Bafang M625 Preview: A Missed Opportunity?

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Bafang Mid-Drive motor gets a facelift

The Bafang BBS02 mid-drive was first released back in 2014 (BBSHD 2015) and since then it’s undergone several changes to the electrics and internals whilst the exterior has remained largely unchanged. Finally on the 18th of June 2021 the new Bafang M625 was released – but apart from the obvious changes to the exterior has anything changed on the inside?

What’s new with the Bafang M625

At some stage, I’ll be ordering the new Bafang M625 so I can do a full review, but in the meantime, I will go over the spec and what has been changed.

The most obvious change is in the exterior design – both the M625 and M325 have been given a facelift. It’s certainly a pleasant design but nothing particularly ground-breaking. The new exterior boasts larger fins (like the BBSHD) so one would assume that these improve cooling and heat dissipation.

Another big difference is the addition of an auxiliary mounting point on top of the motor. The idea with this is to thread a large steel jubilee clip (supplied with the kit) through the hole and bike downtube to prevent or minimise the dreaded motor movement that has always been a problem on the BBS motors.

I think it’s a bit of a ‘DIY’ solution and having a steel jubilee clip around the downtube doesn’t do much for the aesthetics. They also supply a rubberised adhesive strip to prevent damage to the bike frame paintwork.

Everything else regarding mounting remains the same and you don’t have to use the clamp if you don’t want to. The motor shaft dimensions are as before with a 68mm-73mm version plus there is also a 100mm-120mm version (previously only available on the BBSHD)

Two versions M625 and M325

Looking at the specifications side by side with the BBS02B and BBSHD there doesn’t seem to be a lot of difference apart from the ‘rated voltage’ figure. This has gone up from 48v to 50.4v – whether this means they have made substantial improvements to the controller or not I can’t say for sure at this time.

Battery compatibility

***IMPORTANT – I’ve just contacted a supplier with UK stock and I have been told this new motor will only work with the Bafang battery (50.4v 19Ah) that uses the Samsung 21700 cells. Read the conclusion for my thoughts on this. The specification on the Bafang battery is good – 35A BMS, Samsung 21700 cells and 960Wh, but the battery looks like a brick and weighs 5.5kg!

New Bafang motor specifications

Apart from the change in rated voltage, the rated current has also been reduced – I think this isn’t a bad thing as I always used to re-program the BBS02B to 18A and it still went like a rocket.

The 1000w version has been reduced from 30A (BBSHD) down to 27A and the 750w has been reduced from 25A (BBS02B 750w) down to 20A. The 500w model is now at 13A (the old 48v 500w was 18A). If these reductions to the current improve controller reliability then that’s a good thing.

M625 1000W Motor Specification

Motor model: MM G321.1000.C

Rated power: 1000 W
Rated voltage: 50.4V
Rated efficiency: ≥75%

No-load current: ＜1.6A
Rated current: ＜27A
No-load speed: 126±10RPM

Rated speed: 132±8RPM
Rated torque: ＞75N.m
Maximum torque: ＞160N.m

Axis speed sensing: Speed Sensor
Certification: UL / ROHS / EN14766 /EN14764
Outdoor Temperatures: -20℃~45℃

Relative Humidity: (15-95)%RH
Noise (dB): ≤55

M625 750W Motor Specification

Motor model: MM G321.750.C

Rated power: 750 W
Rated voltage: 50.4V
Rated efficiency: ≥80%

No-load current: ＜1.6A
Rated current: ＜20A
No-load speed: 126±10RPM

Rated speed: 142±8RPM
Rated torque: ＞50N.m
Maximum torque: ＞140N.m

Axis speed sensing: Speed Sensor
Certification: UL / ROHS / EN14766 /EN14764
Outdoor Temperatures: -20℃~45℃

Relative Humidity: (15-95)%RH
Noise (dB): ≤55

M325 500W Motor Specification

Motor model: MM G341.500.C
Rated power: 500 W
Rated voltage: 50.4V

Rated efficiency: ≥78%
No-load current: ＜1.8A
Rated current: ＜13A

No-load speed: 126±10RPM
Rated speed: 116±8RPM
Rated torque: ＞40N.m

Maximum torque: ＞100N.m
Axis speed sensing: Speed Sensor
Certification: UL / ROHS / EN14766 /EN14764

Outdoor Temperatures: ‘-20℃~45℃
Relative Humidity: (15-95)%RH
Noise (dB): ≤55

Buy the Bafang M625 and M325 online (US / EU / UK / AU shipping)

Has the pedal assist changed – did Bafang fit a torque sensor?

I was kind of hoping that Bafang would introduce a torque-sensing version of their DIY e-bike motor but unfortunately, these new models still use the old pedal cadence sensors. I think it’s a missed opportunity and a lot of enthusiasts are going to be disappointed by the lack of torque-sensing pedal assist.

Can you re-program the new Bafang M625?

Bad news I’m afraid – it doesn’t look like the new M625 or M325 can be re-configured. For starters the interface has been changed to a triangular-shaped connector and the communication protocol is different (CAN BUS). Bafang has never been particularly keen on the fact enthusiasts play around with the settings and it looks like they have prevented this in the new model.

New display

It’s nice to see a new display with some increased functionality – there are 5 levels of assistance to choose from and there is added Bluetooth functionality plus a USB charging port (as on the DP-C18).

Accessories

It looks like all the new Bafang M625 and M325 e-bike conversion kits will be shipped out with lights and a toolkit, the throttle looks slightly different and the chainring looks much better than the old version.

Bafang BBSHD vs M625 (1000w)

The picture below is a screenshot and clearly shows a BBS02B and not a BBSHD – I’m a little confused about the weight figure below, surely the new 1000w motor isn’t a whole 1.6kg heavier than the BBSHD? If so I’d love to know where the extra weight comes from. Maybe they’ve completely reworked and beefed up the internals, who knows?

Having a narrow wide chainring is a good idea and I’m sure having all the battery info and Bluetooth connectivity will be a useful addition.

Conclusion

Although Bafang has been constantly making small changes to the BBS motor over the last few years, there’s not been anything major. A lot of DIY e-bike enthusiasts have been waiting in anticipation for an update and I’m not sure if this model goes far enough.

On the surface, it looks very nice, although I can see the new styling not appealing to everyone’s taste. I reckon there have been improvements to the electrics and the firmware, but how this translates to rider experience I won’t know until I get hold of one.

I’m not sure about the auxiliary mounting point on the motor and I’m sure a lot of you will agree it’s a bit of a missed opportunity for something a bit better (more akin to what’s used on the Tongsheng TSDZ2). Having said that it’s better than nothing and you don’t have to use it if you don’t want to.

A hell of a lot of DIY e-bike enthusiasts (including myself) were hoping to see torque-sensing pedal assist on this new model and will be disappointed this hasn’t been the case. Bafang thought the extra cost of implementing it was prohibitive, although I think a lot of buyers would have been happy to pay the extra.

The major caveat for me is the fact you need to purchase the specific 50.4v 19Ah battery – this is going to rule out this motor for a lot of DIY enthusiasts and if this is correct (info came from a supplier) then I think it’s a major negative. The fact that this kit with the specific battery comes in at around £1000 is going to put a lot of potential buyers off.

Another big negative is it doesn’t look like this new model supports re-programming – this will also put a lot of potential buyers off which is a big shame.

Lowering the current across the board seems like a wise move and will only lower the peak power marginally – I always thought the BBS02B and BBSHD had more than enough power anyway.

The DIY e-bike scene has been a massive supporter of Bafang mid-drives for 8 years – I’m assuming they are not replacing the popular BBS02B and BBSHD with these new models. They’re more expensive, and heavier and it appears they can’t be re-programmed and need a specific battery. It’s a big disappointment for me and I don’t think I’ll be spending my money on one of these new kits quite yet until more information emerges.