Q128C Motor

[petr]

d8veh: "As a general rule, the faster the rotor spins, the more the specific power and the higher the efficiency. That's for motors of similar size and construction."

Yes, Dave, that gives sense. Then I just wonder whether the "torque improvement" (or rather better efficiency at low RPM) of the Q100H and Q100C was just a result of a higher gear ratio against the old Q100 series, or if they had to use more expensive magnets at all. I would doubt it. Has anybody proven it?

(As for the Q128C, today I ordered the 42V/328rpm version. I also suppose that it will be internally the same as yours 36V/201rpm. The easiest way to compare these two versions is to measure the winding resistance between two pins using the appropriate method for small resistances (not just a bare multimeter). If the winding is the same and the RPM are the same, then the gear ratio is the same. That may be easier than to disassemble the motor and count the cogs. I will try it when the motor comes, and then report its resistance for comparison.)

Petr

 

[mountainsport]

Only one question left to ask: Where did you buy your Q128, and how much did you pay?

(Oh. and one more last question [strike]You have the Q128C variant. Is that 201 or 328 rpm and is it 36V or 48v?[/strike] Edit: I just realised that this is answered in the first post above. D'oh!)

Thanks, njs.

NJS, hello there is no such thing as a last question on here okay!

MS.

 

[Deleted member 4366]

When they introduced the Q100H, they increased the reduction ratio from 8:1 to 12:1. I think that the 201 rpm and 328 rpm had different windings, so they used the 328 rpm core with the higher reduction ratio to get 260 rpm.

It's actually probably a lot more complicated than that because I know that there's versions with thinner laminations and stronger magnets, but who knows what you get from BMSBattery? They often change things without telling you. My last motors were genuine Aikemas, not the unbranded ones that I always got before.

The main thing is that they're cheap and it's very easy to swap the cores and gears from one hub to another, so you can try different versions.

 

[Spaceystud]

[QUOTE=". It has plenty of torque, but I have a feeling that it would work better in a 26" wheel than 700C.[/QUOTE]

What would be your advice for moderate to steep hills on a 29er?

 

[BornAgainCyclist]

I use this to theoretically work out most efficient speeds, 1:1 ration on the gears and then the cadence tab for speeds at approx 201rpm and 328.

http://www.machars.net/bikecalc.htm

 

[BornAgainCyclist]

Still can't get my head around how 201rpm at 36V equates to 328 at 48V. I make it roughly 268 (purposefully misleading accuracy to keep within the spirit of this conversation) based upon linear Vs

 

[Deleted member 4366]

Still can't get my head around how 201rpm at 36V equates to 328 at 48V. I make it roughly 268 (purposefully misleading accuracy to keep within the spirit of this conversation) based upon linear Vs

Simple. The 201 rpm 36v motor is not 201 rpm. It's 260 rpm!

 

[anotherkiwi]

Simple. The 201 rpm 36v motor is not 201 rpm. It's 260 rpm!

There, that has cleared up the confusion

 

[BornAgainCyclist]

Simple. The 201 rpm 36v motor is not 201 rpm. It's 260 rpm!

Ah. Now thinking I should have gone 48V 201 on my 700 wheel with 35 (37) tyres with the hills I have (10% ish) as I was after the 260ish RPM. Bike is ready for its first test ride this weekend so will let you know how I get on.

 

[BornAgainCyclist]

Just completed the inaugural ride. It is a very easy to ride combination. The BMS battery combination of the 48V battery with controller and the Q128C allow / force me to ride the bike properly, the correct choice of gears etc to get the bike moving with some assistance, the speed and assistance keep on increasing sweetly together up to the limit. The limit is a hard one though, it is a dead stop on the assistance which is very noticeable so some tweaking is to be done. Unloaded unrestricted speed in PAL 5 is indicated at 26 which does make it (my hacking around with the calculator link above) around 320 rpm. It has taken me up the hill I bought it for without any noticeable issue with PAS5 at a good steady legal pace so happy with my choice.

A big thank you to Dave who has helped me out publically and in PM plus all the other people who have posted about their experiences and PM'd me back about my queries. You can have a pic one I've elegantly sorted out the quite a lot of spare wiring.

 

[petr]

d8veh: "...but who knows what you get from BMSBattery?"

My history: One silver Q100H Front had broken clutch springs (repaired), one silver Q100C had thick grease in the ratchet (easy), the last black Q100H Rear (Aikema) works excellent. I like them, here I have found how they look like:

http://www.xtcharger.com/guangzhou-electrony-corporation-achieved-a-complete-success-in-the-27th-china-international-bicycle-fair_n6

Petr