BBS01B 36V 250W - trying with higher voltage [success]

[eCue]

Bike rips for a 250w nominal rated curious how many watts is it pushing at full speed and say 3/4 speed ?

 

[RichardMT]

How HVC was disabled: Battery voltage that is seen by the display is damped using TVS diode (ON Semiconductor P6KE15CA TVS-diode DO-15 14.3 V 600 W) to suppress controller’s overvoltage error (HVC). Actual voltage that goes to the motor is not affected, therefore it has more power than it thinks.

=> Hi, I think you'd better change the TVS diode. Please look into Clamping voltage, Working V, Breakdown V.

RichardM.

 

[Maxid]

In my display (850C) there is an option in the settings to switch between battery voltages. Would this already let me use the 36V motor on 14S without the diode?

 

[Rider2000]

Hi Guys,

i want to bring this topic up again.

Like Maxid stated above, some Displays like C961 are flexible in working Volatage (I think up to 60V for C961).

So I really wonder how Wizzeros did it. For me it really sounds strange.

Also in the Controller settings (with programming Software) the rated voltage is stated as 36V.

So, is there any other one did this with success ?

 

[Wizzeros]

Hello again,

Bike rips for a 250w nominal rated curious how many watts is it pushing at full speed and say 3/4 speed ?

I have to look at 3/4 speed, but fully charged at full speed it takes more than 1kW. My coulometer is scaled only to 1kW, but theoretically a new battery like mine could be drained with 1176W. I think at 9/10 or close speed it takes 1kW, then I don't know how fast it rises. The bike stops to accelerate when losses from air drag, tires friction, motor and controller heat dissipation etc. are equal to power consumption from the battery.

How HVC was disabled: Battery voltage that is seen by the display is damped using TVS diode (ON Semiconductor P6KE15CA TVS-diode DO-15 14.3 V 600 W) to suppress controller’s overvoltage error (HVC). Actual voltage that goes to the motor is not affected, therefore it has more power than it thinks.

=> Hi, I think you'd better change the TVS diode. Please look into Clamping voltage, Working V, Breakdown V.

RichardM.

Currently I have two TVS diodes with different damping voltages and they are still working fine. With only one diode I couldn't use all the energy that the battery could provide, because LVC was kicking in. One diode was damping the voltage correctly, but slightly off the perfect limits between controller's HVC and LVC when fully charged and discharged. Therefore, while reaching LVC, I switch between diodes and damp several volts less now, making the read out of the my 850c display the same bit higher and allowing the battery drain completely before LVC is triggered up until the internal BMS of the battery cuts off. I measured cut off voltage and it is ok.

In my display (850C) there is an option in the settings to switch between battery voltages. Would this already let me use the 36V motor on 14S without the diode?

No, sorry, I tried it. At least for BBS01B. That's why I use diodes now. I think that changing setting works for BBS02 and BBSHD though.

Hi Guys,

i want to bring this topic up again.

Like Maxid stated above, some Displays like C961 are flexible in working Volatage (I think up to 60V for C961).

So I really wonder how Wizzeros did it. For me it really sounds strange.

Also in the Controller settings (with programming Software) the rated voltage is stated as 36V.

So, is there any other one did this with success ?

Why does it sound strange? I will try to explain the best I can, however not much to explain here You can also see on some previous picture that my display also survives high voltage, but error is triggered regardless.

 

[marronnier]

Wizzeros

I would like to post my bicycle's specs for everyone looking for such information in the future.

Registered just to thank you for posting your progress and not abandoning the thread! Very useful info for me.
Google is full of "buy a new controller / motor", "use a compatible battery" responses

fechter, thank you for your advice also

 

[Wizzeros]

Hello marronnier,

When I was building that bike I had the same problem finding useful information other than "change battery or controller", so after my mod has finally been working, I decided to contribute by posting full information here. I also felt that it was the least I could do after a huge help from fechter. Without it, I would probably not be able to run my BBS01B on 52V

Thank you fechter!

 

[fechter]

Glad to hear it still works. You were the crash test dummy for that mod.

 

[Frank d]

Hi.

Thanks Wizzeros and Fechter, I have really enjoyed following this amazing upgrade.

I did a controller swop over bbs01b 36v to 48v 750 24amp because I am not as confident as yourself.

I do intend to follow your example on my next kit what are the differences between the methods ?

And if you have any more advice for relatively inexperienced kit builder's on your method it would be appreciated.

Thanks
Frank

 

[Wizzeros]

Glad to hear it still works. You were the crash test dummy for that mod.

It was worth it

I did a controller swop over bbs01b 36v to 48v 750 24amp because I am not as confident as yourself.

I do intend to follow your example on my next kit what are the differences between the methods ?

And if you have any more advice for relatively inexperienced kit builder's on your method it would be appreciated.

I think adding TVS diode is less problematic than changing an entire controller. I got a few questions if there is an easier way than adding a diode. I really don't know what people are afraid of I didn't even open motor's/controller's enclosure. Someone could say I destroyed isolation on the cable from the display. Meh.. This display is the first thing I would change anyway. I cannot read very much from it during sunny days, and it is a bit too bright when it is dark, even after changing to dark background and minimum brightness. When I cover it with my hand, I see the road better. I also have coulometer with green backlight, which is even worse, but it is a different story.

Maybe "TVS diode" sounds very difficult, but in reality it is just this little thing from the photo in the attachment - one little something with two connections. You can even buy a version where polarity does not matter.

I would say the worse part is to choose diodes with correct voltage drop, but they are relatively cheap, so I recommend to buy several to cover quite wide voltage range, and if you find out that the one that you mounted is not enough, then just swap it for another one that you already have on your desk. Or do like I did - add two with a switch between them. Maybe even one with a switch for bypassing would be enough. Anyway, I cannot believe people are not going for this mod! Go for it!

 

[fechter]

I have seen somewhere an extension cable for the display. If you can find one of those, it would be possible to cut the cable and install the TVS diode on the pack voltage line in the cable. Then you could install the cable in line with the existing display connector and have the mod without opening the controller. Easily unmodified too.

 

[Frank d]

That information is very useful.

I will attempt that on my next kit a bbs01b mountain bike installation.

Did the increase in performance surprise you ?
I am amazed at the difference 36v to 48v has made. Uk legal 250w , but the no load speed of 40mph plus. On road 30 plus.

The motor temperature just warm .

Thanks your method seems more cost effective.

 

[kaporal]

I have over voltage protection too and we can programming controller cause I need to return mine in a compagny who repair controller from bafang. The problem is HOW ?

My 52v battery is good but my bbshd is programmed for 48v > error from bafang.

So they tell me to send the controller to reprogram it

 

[fechter]

My 52v battery is good but my bbshd is programmed for 48v > error from bafang.

So they tell me to send the controller to reprogram it

You can get a programming cable and install software on a laptop to program it yourself. If you can fix it by programming, it's better than hacking the hardware. Otherwise the TVS diode approach should solve you problem also.

 

[Cbisbaf]

had the same thing as the post up from me its a thing happening a lot lately my seller just said buy a 48v battery but thats not an option got some spare n4004 here i will give it a shot. sick of draining my battery on a light bulb. thankyou for the post.

 

[Wizzeros]

Did the increase in performance surprise you ?
I am amazed at the difference 36v to 48v has made. Uk legal 250w , but the no load speed of 40mph plus. On road 30 plus.
The motor temperature just warm .

Hi Frank d. Although I didn't ever try with 36V, it did surprise me how good performance it is now with 52V. Yes, it can spin a lot faster compared to 36V, and high voltage allows you to pump more power through the motor with just the same current. However, as it is still not very healthy for my battery to ride 40kph (25mph) constantly, which can take even 15A constant current depending on headwind (and also I think it exceeds motor core saturation point somewhere on the way), I am currently making another ebike project, which hopefully will be more prepared for high constant speeds regardless the weather.

had the same thing as the post up from me its a thing happening a lot lately my seller just said buy a 48v battery but thats not an option got some spare n4004 here i will give it a shot. sick of draining my battery on a light bulb. thankyou for the post.

Draining the battery with a light bulb after every charging is much worse solution than adding a TVS diode. Go for it and let us know how it works!

I also have a question. I am looking for some interesting project of a display with more options than commonly offered ones, like integrated watt meter, "mWh/km" efficiency meter, range calculator, theft protection, legal and unlocked modes, and more. It would be perfect if it was compatible with chain torque sensors, wherever to get them from. I would be grateful if someone could mention any arduino project or so, but if there is nothing like that available, I am thinking of starting my own "arduino" project. I want to implement it to my next bike, but there is a chance that I will implement it also to this one, as it is a really decent commute and cargo bike which can easily keep up with really expensive stock ebikes!

 

[Frank d]

My original bbs01b has been run at 36v for 2,000 miles and now at 48v for 1,000 . The upgrade is a big improvement even at steady speeds.

I have now removed the motor and hope to use an extension cable to the display, as was suggested to install a damper to the LCD.

This motor was used as a winter hack and is now in need of attention, as it is beginning to sound louder and feel rough , not sure what parts usually need replacing on this motor.

I have a couple of 48v batteries that can be used for this mod so should be ok.

Good luck with your new project.

 

[Maxid]

Did we ever figure out what the highest "natural" voltage (when not using a Diode etc.) is so that the HVC error is NOT thrown? I am curious.

Edit: on mine it's 44.4V.

 

[Wizzeros]

Did we ever figure out what the highest "natural" voltage (when not using a Diode etc.) is so that the HVC error is NOT thrown? I am curious.

Edit: on mine it's 44.4V.

This is almost the fully charged voltage for 10s battery (~42V), so it would be reasonable. I didn't check it myself though.

 

[RayGo1]

I just determined that my High Voltage Cutoff is 44.2v with my BBS02 36v 500w system. The battery at 44.2v will trigger the Error Code 7 while 44.1v will run.

So unfortunately for me, my new 36v 15ah lithium-ion battery will not run at full charge unless I try this TVS diode fix or some other option. Charging my li-ion battery from 38.4v to 43.2v added about 5ah capacity. So I basically only have a 5ah battery due to the HVC.

So it seems that the Bafang BBS02 36v 500w mid-drive system was designed to run with lifepo4 batteries.

 

[RayGo1]

Question for Wizzeros or fechter.

I would like to try the TVS diode fix. Do you have any photos of your addition of the diode? I'm concerned about how hot the diode might get and how you isolated/insulated the TVS diode from the remaining wires. Also, how many TVS diodes did you use or any idea how much voltage drop you get per diode? I also like the idea of getting a display extension cable to cut into and leave the existing wiring alone. Thanks.

 

[fechter]

TVS diodes come in a huge assortment of voltages so you can pick what you need. The higher the voltage, the more heat it will dissipate. Diode current will be somewhere around 40mA, so multiply by voltage and you get the heat dissipation. You can use multiple lower voltage diodes in series to spread out the heat.

In my prototype, I stuck the diode to the heat sink in the controller with a blob of silicone glue. With a potted controller this is more work to dig out the potting.

 

[RayGo1]

Thanks for the quick reply.

I would rather use the display extension cable method as you recommended. However, I need help in determining what TVS diode to use. I need to drop my 36v battery's max charge of 50.4v down to my HVC 44.1v. Any suggestions?
Thanks.

 

[fechter]

Thanks for the quick reply.

I would rather use the display extension cable method as you recommended. However, I need help in determining what TVS diode to use. I need to drop my 36v battery's max charge of 50.4v down to my HVC 44.1v. Any suggestions?
Thanks.

Pretty much any of these should work:
https://www.mouser.com/Circuit-Prot...zxl3oZ1z0x4fsZ1z0x43uZ1yzv44wZ1y95zfoZ1z0z819

You want unidirectional with a breakdown voltage of about 7v.

 

[RayGo1]

Thanks for the link.

I ordered several TVS diodes with breakdown voltages of 5v, 6v and 7v to experiment with. Since these are unidirectional diodes, which way should the band on the diode face? Towards or away from the display?

Thanks again for the help. Hope to have results shortly.