Can only set BBSHD to 28amps max?

lupe

10 mW
Joined
Sep 23, 2019
Messages
26
Hi. I just got a BBSHD with 52v 17.5amps. I am trying to find the best settings for the bike/motor. All the advise I have seen says run the BBSHD at 30amps max but for some reason mine seens to be limited to 28amps max. Is this a firmware issue? and what difference is there between 30amps and 28amps max?
 
Only difference is that given similar use, it will last longer.
 
Thanks Tommm- good to know. Any idea why my motor seems to limit amps to 28 - I can't find any mention on this on the interweb anywhere.
 
I think it was a firmware change. For all practical purposes, 28A will be the same as 30A. If I had to guess, I'd say they did that to meet some regulatory requirement going from 48v to 52v.

I really find it to be enough for my bike. To get more, you have to start modifying the shunt.
 
Thanks Fechter!!! I was thinking it must have been firmware - but it is hard to find much info about firmware updates and what they do. Also I am new to all this stuff so forgive me - but what is a/the shunt? Not that I am interested in modifying it :D
 
lupe said:
Thanks Fechter!!! I was thinking it must have been firmware - but it is hard to find much info about firmware updates and what they do. Also I am new to all this stuff so forgive me - but what is a/the shunt? Not that I am interested in modifying it :D

A shunt is a current measuring device, you can trick the controller to outputting more by fooling it by altering the shunt.
In some standalone box contollers, you can modify it with a soldering iron in 2 minutes, the bafang is potted and requires you to replace surface mounted diodes which is a non trivial task itself. Such is the nature of integrated solutions.
 
The shunts are just resistors that are used to measure the current and feed a signal to the processor to engage limiting. By lowering the resistance, the current limit is increased. They are located on the bottom of the controller board, so you have to dig out a lot of potting to remove the board. The stock shunts are a pair of 5 milliohm resistors in parallel. By soldering an additional 5 milliohm resistor on top of the existing ones, you can increase the current limit to around 45A. At this level, things seem to hold together other than the plastic gear which might fail if you run it too hard.

 
Interesting thank you!!!!!! I have another slightly off topic question. I'm going camping in a weeks time. I was thinking about taking my bike battery to charge lights/phones and other USB items. There is no USB port on the battery case (like some I have seen). THe battery has an Anderson connection. Is it possible to connect a USB cable to an anderson connector? I have looked on the internet and there does seem to be a few anderson to USB convertor cables but they all seem to be for 12v or 36v tops.
 
lupe said:
Interesting thank you!!!!!! I have another slightly off topic question. I'm going camping in a weeks time. I was thinking about taking my bike battery to charge lights/phones and other USB items. There is no USB port on the battery case (like some I have seen). THe battery has an Anderson connection. Is it possible to connect a USB cable to an anderson connector? I have looked on the internet and there does seem to be a few anderson to USB convertor cables but they all seem to be for 12v or 36v tops.

You need a buck converter similar to this:
https://www.amazon.com/Prettyia-Waterproof-Voltage-Converter-Inverters/dp/B07PCH9VL4/ref=sr_1_18?keywords=60v+dc+to+usb&qid=1576017013&s=electronics&sr=1-18
 
Most BBSHD units have the USB charge port on the side of the display. Take a look at your display unit.
 
My old BBSHD from avgust 2018 was limited to 25 A in firmware (vendor aliexpress) . I didn't like that limitation :roll: . Now I have 30A and 52V from fasterbikes --> whole new best with 1600+W peak power :mrgreen: :mrgreen: :mrgreen: :bigthumb:
 
Was wondering if anyone knows of an "unlocked" version of the firmware that would permit changing of the max amps, sped etc. From what I understand there is an opensource version of the firmware, I just don't know how likely it is to brick the controller. Was hoping for something fairly stable, tested etc.
 
Dooger67 said:
Was wondering if anyone knows of an "unlocked" version of the firmware that would permit changing of the max amps, sped etc. From what I understand there is an opensource version of the firmware, I just don't know how likely it is to brick the controller. Was hoping for something fairly stable, tested etc.

I'm not aware of anything like that. I have seen some aftermarket controller boards that will fit in the stock space that are completely programmable.
 
I guess 28 amps versus 30 isn't really a big deal. I'm just one of those types that doesn't like to leave any performance on the table. So long as I know there are more tweaks to be had it never stops nagging at me to try to get there. I just have to keep telling myself that the motor and the drive train will last longer if I don't push to Max all the time. :)
 
Dooger67 said:
I guess 28 amps versus 30 isn't really a big deal. I'm just one of those types that doesn't like to leave any performance on the table.

Right, and by the same logic, you'll be leaving reliability and uptime on the table by mucking with the stock controller.

Best performance solution is to keep stock controller intact, while saving up for aftermarket. No downtime, no compromise, and a backup controller is very handy to own.
 
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