Bafang BBS02 vs BBSHD

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I often get asked this question by customers wanting their bikes converted. Is the Bafang BBSHD worth the extra money or is the BBS02 reliable enough for the job?

At the bottom of this article are links on where to buy the Bafang BBS02 and BBSHD.

What is 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.

***18.6.2021 – Bafang launch the new M625 and M325 mid-drive motor

The Bafang BBSHD was introduced in 2016, and the main differences 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 FET’s 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 table

BafangBatteryPeak Power
BBS02 750w48v (54.4v) x 25A
BBS02 750w52v (58.8v) x 25A 1470w
BBSHD48v (54.4v) x 30A
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

bafang bbshd specification sheet

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.

Which is more reliable – BBS02 or BBSHD?

I have installed over a hundred Bafang mid-drive motors in the last 2-3 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!)

bafang bbshd 1000w electric bike conversion kit
✅Trusted vendor on Aliexpress – EU / UK / US

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 in excess of 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.

Should I use a 48v or 52v battery?

hailong case 48v battery packBoth 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 personally 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.

bafang bbs02b 750w electric bike conversion kit
✅Trusted vendor on Aliexpress – EU / UK / US

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 any issue. See my price comparison table for electric bike batteries.

Should I use a throttle?

The problem I see with the Bafang throttle, is that it acts very much 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 really 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 definitely say go for the BBSHD. The extra £175 on the 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 excellent mid-drive motors 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 motor’s aren’t perfect and like any electrical item, are prone to problems from time to time.

I always advise customers that you really 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

eBay UK
eBay USA
eBay AU
eBay CA
eBay France
eBay Italy
eBay Spain
Amazon (various locales)
Banggood (EU Shipping)

Buy the Bafang BBSHD

eBay UK
eBay USA
eBay AU
eBay CA
eBay DE
eBay FR
eBay Spain
Amazon (UK, EU, US, CA)
Banggood (EU shipping)

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


Passionate E-Bike advocate and enthusiast since 2016. Riding an electric bike helped me to lose weight, get fit and reignite my passion for cycling!

88 thoughts on “Bafang BBS02 vs BBSHD

  • 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



    • 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.


  • Thank you very much for sharing your knowledge. I was intrigued by your comments: “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)” . Would you mind sharing how you have done this as I would like to replicate what you have done. I have the BBSHD with a 52V battery — don’t have big hills and basically want reliability more than anything else — for commuting so that I can get to work without sweating.

    • The settings I usually use on a BBSHD throttle are as follows: Start voltage 11 (1.1v), End voltage 42 (4.2v), Mode: Current, Start current 5, Speed limit: 40km/h, Designated assist is up to you but I usually set it to 9. This is about as smooth as you can get it. If you want to conserve battery power you can cap the peak current off at 18 or 20A (30A as standard). When I used a BBSHD power MTB as a daily ride, I very rarely went about level 2 or 3 unless I was riding off-road. For more info, check out the article on


  • Hi Tony, thanks for the advice you have been offering people you are doing a great job please keep it up.
    I have just purchased a Bafang 750w mid drive kit with a 48v 17amp battery I installed the kit and I can see the bike is going too fast and the motor temperature becoming too hot after 10 miles of flat road non hilly riding so I used the programming cable to reduce the 25 Amps that was set by the manufacturer to 22 Amps and reduced the start current from 50 to 30%, kindly advice if this setting is safe for my controller. Thanks

    • Hi Jim,

      Yes, that is safe. I usually reduce maximum current down to 18A and start current down as low as 5 or 10%. I think Karl on electricbike-blog recommends 15%. Even at 18A the motor will be producing 864w peak power which is plenty, plus it will run a lot cooler. Setting the start current low is also better for controller longevity, although you don’t get that initial surge of power when you start pedalling and the power comes on much smoother.

      Glad you’ve found the blog useful, if you have any more questions, let me know.

      All the best,

      • Thank you for your advice.

        • You’re welcome?

    • Fitted the 48V 750 BBS02 motor to my trek hybrid a couple of months ago with a 48V 17.5Ah battery pack and P850 controller but only as pedal assist with 9 assist levels.
      I was a little hesitant at first spending £750 but what a difference its made to my riding enjoyment. Being 61 with a dodgy knee, uphill sections were hurting but now they are a breeze.
      I haven’t noticed any heat issues but your riding preference appears similar to mine so might take your advice and lower the current settings. I rarely use it above level 5 and mainly on level 1 to give the legs a working and so far battery consumption has been excellent, often doing 40-50 miles with only 20% consumption.
      Anyone humming & harring as to whether to get one, I would definitely say go for it, way cheaper than a dedicated e bike and much easier to get hold of at present. No point abandoning a good bike or selling it off cheap.

      • Hi Paul,

        Thanks for sharing. Glad you’re enjoying the BBS02 – it’s definitely worth lowering the current if you’re not going above 5. You’ll also find you can fine-tune the assist even more.

        All the best,

      • Hallo, ich suche verzweifelt nach einem Mittelmotor mit Rücktritt. Könnt ihr mir da weiter helfen?
        Gibt es so einen von bafang?
        Lg Steffen

  • Hi Tony,

    This is an excellent website, I have really picked up lots of information that will help with my bike build, thank you.

    Can you recommend a supplier in the UK for the BBS02B? I have seen plenty on ebay and amazon but I’m a bit concerned about after sales service with either of those. I also came across custombuilt e bikes who are a little dearer but are in the UK and have good reviews, do you have any experience of them or anyone else? I was hoping to find a link from your website but I couldn’t, although I could have missed it?

    Thanks again,


    • Hi Dan,

      Eclipse Bikes have a good reputation, I’ve brought a few kits off them over the years without any issues. Custom built e-bikes in Exeter are quite a new company but they seem to know their stuff and early reports suggest they offer good after sales service. It might also be worth trying Francis at Electron cycles – he knows Bafang motors inside out and even custom-builds controllers.

      All the best,

  • Hi David

    I have a Trek DS2 2019 and a UK hilly town ride. At age 71 it’s becoming a bit harder and conversion seems to be the way to go but I am having trouble with my due diligence. I can’t find any references to this bike or it’s crank mounting size. Without taking the bike apart and measuring accurately, the best I can come up with is about 90mm. I had been going to go for the Bafang BBS01B 36v 250w with a small (?) 10amp battery ie. pedal assist with the minimum of weight and range. Is the BBSHD my only option or should I be considering a hub drive please?

    • Hi John,

      The 2019 Trek DS2 uses a standard 68mm-73mm threaded bottom bracket so you will be fine with a BBS01B. A 10Ah battery should give you a potential range of 25-35 miles depending on how much assist you use.


      • Are you sure Tony? As mentioned above my BB seems to be a approx. 90mm across. And I have since come across some other info. This website mentions a sealed cartridge

        And another that ‘BB95 (MTB) ………… ): Exclusively used by Trek as an integrated bottom bracket standard, BB90/95-specific bearings press directly into the frame’

        This suggests I might need to do a forlorn search for an adaptor

        • Looking at the photographs and the model / year manufacture I would be very surprised if it’s anything but a 68mm-73mm BB. Most sealed cartridge bearings are 68mm (road / hybrid) 73mm (MTB) or 100mm-120mm (fat bike). Trek specify a sealed cartridge bearing and the type of crankset fitted would indicate a standard threaded BB. Are you taking the measurement across the bottom bracket shell (underside of bike frame). I would advise removing the bottom bracket to be on the safe side – the size will be on the bearing.

  • So they are the same power 48v 30a but the bbshd has better efficiency.

    • The BBS02B is 25A and the BBSHD 30A – the BBSHD controller has more MOSFETS and they’re of higher quality.

  • Hi,

    I have a Van Raam bike that I use with my disabled daughter could someone recommend what Bafang mid crank power I should use? the use is mainly to help me up hills.

    • Hi Lilian,

      I’ve had a look on the Van Raam website and it looks like the Bafang mid-drive might be compatible with some models, but I couldn’t find the bottom bracket specification to be certain. As far as power is concerned, if you were using the bike on UK public cycleways it would need to be the 250w model and speed would have to be limited to 15.5mph. The more powerful variants would be more suited to your needs, but once you go over 250w of continuous power the bike becomes subject to the same laws as a moped. A rear wheel hub motor may also be an option. Let me know what model you have and I’ll do a bit of research.


  • Hi Tony,
    I would like to install a BBSHD on a fat bike Specialized Fat boy 2016. The Bottom Bracket is the PF30 100mm, but cannot find any adaptor PF30 to BSA of 100mm. The link you suggest is up to 92mm if I am not wrong. Any idea where to buy it? Any workaround?

    • Hi Fabio,

      I’ve checked some of my regular suppliers and they only do a 68mm or 73mm PF30 to BSA threaded adaptor. I also had a look on Aliexpress but couldn’t find one there either. I think the best solution would be to purchase a regular sized adaptor like this one and take it to an engineer to see if he can insert a section to widen it to 100mm.


      • Pls. be careful with this solution. You may not be able to fit the motor inside… I took another approach and printed my adapter on a 3d printer. The plastic does a good job, but I had to produce a second version with the inside hole offset to the side from the center to be able to fit the motor inside. Something I didn’t think see at first…

  • I have a 60V battery 20amh and I have a 48V 1000 BBSHD. Can I use this battery for my bafang?

    • No, you wouldn’t be able to use a 60v battery as when fully charged it will exceed the BBSHD’s maximum controller voltage capacity. A 60v battery fully charged is around 67.2v a 48v or 52v battery would be fine. I think Luna Cycle do an uprated controller that can handle up to 72v (for the BBSHD).

  • I need to buy a used bike with mechanical or hydraulic brakes for a bafang kit bbs02. What used bikes would make a good fit with the kit. I am 80 and have 4 replacement joints and ride about 15 mi a day. Maybe I need the had. Thanks for what you do. Duke

    • Hi Duke,

      I’ve converted quite a few Giant Roam hybrid bikes, they’re usually very straightforward. Any decent hybrid should be easy to convert – Trek, Specialized etc. Hybrids are better because they have a more relaxed riding position. Steel touring bikes are also good donors – a Surly Disc Trucker would make an excellent choice – bullet proof frame and suits a Bafang mid-drive perfectly. They usually come fitted with Avid mechanical disc brakes and Shimano XT gearing and wheel hubs.

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


  • I ride mostly city, some gravel, and like to go up hills without working too hard. I have a back dissability, which means i need to use my throttle a lot,, or my back seizes up.

    My ride is a Townie Electra, and I’ve been using a very innadequate bionx. tried my wifes rear hub 500-750 watt bafang, that’s only a bit better. I like torque for going up hills, and don’t want to overheat on a hill that is let’s say 5 blocks constant.

    so, question and concern. On the one hand I have to way out the likelihood of getting stopped by an eager cop who is wattage savvy, apparently they are getting trained a bit on this in Vancouver where I ride. It hasn’t been a point of actually stopping people yet, but it’s in the discussions among the police and their trainers.

    So, here are my thoughts, can a guy likely get away with getting a better motor, that isn’t going to overheat, but you would perhaps want to limit to 500 Watt, and maybe that would satisfy a cop. maybe. if I did do that ‘limit’, then which motor would be best suited, a tuned down bdshd, or a bbs02b? I thought maybe because the bdshd is overbuilt, it will last me longer, not overheat, I’m not trying to save money one over the other, i just want performance, and quality.

    • Hi Kelly,

      I have always found the BBS02B 500w 48v to be plenty powerful enough (plus it’s got 500w stamped on the motor) peak power on this motor is 864 watts and it has enough torque to haul a 110kg male up a 15% gradient with relative ease. I used a BBS02 750w for a year and 2000 miles and never had a problem with overheating – an average ride where I live is 100ft of climbing per mile ridden.

      I also used a BBSHD on a hardtail MTB for a while and it was totally reliable (it’s still running well 3 years later with the new owner). I loved the BBSHD, but very rarely used full power mode, it’s definitely a bit more efficient than the BBS02 especially when used at lower power levels – I used to get 80-90 mile range out of a 48v 17.5Ah battery using the assist wisely.

      The problem is Bafang stamp the power output on their motors so even if you restrict the speed limit and power output at the controller, there’s a chance a cop may confiscate the bike anyway. 250w labels are commonly available in Europe, so you could probably get a 500w one in Canada. I think as long as you ride the bike sensibly and don’t draw attention to yourself, I don’t see any reason why a cop would stop you. I never had any issues here in the UK, but I always kept my speed down, especially in towns.

      If you need any more advice, let me know.


      • Could you put a 2 in front of the 5 and scrub out the last 0?

        • Your best bet would be to use some fine sandpaper, then satin black paint and buy one of the Bafang 250w stickers that are available on eBay or Amazon. Or you could buy the 250w BBS01B and increase the current to 18A using the config software and USB lead.

  • Hi Tony
    I’ve been reading everything I can find before I convert my Scott Aspect and your article is the best by far. I am 73 and think it is time that my bike did most of the work, I have decided on a BBSHD with 48v battery for the best stress free reliable setup, I don’t need to fly so top speed of 20 mph is ok. Some guys use 1 to 1 and do not use the gears, it allows the motor to spin easy, I could fit a 36T front to match my rear and line it up on the cassette. Would you recommend this setup, which display do you think is the most reliable and can speed / load changes be made using the display. Have you any other suggestions, thank you

    • Hi Bryan,

      I used a 36t Lekkie with an 11-36 9-speed on the hybrid I used to own (Bafang BBS02B 750w) and the gears indexed perfectly (with some fine tuning). I’ve struggled to get the BBSHD to work well with a SRAM 1 x 11 set-up, so I think 9-speed is the optimum. You can have up to 9 levels of assist on the C965 / 850c display, but some of the DP-C18 displays only support 5 levels. You can limit the speed through the display (using advanced settings) and you can also change the smoothness of the power start up and electric assist ratios using the USB programming lead and software.

      If you have any more questions, please let me know.


  • Hi Tony, really useful article. I’m a 64 year old woman who loves cycle touring but am finding my ageing body needs more rest than it used to! Thinking of converting my bike – hand built with Woodrup frame and using 32mm Continental tyres – to help me continue long cycling hols. My question is whether the BBS02 or BBSHD with either the 48v or 52v battery would ‘last’ for up to 60 or 70 mile days without a recharge – I’d use it on pedal assist the vast amount of time. Really appreciate your generosity in answering people’s questions. Jos

    • Hi Jos,

      You will be fine if you get the correct battery. I used to regularly get an 80 mile range out of a Bafang BBS02 750w using a 52v battery. That was riding very hilly routes (in Cornwall and Devon) and using mainly low to medium assist at the most. If you were riding flatter routes and relied on the assist less, you could potentially stretch the range to 100 miles.

      The highest quality batteries in the UK are available from Give them a call and ask to speak to Jimmy. I have used his batteries on a lot of conversions and had zero problems.

      If you need any more advice regarding the Bafang, please let me know.

      All the best,

  • Hi Tony!

    I’ve read through a lot of these comments already, and I think I know what you’ll say, but would love your personalized advice just the same! I have a Trek 520, I weigh 180lbs and I will be towing a trailer with an additional 30-40lbs. I don’t care about speed so much. My average ride will be under 15 miles round trip, mostly flat with a few moderate hills. Seems like I should get the BBSHD, but can you recommend a battery that will suit my needs?

    • Hi Jared,

      The BBSHD would definitely be the better option for towing. If you’re only doing 15 mile trips maximum, you should get away with a fairly moderate capacity battery. Something like a 48v 13Ah or 52v 10Ah battery should do the job (as long as it has a 30A BMS). My regular supplier UPP ships batteries from within the US through Amazon and eBay. I’ve purchased over 100 batteries from these guys and have only had a couple of issues, which were sorted without hassle. Here is a link to their 52v10Ah battery on Amazon.


      • Aloha Tony,

        I have learned a ton from your posts…so I thank you for that;)

        I moved to Hawaii last year. In Honolulu there are not very many trails to get use of my mountain bike. So I’m looking to convert my two full suspension mountain bikes into mid drive commuters. I’m in the same boat as the gentleman JARED above. I’ll be towing a trailer with a three-year-old as I look to extend my range with an electric upgrade. I’m between the BBSHD and the TSDZ2. I’m imagining your suggestion will be to go for the BBSHD. Considering where I live it looks like I’m going to have difficulty getting batteries to this location. If you have any suggestions with that I’m all ears. The 48v that I have seen on AliExpress are 12ah. Does that matter? If you take a look at the links below…do you think I would have a problem fitting the battery?

        Thanks in advance for your time!

        • Sorry I didn’t do it prior to posting but I Just mocked up the battery and a Battery Dimension of 365*90*110mm (Length*Width*Height) Wont fit either bike.

          • No worries, it looks like you might have to go the custom-build route, or maybe get a seat post mounted battery. Another option is having a seat post mounted pannier rack (clamp on) with the battery in a bag – I’ve done that before on a full suspension MTB.

        • Hi Nate,

          I’ve had a look at the specs of both bikes and it looks like it could be a tight squeeze getting regular Hailong case batteries in the frames. You need to make a template of 365mm long x 90mm wide x 90mm high, that is the dimensions of the Hailong case (not taking into account the sloping front). Also you will need space in front of the battery in order to remove it from its mounting plate. There is a similar sized side exit battery available, but it is only available in 48v10.5Ah. There’s also a 48v 14Ah available that’s in a compact frame bag – here is a link for that one. The dimensions are 330mm long at the bottom, 350mm long at the top and 130mm high at the rear, 60mm high at the front.

          Regarding motor choice, the BBSHD is definitely going to be the better option (especially for towing little ones). I really like the TSDZ2, but it seems to be better suited to solo, moderate riding / climbing, whereas the Bafang motor just takes all the abuse you can throw at it (and is great for pulling extra weight). I read on a forum somewhere of a guy building a cargo / towing bike with the TSDZ2 and it just wasn’t up to the job.

          If UPP at Aliexpress can’t ship to Hawaii, I would give Luna Cycle a try. It might even be worth seeing if there is anyone in Honolulu who can custom-build lithium battery packs – the cells should be easy enough to get hold of, but you will need to find someone who knows what they’re doing.

          If you have any more questions, let me know.


          • Aloha Tony,

            It looks like the frame bag mount would not work. The side mount MIGHT work. I think I have 5 mm of clearance if I put the nose of the battery towards the bottom bracket. That position should allow full travel of the rear shock. Do you consider that battery acceptable (48v10.5Ah)? I know it’s putting out 25BMS VS the 30 you suggested in an earlier post. Im a newbie so I don’t know if that means I’ll be sacrificing going that route when using a BBSHD. If for some reason the battery doesn’t fit, I’ll throw it on a seat post rack as you suggested. I’ll definitely have to go with the seat post route for my wife’s bike. Which means she’ll have more power than me 🙁

            It turns out you UPP does ship to my location and I’ll use your affiliate link when I place that order. The links you had for motors seem to be on European shipment only. So if there’s someone you like for motors I’m all ears.

            I do see there’s talk about people upgrading the chain ring. Is that something I should do an installation? Not sure if it’s necessary but there’s certainly a lot of talk about it in the blogs.

            Thanks again,

          • Hi Nate,

            My mistake, I didn’t check the BMS rating on the battery. You would definitely need a 30A BMS for the BBSHD – unless you reprogrammed the controller and limited the maximum current to 25A (which would defeat the object). One thing I forgot to ask was the kind of range you’d want from a single charge. Those BBSHD’s really drink the juice when you use them at full power and a 10.5Ah battery wouldn’t give you a lot of range if you were going full power up a long, steep climb.

            Upp only do one other side-exit battery and that too is only rated at 25A, so I would go down the option of a good, sturdy seat post rack – at least that way you can go for something like a 48v 17.5Ah which is going to give you a much better range.

            For the BBSHD, I’ve purchased a few kits from Eunorau before (on Aliexpress) they usually take 14-21 days delivery to the UK, so I would imagine they’d deliver to Hawaii a bit quicker.

            Regarding the chain ring, the one supplied with the BBSHD isn’t the nicest thing to behold, it’s made of steel and tends to get surface rust if exposed to prolonged wet weather. The main issue is 46t is a bit on the large side, especially if you’re climbing lots of hills towing a trailer. Eunorau offer the option of a 42t narrow wide alloy chain ring. I’ve had a few off them and the quality seems okay, but most of my customers go for the Lekkie Bling ring in 36t. This limits your top speed, but gives you much lower gearing for hill climbing – lower gearing is better for motor efficiency. If you want to go for the Lekkie, I think Luna Cycle still sell them.

            I hope this info helps.

            All the best,

  • Hi Tony,

    I have a Trek DS 8.6 and would like to convert it to an eBike. I read there is a Japanese motor (Duru?) that is supposedly of equal quality to Bosch/Yamaha. Do you know anything about these? If not, would you suggest a Bafang for this job. Also, where are you located?

    • Hi Ken,

      I have Googled Duru ebike motor and didn’t come up with anything. There is an interesting new kit available soon from Italian company Bikee Bike. It is a mid-drive kit (road legal) that only weighs 1.5kg for the motor and a total of 4kg including a 250 watt hour battery. It costs 499 Euros and looks like s great little kit, they have designed it so there is no drag when the motor is not in use. Here is a link to their website.

      I am based in Cornwall, UK not far from Plymouth.


  • Hi Tony my wife & I both have Specialized hybrid bikes (5yrs old)
    and i would be interested in costs to convert BBS02 750W – can you give me a budget cost for you doing the work. Also what part of the country are you in for me to deliver. The articles are very informative

    • Hi Nigel,

      I have sent you an email with my phone number. Thank you for your positive feedback on my articles.


  • Hi guys.
    I am a motorbike and bike mechanic guy. But at moment i work with rickshaw as city guide. I ride with my bafang bbshd 1000w everyday to work back and fort 30km. And as city guide on my rickshaw now i have the bafang bbs02 750w motor . I can say that booth bafang motors are nice bbshd is robust and powerfull ok if you use allways max level your 52v 18AH battery can reach 25 km distance… Soo not a problem. But what i want to say is i used the one year tongsheng 750w on my rickshaw that one i dont recomend any one. I change the blue gear 3 times allso the metwl gear even sucks more becouse of bad mayerial. At last the motor was totaly defekt after 6 months use. It mades me allways problems. Dont buy tongsheng its worse. Bafang is good.

  • Hey Tony, I have a couple points I was hoping to receive clarification on.

    Due to budgetary reasons, a new BBSHD kit shipped to Canada would be a bit much to handle. However, I have the opportunity to purchase a used BBS02B 750w with 42t Lekkie chaining and two 48v 13.6ah batteries for an affordable cost. I think this may be appropriate for me since I’ve previously ridden a friend’s Shimano Steps E6000 250w powered ebike with only 60 n.m. of torque for extended periods of single track including fairly steep climbs and found the power delivery to be satisfactory. I’m a mid 20s male in good shape sub 200lbs and am really only looking for mild assist 90% of the time. I doubt I will require anywhere near the peak 1200-1360w reportedly melting the BBS02 controllers and nylon gear for long periods of time, and my main concern is reliability over power with this unit. With my use case out of the way, my questions are this:
    1. What wattage in your experience can the BBS02 manage for extended periods (assuming good peddling cadence)? I understand that 25a 48v full PAS isn’t doable, but have you experienced heat soak on PAS level 3-6/9? What about on 18a 48v limited units at full PAS? Not super clear where the line is, I’ve never heard of a 36v 500w BBS02 having heat or reliability issues for example.
    2. Is the BBS02B 3077 controller and nylon primary reduction gear reliable with 25a and a 48v battery when heat is kept to a minimum? I will be installing a temp probe and am not going to be using peak PAS or throttle for long. However, for short steep climbs and general foolery such as wheelies (in granny gear and high cadence ofc) is there still a significant risk of blowing a controller?

    Thanks a ton, appreciate the time to read and reply.

    • Hi John,

      I used a BBS02B 750w for a year, and covered about 2000 miles in that time, without any issues. I was running a 52v20ah LG cell battery pack.

      I reprogrammed the controller using Karl’s special Sauce but reduced the maximum current to 18A. I used it mainly in PAS 1-3, very rarely needed to use anything above that as I was using to bike to improve my fitness.

      I would say 250w-500w is the sweet spot for continuous power, mine never got hot, even after a long steep climb. You should be fine using the throttle, but always set the start current to around 10%, it is set at 20% out of the factory, which I think is too high. All the failures that I’ve encountered were using 52v batteries and were putting out the full 25A, so by reprogramming you should greatly reduce the chance of blowing the controller.

      If you need any more info, let me know.


  • l’m oriented to the purchase of a Bafang Mid DriveBBS02B 36 Volt-500 Watt motor, but before proceeding I would like to have, if possible, a technical clarification and more precisely:
    1) The above engine, from the manufacturer’s website Bafang, is equipped with a 36Volt-25Ampere controller.
    I ask you to know if the aforementioned motor is electromechanically constructive (except the Controller) to the Model 88S02B 48 Volt-750 Watt.
    My question is motivateci by the situation of already owning a 36 Volt battery; more clearly I would like to buy the 36 Volt-500 Watt motor and in the future have the possibility to replace the 36 Volt- 25 Ampere Controller with the 48 Volt-25 Ampere Controller to be able to use the full power as that of the 48 Volt-750 Watt Motor.
    lt is obvious that in this situation I would also replace the 36 Volt battery with a 48 o 52 Volt battery.
    Thanks and cordiality

    • Hi Vittorio,

      Yes, you can upgrade from a 36v to 48v controller on the BBS02B as long as the replacement 48v controller is for the ‘B’ model specifically.

      As far as I am aware, the motor internals are the same as the BBS02B 750w.

      All the best,

      • Good Morning
        I am very grateful for the prompt reply that gives me the opportunity to make my purchase idea really flexible.
        I am happy for the possibility of being able, in the future, to modify and increase the power of the Engine.
        For your information, some shops (Greenergy Electric Bike Store, pswpower Store, Greenergy Electric Bike Store) have responded negatively to the same request.
        Maybe they have unclear interests.
        I found your site organized in an excellent and very clear and comprehensive way in dealing with the topics.
        Thanks and cordiality

        • Hi Vittorio,

          Thank you for your positive comments, much appreciated. If you need any more help or advice, please let me know.

          Kind regards,

  • Hi,
    Question should the motor fit on a octalink 68mm?
    Since I live in Swiss Jura and I need the bike to pull my children chariot to school I probably need a 36 T ?
    I have actually a rear motor bafang 250w on my e MTB and the power out of it is not enough to pull I have I think just 45 nm torque do you think it will work with the Bas02 motor?
    Any suggestions (since I am driving on Street I can’t take the BBSHD)
    Thanks in advance

    • Hi Filip,

      If your bike has an Octalink bottom bracket, then the Bafang BBS02 will fit no problem. I have fitted quite a few BBS02 motors to bikes with this kind of Bottom Bracket.


      • Thanks a lot Tony for my last answer,
        One more question, I may have a solution to make the Bafang bbshd legal in Swiss for street (with internal programing) it is a grey zone area here but the country is quiet liberal…
        Anyway my question is which motor wilI fit best I have a cruiser for 2 kids chariot with 2 kids in it 45 kg all in. I have in jura up to 20% street and even more in my own street .And I sometimes need to climb 500m in the forest with the kids(I am leaving at 900m and the town is at 450 m above see)
        Could the bb02 750w manage it or I need to have the big one bbshd?and do you think that I could put the battery on a special luggage compartment? I have a hardtrail small triangle frame and I think just the Halong 2 battery will fit…and they have just 10,8 Ah I think because other battery will be hard to remove upward.
        Maybe you have any suggestions?
        By the way your internet forum and topics is great,faboulus even.
        I forwarded it to a lot of friends.
        Thanks for your answer

        • Hi Filip,

          Thank you for your positive comments, they are much appreciated.

          In answer to your question, I would personally say the BBSHD would be much better suited to your needs. I have installed lots of BBS02’s and BBSHD’s over the last 3 years and the BBSHD is just a more robust motor, plus it produces greater torque and the controller is more reliable under load than the BBS02 controller.

          Where I live in Cornwall, I have several 15% – 25% climbs within 2km of my house, and when I have used the BBSHD, it barely gets warm, whereas the BBS02 can get quite hot after a sustained steep climb.

          Regarding the battery. The Hailong 2 case (the larger version with the USB) is available up to 52v17.5ah. But there are other style cases available which remove sideways. This might be more suitable for your particular frame.

          All the best,

  • Thanks a lot Tony. Everything has been ordered yesterday. Next step is gonna the “Montage”.
    Many thanks for sharing your experience with this community.


    • Thank you Philippe, Glad to have been of assistance.


  • Thanks a lot Tony.

    I already ordered the BBSHD with a 42t (was proposed on the Ali-Express web site).
    I also ordered the bsbf-1 Stabilizer bar to avoid motor rotation because of the torque.
    I have one more question if I may : I read a lot on the battery charge and Luna-Cycle are really recommending the charger that can limit the battery charge to 80 or 90% which is going to contribute heavily to the Battery Life duration (almost doubles it according to this guy :
    Taking the price of a new battery in consideration, this may be worse a buy.

    Thanks again.
    Warm regards,

    • Hi Philippe,

      The stabilizer bar is always a good idea, I fit them quite a lot nowadays, as it’s far easier than having to tighten up the lockring every couple of hundred kilometres.

      Regarding charging your battery to 80-90% – this can be beneficial if done on occasion, particularly if you are not using the bike for a few days or more. It is never a good idea to fully charge a battery and then not ride the bike for a while. On the other hand, if you only charged the battery to say 80% for most of the time, you may cause the cells to become unbalanced and this would have a detrimental effect on the performance and longevity.

      I have an acquaintance who is an expert on lithium battery technology and the increase in longevity that is possible from partially charging from time to time is minimal over a five year period (this guy has made lithium batteries for Cambridge University EV projects). So i’m a little sceptical of the claim it can double the life of the battery.

      The other thing to consider is the way lithium battery technology is progressing, in another 5 years we should see big reductions in the size and weight of ebike batteries, due to increased cell energy density.

      Having said all of the above, the Luna charger is a very good quality and reliable charger, you can monitor battery voltage and alter the charge current. Which is useful.

      All the best,

  • Hi Tony,

    Thanks for your great article. Very useful to understand the pro and the con of both engines. I am planning exactely the same configuration as your last picture: I am buying a brand new decathlon B-Twin ST540 and a and I’ll order a BBSHD from the site you recommand with a 52v 17.5 AH battery. I already noted your recommendation to limit the input current to 20A. Any advice, recommendation, warning building this e-bike? Was the Chain line a problem and did you buy a special Chain ring to align it? Thanks a lot for your help. Have a great day.

    • Hi Philippe,

      Glad you found my article helpful.

      There are a couple of things I would recommend when fitting this motor to the ST540: The standard 46t chainring that comes with the BBSHD is, in my opinion too large. You can fit it but you may need a spacer as it can make contact with the chainstay. I usually fit a smaller 36t or 42t Alloy chainring from the French company PreciAlps who specialise in Bafang parts and make their own high quality CNC machined chainrings especially for the BBSHD.

      It may also be worth purchasing a Bafang motor spacer (just in case), as due to the angle of the chainstay.

      It isn’t absolutely necessary to limit the current to 20A on the BBSHD, as the motor is quite robust and can handle the 30A maximum current very well. You will get better battery range though, if you do choose to limit the current.

      If you need any more advice, please let me know.

      All the best,

  • Hi Tony

    Thanks for the great review!

    You stated that the motor has a reduction ratio of 1:21.9. That is a massive reduction! Wouldn’t that mean a cadence of 100 rpm could cause the motor to spin at 2190 rpm?

    Did you mean 1:2.19 ?

    • Hi Shen,

      Thank you for your positive comment.

      In answer to your question, you are correct about the 1:21.9 reduction ratio. This figure is listed by practically every single Bafang supplier.

      Apparently the correct ratio is 21.9:1 with a 2 stage gear reduction using pinions and gears – it took a bit of searching but I found the correct figure on the EBR forum.

      I hope this answers your question.

      All the best,

    • P.s.I forget inform you that in swiss I can drive an e bike up to 500w without any problem above it I need to register.
      But I did not see any control so maybe the heavy duty with 25 kmh max speed will work?
      Anyone knows if the BS 03 can be limited to 500w with the programing tools?
      Thanks for the help

      • There is a 36v 500w version of the BBS02 available – this has ‘500w’ stamped on the underside of the motor.

        The BBSHD can be limited by reducing the maximum current in the pedal assist menu (using the Bafang configuration tool). You can also limit the power (and speed) in the pedal assist settings using the ‘limit current’ and ‘limit speed’ settings. You would need to reduce the maximum current (A) down from 30A to 11A.

        The speed can also be limited on the display.

        If you need any more advice, please let me know.

  • i read your comment and i am thinking of buying a mid drive motor , about a 1000w to climb a 600m hill very steep 9km . i want to use it in p.a.s mood . so i will still get a work out what brand should i buy and model . thanks .

    • I personally think you would be better off with the BBSHD, simply because it is a more robust motor and runs cooler than the BBS02. I recently converted a customer’s bike using a BBSHD and I reprogrammed the controller to limit the maximum current from 30A to 20A and I changed the PAS settings to make pedal assist really smooth and progressive.

      I also really like the Tongsheng TSDZ2, which is available in 52v 750w version. This motor uses a torque-sensing pedal assist similar to the Bosch motor, but I’m not overly confident with its ability to handle sustained load especially on a 600m climb over 9km.

      Out of all of the motors I have installed I’m a big fan of the BBSHD, it’s smooth, quiet and can handle sustained long hill climbs with ease (and gets barely warm in the process).

      If you need any more information, please let me know.

      All the best,

      • Hello Tony,
        can you send screenshot of PASS settings for BBSHD to make pedal assist really smooth and progressive?

        Best regards


        • Hi Vedran,

          If you visit this blog post by Karl Gesslein, and use the settings for ‘Karls special sauce’ – you will get very smooth and progressive pedal assist.

          The screenshots are from a BBS02 750w, but I have tested these settings on several BBSHD’s and they work the same. What the settings do is lower the start current, and also smooth out the way the power ramps up when pedalling starts. It makes the motor a lot smoother to ride.

          I hope this helps,if you need any more advice, let me know.

          All the best,

  • Interesting article and useful too! Thinking of putting one on a recumbent bamboo trike i’m building for loads and long distances (round europe for starters –
    I thought we were only allowed 250w here in europe tho – is that gonna be a problem? or don’t they check

    Many Thanks pSi

    • Hi,

      Thank you for your positive comments.

      If you are planning on doing lots of mileage in Europe, I would recommend staying the right side of the law by using a Bafang BBS01B 250w or Tongsheng TSDZ2 250w.

      A lot of people in the UK and Europe choose to ride higher powered e-bikes. Generally the police won’t give an electric bike a second glance as long as the bike is being ridden responsibly and not too fast, but if an accident did occur there would be serious legal ramifications if you were riding a higher powered e-bike.

      All the best,

  • Thanks Tony for taking the time to document and share your knowledge, that info sealed it for me. I am building my 4th off-road bike using HD, was tempted to use the 02 to save a bit of weight and give better BB clearance. Current bike is mostly drawing 200-600 Watts, except when I hit throttle for sand or gnarly hill climb (throttle is set to max Assist level). I put an 02 on a small mtb for my wife, and while it felt a bit lame I had thought I could live with it on my off-road machine. However, reading your article, I realise I would be using it too close to its design limit, for too long, it would end in tears!

    • Hi John,

      Glad you found the information useful. Your feedback is much appreciated.

      The BBSHD is definitely worth the extra money if your going to be putting any bike through its paces. In my experience the BBS02 is fine for mild xc riding, but anything more and that’s where the problems start. Out of all the mid-drives I’ve installed in the last three years the HD wins it hands down for the sheer abuse the motor will take – that’s why it has always been popular with customers in North Wales and the Scottish highlands!

      All the best,

  • Great info, thanks. My use is going to include mostly paved roads on a fairly heavy cargo bike loaded with groceries and a 40+ lb kid in a trailer. Occasional use will include some bike camping with a loaded bike and trailer using dirt roads with but not very steep say <10% gradients. Would you recommend the HD motor with 48v or 52v battery? Is it a reasonable strategy to limit the 52v in order to get a longer use time between charging?


    • Hi Chris,
      Yes, I would definitely recommend the BBSHD with a 52v battery for a cargo bike. To maximise battery range, I would limit the assisted speed to no more than 20 mph and only use the higher power levels when you really need to. I used to get 80-90 mile range out of a BBSHD powered mountain bike with a 52v 21ah triangle battery.

      If you have any more questions, please let me know.


  • Very informative and well written review. Thanks, keep up the good work. Den

    • Hi Den,

      Thanks for the positive feedback, glad you enjoyed the review.

  • Very helpful for riders to choose which is best system combination,great!

    • Thank you for your positive comment Jayson.
      All the best,

  • Great article! Very useful info

    • Thanks for your positive comments, much appreciated.

    • Hi Tony.

      Great website and thanks for the time you have put into helping us all out with this real world information.

      I have been looking at making my 2008 specialised sirrus elite my commuter bike for work which would be 16 mile round trip which is all on the road which is flat.
      I would be looking at wanting to cruise at between 20 and 25 mph with the ability to get a little bit more.
      I am a 75 kilo 30s bloke that is happy to pedal hard also.

      Was thinking is the hd on a 48v system just to be safe on the drivetrain would be a good buy for this or overkill?

      Regards David.

      • Hi David,

        Glad you like the website, good feedback is always appreciated.

        In answer to your question, usually I would say the 36v 500w or 48v 750w BBS02B would be adequate, but for maintaining a higher speed over a longer distance you might be better off with the HD. I say this from a reliability perspective, as the HD can handle more power for longer periods without getting too hot. The HD is also more efficient when used at lower power levels.

        I reckon you could probably run it at 50% power and still comfortably maintain 20-25mph without breaking into a sweat.

        I’ve converted a Specialized Sirrus before and it was nice and straightforward. I would recommend fitting a gearshift sensor to save wearing out the drivetrain and smoothing out the gear changes.

        If you need any more advice, let me know.


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