bafang bbs02 vs bbshd

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It’s time for a battle of the two best-selling mid-drive e-bike conversion kits from Bafang. In this comparison between the Bafang BBS02 vs BBSHD, we take a closer look at the motors to see if it’s worth forking out the extra money for the BBSHD. The information shared in this article is based on the author’s experience installing both of these Bafang conversion kits over several years.

What’s the Difference Between the BBS02 and BBSHD?

The BBS02 was first released in 2014, and at the time was one of the first plug-and-play mid-drive electric bike kits available. Unfortunately the ‘A’ version suffered from poor quality controller MOSFETs that could not deal with the higher current of the motor, and were very susceptible to overheating leading to a lot of premature failures.

bafang bbs02 750w motor

In 2015 Bafang upgraded the controller from six to nine generic MOSFETs to give it the ability to handle 50% more current, but unfortunately, they still generated a lot of heat.

In 2016 the ‘B’ version was released. This (supposedly) had a better controller with higher quality ‘branded’ IRFB3077 FETs, which convert more of the input watts into power, and less of the input watts into waste heat.

The Bafang BBSHD was introduced in 2016, and the main difference between the two motors is the HD is physically bigger and has external cooling fins (to help with heat dissipation). The Stator is 66% larger, and the controller has twelve IRFB3077 FETs and can handle 30A of continuous current. Input voltage remains the same as for the BBS02.

bafang bbshd motor

What this translates to is the BBSHD will produce more torque, have better heat dissipation (and reliability?) and produce more peak power.

Bafang BBS02 vs BBSHD Power Comparison 

Bafang ModelBatteryPeak Power (Watts)
BBS02 500w 36v36v (42.2v x 25A)1055w
BBS02 500w 48v48v (54.4v x 18A)864w
BBS02 500w 52v52v (58.8v x 18A)1058w
BBS02 750w 48v48v (54.4v x 25A)1200w
BBS02 750w 52v52v (58.8v x 25A)1470w
The voltage figures in brackets are for a fully charged battery. Note: As the voltage drops, so will the power.
Bafang MotorBatteryPeak Power
BBSHD48v (54.4v) x 30A1632w
BBSHD52v (58.8v) x 30A1764w
The voltage figures in brackets are for a fully-charged battery. Note: As the voltage drops, so will the power.

As you can see from the table above there is only 294 watts difference between the BBS02 750w and BBSHD (if a 52v battery is used) – the big difference in the feel of the HD is the amount of torque it produces. This is up to 160N.m against 120N.m for the 750w. The bigger motor spins faster – 130-150 rpm (120 rpm for the 750w) and has a reduction ratio of 1:21.9

Put simply the BBSHD is more robust than the BBS02,  produces more power, but most importantly more torque and much better heat dissipation. Incidentally the ‘HD’ stands for ‘heavy duty’. The HD is also nearly 1kg heavier than the 02, and physically slightly larger.

BBS02 or BBSHD – Which is More Reliable?

I have installed over a hundred Bafang mid-drive motors in the last 5 years. The BBS02B accounts for around 60 units and the BBSHD around 25 units.

I have had long-term reliability issues with both motors, but the BBS02  is more prone to controller failure (I have a box of knackered controllers in my workshop to prove it!)

It seems that there is a correlation between controller failure and battery voltage (plus the way the bike is ridden). I have never had a controller fail on a bike running a 48v battery, but have had over 10 failures on the BBS02 and maybe 3 or 4 on the BBSHD. That is a failure rate of 17% for the 750w and 12% for the HD, which in my opinion is unacceptably high. I know that one of the BBSHD failures was down to a faulty battery BMS, and another was being used daily in very testing conditions.

48v or 52v Battery?

hailong case 48v battery pack

Both controllers have a maximum operating voltage of around 60v. This leaves little margin for error when using a 52v battery. 52v batteries fully charged will produce 58.8v, but I have tested some with a multi-meter and seen over 59v on occasion. A 48v battery will produce 54.4v fresh off the charger – this leaves a reasonable buffer zone.

I prefer a 52v battery. Having the higher start voltage is advantageous as it means the motor will be producing optimum power for longer versus the 48v battery. Another benefit is the same power can be achieved with a slightly lower current, reducing heat build-up.

I covered nearly 2000 miles on a 52v BBS02 powered bike for a year, without even a hint of a problem, but I only used the bike as pedal assist and very rarely went beyond power level 3. I also have a lot of happy customers whose bikes are still running fine after a year, even though a 52v battery was used.

One thing I did start doing on the 750w was limiting the current setting in the firmware to 18 or 20 Amps. After I started doing this controller failure ceased to be a problem. Having the more powerful battery on a BBSHD seems to be less of an issue.

Should I use a Throttle?

The problem I see with the Bafang throttle is that it acts like an on/off switch. There doesn’t seem to be good power modulation. I have altered the firmware settings for the throttle with some success (specifically the start current). But the fact remains, I have no control over how customers use these throttles, and if you are going up a steep hill in full power mode, and you are in the wrong gear, you will be subjecting the motor to unnecessary load – causing rapid heat build-up.

The BBSHD is much less susceptible to the above problem, and can take a lot of abuse (but it still has its limits).

hard tail mountain bike fitted with a bafang bbshd and 52v14ah battery

Which One do I Choose – BBS02 or BBSHD?

This depends on your budget and intended use. If you want an off-road electric bike that you can hammer the hell out of, then I would say go for the BBSHD. The extra £175 price may seem a little excessive, but the HD is just a more robust, more powerful and more efficient motor than its smaller sibling.

If you are going to be doing some mild cross-country-type riding and are not going to be using the throttle or tackling any ridiculously steep climbs then the BBS02 may be more suited to your needs.

As far as battery choice is concerned, I would err on the side of caution and stick with a 48v, but if you do want the benefits of the 52v, then I would limit the max current setting in the firmware to 18-20 Amps, just to be on the safe side.


Both the Bafang BBS02 and BBSHD are amongst the best e-bike conversion kits available. And, they will transform any bike you install them on. But before you part with your hard-earned cash, it is important to remember these motors aren’t perfect and like any electrical item, are prone to problems from time to time.

I always advise customers that you need to be a bit of a DIY enthusiast to run and maintain a Bafang mid-drive. Ultimately, if you treat the motor with a little respect, be very careful with your gear selection (especially when climbing hills or hill starts), and don’t constantly ride in full power mode, then you should be fine.

If you are going to treat your conversion like an off-road electric motorcycle, then it would be worth steering clear of the BBS02 and going for the BBSHD, most suppliers will replace a controller at least once under warranty, but after that, you are on your own. And at over £100 a time, it can become an expensive habit!

Buy the Bafang BBS02B 750w

Buy the Bafang BBSHD

Check the Latest Prices on
Links to the Bafang BBSHD

Thanks for reading. If you have any questions please feel free to leave a comment below.

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    1. Hi,

      There’s a company down in Exeter called custom-built e-bikes who do repairs, or try Electron cycles in Epsom. Where did you get them from? If they were brought from eBay or Amazon and they packed up within a few months of purchase, I’d try and get a refund or warranty replacement. If that doesn’t work and If you paid with PayPal or credit / debit card you might be able to get charge back👍

  1. Hi,

    Thanks for a great article! To adjust the current, do you need a special USB-cable or is it all possible to to via the display? Wonder how much I can do via display and what I need the USB-cable to.


    1. Hi,

      Yes you will need the USB cable and software to adjust the current. It can only be adjusted within the maximum limit (25A BBS02 30A BBSHD). On the display you can usually change maximum speed, number of assist levels and units (metric / imperial). With the USB cable you can alter pedal assist and throttle characteristics, and many other things like low voltage cut-off (for the battery).

      I hope this helps, let me know if you have any more questions.


  2. Hi

    CAn you help please?

    I ordered a tandem recumbent trike for my disabled daughter.

    It should have come with a Schachner MM15 motor and battery, it has arrived with a Bafang BBS01 or 02 motor and generic battery.

    I note a large price differntial between these two motors. Should I be alarmed, happy or indifferent?

    Upon delivery The battery will not charge, it is being changed but it doesn’t give me any confidence in the Bafang unit.

    Am I being overly suspicious



    1. Hi Ken,

      Looking at photos of the Schachner MM15 motor, it looks like a re-branded Tongsheng TSDZ2. I’ve studied the photos and it looks identical to a Tongsheng but with different branding. The Tongsheng motor uses a torque sensing pedal assist which measures pedalling force. The Bafang BBS01/02 uses a cadence sensor which measures pedal rotation. The Bafang is a fairly good motor and comparable to the Tongsheng for reliability. The Bafang generally provides stronger assist (when compared with the Tongsheng). Parts availability is good for both motors and both can be easily serviced or repaired by a competent DIY enthusiast.

      I would ask what cells were used in the battery. If you’ve paid for a battery with premium cells (LG, Samsung etc.) and received a battery with generic cells, then you will have comeback under the trade descriptions act. There should also be a return window under distance selling regulations, where you can return an item within a set timeframe without having to give a reason.

      I hope this helps.


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