but who knows?

I could possibly be the voltage regulator is sagging and causing the 5v supply to vary.

If you can, measure the 5v on the throttle while this is happening (you know, duct tape meter, wires...).