messing around with ebikes

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Anyone got any experience bodging up e-bikes with BLDC hub motor at subsystem level?

I have developed some broad theories on the arrangements so far, based on my vast experience of :
guessing a diagnosis of failed and unidentifiable controller on one problem bike, taking a punt on something with similar power/voltage rating on ebay, getting it home and bodging it in. these are my thoughts:
where I refer to things like "usually" this is informed solely by amazon/ebay windowshopping.

I contend that A, B, D, & F are very likely to be functionally compatible between all products, therefore you CAN use any controller to make a hub motor drive with proportional throttle control ergo, a working ebike.
I further contend that refinements (E,G) such as pedal assist and operational display & keys are less compatible between components.

would welcome comments from other experiences


A. Hub Power: Essential.: the motor requires a 3-phase power supply (delivered through.... 3 conductors). Simple to locate these on any given replacement controller module.

B. Hall: Essential: within the motor module is a "hall sensor" with 6 wires, which follow a standard colour code between the controller and the hub. within this bunch of 6 wires are 3 phase sense lines, which it might be possible to get wrong, so you either swap these 3 wires until success, or....

C. Self learning: (not essential) some controller modules have a "self study" or "self learn" line pair, which you are supposed to join together briefly, and start the controller, these then sort out the hall sense lines autonomously, thereby getting round the possible ambiguity in my point B above.

D. throttle: Essential: there is a thumb throttle with 3 conductors, ground, Regulated Voltage (4.5V?), and command signal. Thumb throttle wires goes direct to the controller, should be fairly easy to identify the lines from data on the PCB print or the very limited literature associated with any replacement controller.

E. PAS (not essential?): Pedal Assist sensor . matches up to some proximity sensor (?) on the pedal crank, and an optional extra function. 3 wires (4.5V, Gnd & signal) on the controller. Assist or Non-Assist may be different modes of controller operation which require an operational display/keys to work properly.

F. Brake (not essential): seems to be just a switch to interrupt power delivery to the BLDC motor whenever you pull a brake lever. dont think it provides any braking power within the hub? 2 wires (one signal line & gnd) on the controller

G. Display (not essential) ..... usually comprises of a LCD and 3 keys.... but limited standardisation of wiring and possibly not all displays are compatible with all controllers? I note RxD & TxD on my failed controller, associated with the display cable, so probably some serial data arrangement which could have differing protocol nuances between mfgs - although this seems unlikely because all handlebar arrangements are very similar ( 3 keys UP/DOWN/ONOFF + similar display data) Anyway, I couldnt get the bike's original display to work properly with the replacement controller.


I think I am missing something, possibly a Controller Module Enable line, because I noted that whilst I couldnt get the display to work properly, I couldnt get any motor response if I didn't have certain display lines connected, but couldnt work out what was going on. I did not have to have the display lit-up for the motor to drive.

The display & switches appear to offer the possibility of:
monitoring energy remaining. this is a pretty desirable function tbh. (which is only thru simple voltage measurement of battery+ve line which is used for powering the display).
power ranges (1-7). I deem this is an unnecessary frill
odomter / speed (unnecessary frill)
pedal assist or non-assist modes?

Anyway it was all going reasonably well with my £20 replacement generic controller (could get proportional drive to the hub motor anyway) until I accidentally placed it down onto a piece of solder and now it's dead.

After the swearing had died down I condensed my waffling views above into this:
you can make any similar controller drive a BLDC hub with any throttle, but if you want a decent repair with operating display/keys etc, then you should get a controller with its compatible handlebar display. so now Ive ordered a controller with a display kit for £35.
 
The display & switches appear to offer the possibility of:
monitoring energy remaining. this is a pretty desirable function tbh. (which is only thru simple voltage measurement of battery+ve line which is used for powering the display).

You can do better than that, with a little display which monitors actual charge, and discharge current. It then applies a pre-settable percentage, to allow for the inefficiency. I have such a little panel display, maximum voltage 60v, maximum current 30amp. It cost me £8-ish on Aliexpress.
 
All I can say, three e-bikes wife's mid-engine, mine and sons rear hubs, are all very different, 36 volts and 48 volts, will start helping within a yard and need to do width of road before cutting in, have throttle and have no throttle, limited to 16 MPH and will still help at 22 MPH, even the way the assistance is delivered.
Mine with this display 1774177917103.pngSeems to have setting options, not quite matching my bike, but yours may have simular.

NoMod codeNotes:- Found similar controller so seems to follow nearly same but not quite.
defaultnew
01000 1 Possible display brightness
02 MPH 000 1000 2 Says Km/H or MPH in Mod number window.
030048 Possible battery voltage
040010 Possible sleep time
0505 Possible power assist
06026.0 Possible wheel diameter
070017 Possible speed measuring magnets in motor
080100 Possible speed limit if speed sensor
09000 0 Possible Start value of power assist
100002 Possible Handle bar control 0=P 1=T 2=P+T
110024 Possible Sensitivity level
120003 Possible Boost sensitivity
130005 Possible Boost start strength
140012 Possible current limiting control
15039
160000 Possible Battery under voltage valve
1700003.6 miles Likely allows one to zero the odometer count?
 

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