Q128C hub motor part number explanation

[pajtaz]

Hello, does anybody know the explanation of the part number of the Q128C hub motor? It is Aikema produced motor purchased from BMS Battery. It should be 48V 500W 328RPM Q128C motor but I am interested in gear reduction ratio and any other motor characteristics that can be extracted from the part number.

There are two numbers:
AKM19072001002
BBA4816B

It looks like "48" in BBA4816B means 48V. I would guess that "1907" in AKM number indicates year (2019) and month (July) of production. But I am not sure and don't know about the rest. Does anyone know?

 

[Nealh]

4816 means 48v & 16" rim.
Only an assumption;
19 = Year so 2019
07 = Month so July
2 or 20 Day of month ?
01002 = Line number/construction number.

 

[pajtaz]

First one is definitely the serial number, with date of manufacture and serialized production number.

Looking at bunch of photos on BMS Battery website, I figured out that the "B" at the end means 48V, where "A" is 36V or 24V.

"16" being rim size makes sense but I was thinking it relates to what suppliers and manufacturers are calling RPM. "16" would be 328 RPM and "26" would be 201 RPM. These are the only two numbers that show up after voltage on the Aikema part numbers. It would make sense since on BMS Battery website, for example, they keep writing that "201RPM is often used for 24", 26", 700C and 28" rim. 328RPM is often used for 16", 20" and 24" rim."

I think the third letter indicates front or rear motor where "A" means rear, "B" is front", "C" is front also, and "D" is rear again. It seems to follow this pattern.

If there is a "-H" at the very end, it means it is a freewheel hub.

I still can't figure out the first two letters. These must mean something. They do not indicate which motor (Q85, Q100, Q128, etc.) and they do not seem to be consistent in rated power. It would be great if anyone can tell us what first two letters mean.

 

[Nealh]

My 36v AKM128c is;
AKM16052589446
2016 May 25 unit s/n 89446.

BBE3626A;
A indicating 36v as does 36.
It is meant to be 201rpm/15/16mph but actually max's out at 19/20mph in a 700 rim.

 

[Andrew Cooke]

I have a 2017 motor BBC3626A, purchased as a 201rpm 36V motor, this seems to be the ~260rpm I was expecting. This was purchased from BatteryBMS.

I have the speed calibrated as a 28" wheel, and it runs to about 45kph unloaded with a 48V battery fully charged.
When it came to finding P1 I set the speed limiter to 25kph, and played with the numbers until the displayed speed was 25kph unloaded, came out as 175.

I spent some time trying to find out about gearing, and found 2 sets of ratios for sale, the 201rpm 45/33 and the 328rpm 42/33.

Digging through photos on the internet I found a complete set of gears:
motor pinion 12 with a 45
a 33 with 96 on the casing,
this gave a total ratio of 10.91:1, with 16 magnets, 10.91*16 = 174.56, pretty close to 175 so this must be the gears I have.

Since the alternative gears were 42/33 the motor pinion would have to change to mesh, and the 96 on the casing would remain the same. To get things to mesh the motor pinion would have to increase to a 15. This set of gears comes out as a 8.148:1, so I guess P1 would be 130.268, so 131? This is speculation on my part.

I'm not sure if there are any other ratio sets? But there does look to be space on the housing for something bigger than the 45?

Gone off track a bit there, but wanted to be clear as to what my motor is with regards to the code.

 

[pajtaz]

Your number is BBC3626A. Going from my research above, your motor is 36V, 201 rpm, 350W front hub motor. Is it Q75?

As for rest of your post, I have no clue. I just did trial and error per Nealh's posts about setting P1. I found what worked perfectly for me that way and some calculation using ratios I found on various forum posts.

 

[Andrew Cooke]

Your number is BBC3626A. Going from my research above, your motor is 36V, 201 rpm, 350W front hub motor. Is it Q75?

No, it's a Q128C rear motor, supposedly the same as Nealh has in the post above mine, his code was BBE3626A

 

[pajtaz]

Ok then my part number breakdown analysis was wrong.

If you have Q128C like me and Nealh then if you read around various forums, you will find out that the gear ratio could be 13.2:1 for Q128C. Combined with 16 magnets, that would mean your P1 setting should be 212 (13.2 gear ratio x 16 magnets = 212 as per KT-LCD3 user manual). This is the setting I use and it works perfectly. However if your gear ratio is different like in your post above, then who your other numbers for P1 will work. I know for a fact that my setting of 212 is correct for my motor because I tested it with phone GPS speedometer app. Any lower or higher setting is no good.

 

[Nealh]

I was trying out new P1 settings for my AKM128c as 212 no longer worked and my cut speed has reached over 20mph, I have been running it at 48v & 36v with dual KT 25a .
A couple of weeks ago using a 36v battery I had to use P1 of 168 to see a lcd 25km/h cut out but didn't have my GPS to back up the new setting, so need to go out and do this soon when I more able to.
Currently I not being able to ride with much force from my left knee/leg.
I haven't ridden for a proper ride for a couple of weeks as I had a spectacular high side off and bruised/bashed both knees, and they still hurt a little as the bruising is now in full colour.

 

[Andrew Cooke]

I think there are 2 speed systems used in the LCD3, both use the same inputted wheel diameter (in my case I use 28" as I have 700c x 40 tyres). With P2 set to 1 it will use the 1 pulse per rev sensor in the motor, but the speed limiter will still use the motor pulses (there being P1 of them per wheel revolution). With P2 set to 0 the displayed speed will be derived from motor pulses (and show as 0 when coasting).

When you set P1 using GPS you are also correcting for any error in the tyre circumference, so it won't necessarily agree with the gear ratio * magnets number. In a perfect world we'd be able to set the circumference more accurately, but I don't suppose it matters.

I've not done a lot of playing, but I haven't seen any difference in running when P1 is changed. I'm guessing that it's some sort of resonance thing, but maybe it doesn't happen on all controllers? I am using the hall sensors and my drive is sinusoidal. The other possibility is that I'm not hitting the speed limiter, maybe it's linked to either current control, speed limit, or both? If your motor is P1 sensitive, when does this show itself? All the time? Speed limiting? Current limiting?

 

[Nealh]

P1 is sensitive on my bike, the cut off speed certainly is noticeable with changes. I use current control and the speed limiting, I only use 25km/h limit as a base setting. the odo readout is set to mph so I adjust P1 to read 15.5pmh and then see what a gps reads. I adjust P1 there after to fine tune real world actual GPS speed.
I have yet to correlate readout with GPS of late.

KT make so many variations on the controller side you never quite know how they will work with the programming they have.

 

[Andrew Cooke]

P1 should certainly change the speed limit, it's the comments on how smooth the motor runs that are interesting

 

[Nealh]

I went out today with my Garmin GPS and had the P1 set at 168 which I thought was about right previously I have been running with P1 at 212. The lcd was still over reading at 168 so finally settled at 164 which corresponded well with both displays.
The 164/168 corralates with a gearing ratio of 10.5 for my AKM/Q128c.

I have still some more palying/adjusting to a carry out as the cut off is still too high and well above 25kmh with it set within the lcd, the wattage tails off to about 16w at about 16.8mph. Next I will try Andrews 175 to see what occurs then go back and try my original 211/212, I am at the mo erring on the side that the controller or lcd are no longer acting in limiting the speed.