Bafang has finally decided that their P75NF75 mosfets on the 750 Watt BBS02 are grossly inadequate for the 1200 Watts that they allow to flow through the controller when it is cranked on. It sounds like they are now using the IRFB3077 mosfets which should run much cooler and be able to handle more amps for longer without popping like jiffypop over a bonfire.
Under all that horrible-to-remove potting material lies newer cooler running mosfets with the latest BBS02 750W units.
What does this mean to you the consumer? It means you can beat on that new BBS02 even harder than you have been beating on your old BBS02 unit without fear of controller failure. That doesn’t mean that your windings won’t melt, the nylon gear won’t peanut butter and the axle won’t bend when you hit big drops, or your drive unit will fail in many other nasty ways. It does mean that the newer controllers should be less likely to fail.
Paul from em3ev just posted this on his website last week.
Since June we have been supplying all of our 750W BBS02 kits (controllers too) with an upgraded version of the standard controller. We have been supplying IRFB3077 mosfets to Bafang for fitment into our kits. Bafang almost immediately realised that what I’ve been telling them for over a year was true and they decided to use the same mosfets in future production (at least for the 750W BBS02, not sure about other models). Early signs are that this has improved the reliability of the 750W BBS02 Controller which has always been the weakest point of the 750W BBS02. Our version of the upgraded controller has a model number ending 206.1, whereas the previous version with lower specification mosfets had a number ending 206 (this numbering system applies to our kits, not sure how it applies to kits sourced elsewhere). To celebrate this improved product, we are making it easier to option the kit exactly as you want and with a little discount too
How do you know if your 750W BBS02 has the newer mosfets? If you bought it from em3ev and your model number ends in 206.1 or later than you are set. If you bought it from somewhere else then you might have the good mosfets or you might have the bad ones. It will be nearly impossible to tell without a whole lot of work. It does seem that any new BBS02 750W drive units ordered from this point forward from reputable vendors will have the newer mosfets. If your controller blows you can always just replace your mosfets yourself but be aware it is a royal PITA.
Lectric Cycles has also now started listing the BBS02 100mm drive units shipped with the newer mosfets as a different webpage from their normal 100mm kits listed here. The price is the same, $1200 for the 750W drive unit.
A huge thank you to Paul for advocating to Bafang on behalf of the disgruntled consumer and helping to produce an even better product to help compete with the grossly under-powered Bosch drive unit.
Did I mention how much I hate the Bosch drive unit?
Ride On.
ElectricBike-Blog.com 
I asked Eric at Lunacycle if the BBS02s he was selling had the updated MOSFETs .He replied that he assumed they did.He got back to me a couple of days later and said that the first shipment did not but that later shipments arriving September 9th and later would have them. Cudos to him for taking the effort to look into it and getting back to me.
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Good to know. Honesty in vendors is always a good thing.
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Just checked the email Eric sent me and the upgraded BBS02s will arrive sometime in September rather than after September 9th. My bad.
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Hi,
Could you tell me why it’s better ?
When I compare the specs, I only see a better Rds but a worser (twice) input capacitor and it’s really important, the mosfet is much more heating during the switching time than the full passing.
If they didn’t change the mosfet driver, it’s a little useless.
Thank you.
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Was awaiting a response about the input capacitor.
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I am seeing specs for the BBs02 – controller upgrade having 12 MOSFETs. It this correct?
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Yes that is confirmed.
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Hola Karl,
Soy un seguidor de tu sabiduria, que me impresiona tu conocimiento de la unidad BB02 y siguiendo tus pasos me decidi a cambiar los MOSFET por CSD19536KCS pero cual es mi sorpresa que los conecto al motor y me da fallo de comunicacion, error 30. he comprovado las conexiones y las soldaduras y esta todo correcto no hay cortocircuitos ni derivaciones, me echas un cable?. Si tienes un minuto te agradeceria tu valioso tiempo, si no puedes pues nada seguire haciendo pruebas y leyendo tus intervenciones llenas de esperiencia. Un cordial saludo Pedro
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Creo que lo mejor es comprar sólo un controlador con MOSFETs actualizados de Pablo en em3ev o Eric Lunacycles. Siento que su actualización MOSFET no funcionaba. Lo más probable si las conexiones de los cables son buenas hay algo dañado en la placa de circuito. Buena suerte.
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Hi what are the good mosfets to buy for the BBSHD controller? or are they all the same? I am getting bored of buying new controllers when i can just replace these cheep mosfet, ty for any help.
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Hello
Could someone help me with my problem with the pedal assist?
It doesn’t work correctly and its stops working after a few seconds. You can check the video in the links below
Dropbox: https://www.dropbox.com/s/6gyo5tfb6m0uysz/BafangvideoAllin1smallsize.mp4?dl=0
MediaFire: https://www.mediafire.com/file/9owkng6ghpqpn7w/BafangvideoAllin1smallsize.mp4/file
GoogleDrive: https://drive.google.com/drive/folders/1gqvb_eDRITrOKZJxmWF5GKFAhUGFl8xP?usp=sharing
one extra video GoogleDrive: https://drive.google.com/file/d/14dPRp7cNPxrz1yxDhNpF7BdkexE2Wre9/view?usp=sharing
1300 kilometers was working perfect, And when I changed yesterday the Keep Current % from 100 to 60, it “broke” as you can see on the videos.
You can see my bafang settings on the last “extra” video.
I have read all the articles on this website before i even buy the bafang, and programmed my motor from day 1, I lowered the amps to 18 and never had my battery been lower than 40Volts
BBS02 model 2019, firmware Ver V2.0.1.1 Hardware V1.1, Battery 48V 17,5ah LG.
Any advice would be great, I can’t really find any solution by communicating with the Chinese people on AliExpress, (even if the seller is one of the TOP on selling bafang and with tones of 5stars reviews)
Regards!
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Did you try changing it back to 100%?
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Yes, no matter what settings i use it not getting fixed… Should i reprogram using STC? if yes which file do i use for .bin and what MCU? i cant find details online for bbs02
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Also, controller wont cut off power when shifting, (shift sensor blinks normally)
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Today I tried new display and new battery but the problem is still there. Something new: after using my friends’ new battery the display indicates low battery voltage (red) but it was 51.2V! When I went back to my own battery the display kept showing low battery voltage (red empty battery) with 53V! O used the usb once again just to mess around with the settings, and for no reason (just because i flashed some random settings the batter low voltage indicator stopped coming up. But the issue is thill here. Also, on Walking mode (most of the times (randomly) the well is spinning like crazy fast (probably Full speed) …. Any idea?
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These MOSFETs are way back ordered. I can get the IRF1407PBF to replace them in my controller. 80v 130A. any comments (my controller is not buried in potting material)
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Where can I buy mostfets? The ones I need to replace is marked: “IRFB3077 IΩR P821D M6XW” and “IRFB3077 IΩR P734D FRPH”
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Digikey?
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