DIY Fix for BBS02/BBSHD Pedal/Throttle Issue

Just to double-check... in the original schematic posted by @fechter "BBS02/BBSHD Pas Correction" there appears two be two transistor symbols. I'm assuming this is just a single KSP13BU as it looks like just one in everyone's actual build photos ;)
 
eBlur said:
Just to double-check... in the original schematic posted by @fechter "BBS02/BBSHD Pas Correction" there appears two be two transistor symbols. I'm assuming this is just a single KSP13BU as it looks like just one in everyone's actual build photos ;)

Correct. That's the symbol for a Darlington.
 
Jackpot! I think I’m good.

Took it apart and confirmed 4.95V at pas connector and blue throttle wire was showing 0.81V idle and 4.05V wide open.

Redid the transistor circuit - this time I used the 2N5308 (different pin configs) and it’s happier.

Getting 4.94V on PAS when idle and as soon as I hit throttle it drops to 0.63V peddling or not.

Going to seal it all up with some RTV. Excited to get my frame back so I can road test this.

Thanks for all the help and patience as I worked it out. Much appreciated!
 
Just an FYI that I had reached out to Luna tech support to see if they had any kind of a firmware fix for this issue. As of Oct 2019 here was their reply:

"Yes they all have this issue. If you’re peddling you can’t use the throttle at the same time.
Essentially if you’re using the throttle you have to stop peddling and vice-versa.
As far as the firmware we’re working on a solution to this but do not have it
fully figured out yet."

@Rassy - you may want to edit the first-post 5/29/19 edit that eludes to a possible-firmware fix, unless you've got any kind of confirmation from someone that has tried and succeeded on firmware that Luna hasn't seen...
 
I can confirm I tried the firmware changes on the page linked and this did not solve the throttle issues for me.

The only solution I have found is by disabling PAS with software settings. And just using throttle as needed.

I have attached a snap of my settings. Note you can play around with PAS settings to adjust max throttle on each level. The most important one I found is.

On basic tab: Make sure assist 0 is limited to 0 current and 0 speed.
On pedal assist tab: change designated assist level from by display to 0.

This relies on the fact that I have no throttle response on PAS0

This has made the BBSHD usable. Would be nice to have PAS. But at least I have smooth throttle and can pedal as needed without jerking around. (also I don't have to pull the motor apart which is a plus)

Hope this helps.
 

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Thanks P913. I think you may have found a nice partial solution to the Pedal/Throttle issue.

In reading your post and looking at your firmware settings I wonder what would happen if instead of setting the Designated Assist Level to 0 in the Pedal Assist section you set it to 0 just in the Throttle Handle section? Then it seems when you ride in PAS level 0 you "might" be able to pedal and/or use the throttle with smooth throttle control. This may not help in the other PAS levels, but as long as you didn't use the throttle you would still have full PAS support, and maybe it would even affect the throttle response in the other PAS levels.

Have you or could you try this and let us know what happens?

Edit: Okay, I see the fallacy in my logic. Please ignore this post! (Well, maybe)
 
Rassy said:
Thanks P913. I think you may have found a nice partial solution to the Pedal/Throttle issue.

In reading your post and looking at your firmware settings I wonder what would happen if instead of setting the Designated Assist Level to 0 in the Pedal Assist section you set it to 0 just in the Throttle Handle section? Then it seems when you ride in PAS level 0 you "might" be able to pedal and/or use the throttle with smooth throttle control. This may not help in the other PAS levels, but as long as you didn't use the throttle you would still have full PAS support, and maybe it would even affect the throttle response in the other PAS levels.

Have you or could you try this and let us know what happens?

Edit: Okay, I see the fallacy in my logic. Please ignore this post! (Well, maybe)

Yeah I did try this. But when you set pedal assist to 0 in throttle section it just kills the throttle completely. It's the same as using my settings then using the screen to switch to PAS0 and notice it disables the throttle. Using the settings I put up you have 0 throttle on PAS0, full throttle on PAS1 and increasing maximum throttle on each of the other PAS settings. Note these may be too low for some. My PAS2 is very week and barely faster than walking the bike when on max throttle.
 
All back together and took it for a quick spin - works flawlessly! Don't know how I rode with the factory behavior, now that I know how it *should* work.

A BIG THANK YOU to the awesome pioneers of this mod!
 
To paraphrase Sir Isaac Newton, "If I have seen further, it is because I have stood on the handlebars of giants." Many thanks to the folks in this thread whose inquisitiveness, intelligence and mechanical ability have brought us closer to a solution.

I have purchased the two types of Darlington transistors and the resistor mentioned in the thread, and may just pick up a Luna controller and commence surgery.

Wish me luck!
 
Thanks for all the foolks to help with that incredible error of bafang.

Two months ago I purchased one controller to replace the controller of my BBSHD that I broke unpotting to make the 50amp mod.
But the new one has the throttle/pas issue.
I make the mod like fletcher says with a KSP13BU transistor and works fine.

Thanks for share your knowledge.
 
All,

I bought a BBS02 in November, finally got the battery pack built and have been commuting on the bike this week. PAS 2 felt most natural to me, but I really just want to be able to throttle to 100% power at any time. Most times, I don't want pedal assist at all.

Flashed the controller tonight after being annoyed with the stock settings (following this thread https://electricbike-blog.com/2015/06/26/a-hackers-guide-to-programming-the-bbs02/), and my PAS 0 throttle settings are acting funky as stated in the Original Post.

Sometimes it will let me pedal while holding the throttle, but if I try to adjust the throttle or go off and back on with the throttle, I have to stop pedaling to get the throttle to activate again.

I'm really hoping there's a software fix, as I don't want to dig into the controller wiring.

May try P913's settings out since I think I can live without the PAS.
 
FlatBlack said:
I'm really hoping there's a software fix, as I don't want to dig into the controller wiring.

May try P913's settings out since I think I can live without the PAS.

It's pretty easy to open the controller side and simply unplug the PAS connector. This will disable PAS completely and you can use the throttle. I rode like this for about a year before coming up with the circuit mod.
 
I am a bit of a loss as I bought a BBSHD in November for my bike and a BBS02 two weeks ago for my wife's bike and both of those work fine I can still run throttle while pedaling in any PAS setting. I do have PAS set for 1 as I did read somewhere that it needed to be a minimum of 1 for both throttle and PAS to work togeather


Edit: I was wrong, my BBSHD is fine but the wife's BBS02 has an issue, if pedaling the throttle only kickin at the half throttle point.... So I guess it is controller mod time.....
 
You may have been lucky and got ones where the firmware is correct. It seems only certain versions of the firmware have this problem.
 
Rassy said:
EDIT 5/29/19: There is finally a possible programming fix for this problem. Here is a link to a thread that you need to read (BOTH PAGES) if you are experiencing this problem: Update on 10/13/19, there is no confirmation that these firmware flashes fix the pedal/throttle issue. I will leave the following link in place, since there is a lot of information there pertaining to firm ware flashes:

https://www.endless-sphere.com/forums/viewtopic.php?f=28&t=100064

EDIT: Fechter has completed and tested a simpler fix for this issue. See his solution five posts down on this page.
So which EDIT is that latest / correct one? I have read the 4 pages of that thread and it doesn't seem to mention anything about it solving throttle issues, nor for BBSHD nor for BBS02. Is it really that there is only a hardware mod fix for this? In that case I'm gonna buy some spare "version A" controllers if I can find any for my BBS02's
 
opperpanter, I have no idea how valid anything is in that link but I think it depends on which firmware you may have in your controller.

I did what you are suggesting, i.e. putting a good spare on the shelf. So currently one trike has an early model BBS02B controller that works properly, the other trike has a later model BBS02B that was repaired as per my first post in this thread, and the one on the shelf is an early model BBS02B that worked properly from the beginning.

Just a note based on your comment above, The BBS02A controller can not be exchanged with a BBS02B controller. Bafang made some small changes to the physical design of the BBS02 shell shortly before they introduced the throttle problem. From my experience no dealers still have the good early BBS02 controllers or even the complete system available.
 
Em3ev still states on their website that they sell units with full throttle on all pas levels (BBS02)

https://em3ev.com/shop/bafang-48v-750w-bbs02-kit/
 
Does "full throttle" mean wide open throttle or full throttle range? I contacted EM3EV after this problem showed up and one of his guys did a test for me that confirmed they had adjusted some of the settings so that the throttle didn't go wide open immediately but it still didn't deliver full range either. This was some time ago, so maybe they have been able to tweak the firmware properly since then. I don't know and don't care to experiment with it at this time.

However if someone were to get a new BBS02 it would be nice to know if Bafang had finally either fixed the firmware or provided a firmware zap to their dealers.
 
Fixed My BBs02b controler! Thank you Fletcher ans Rassy. My older builds worked great with my customized software. Newest build for a didn't work like all my other bikes because of the throttle issue. I tried diffferent changes in software and wasted many hours of my precious weekend daylight hours making changes and test riding. People, don't wate your time. A tedious hareware change saved the day! Mouser part number 512-KSP13BU darlington installed just as Flectchers" simple fix WORKS! the newest BBs02b needs this fix. Now the throttle works perfect as it did before Bafang changed things. Here are some pics of my work. I'm so proud of myself as when I was doing all this all I could think of was that I was gonna blow up the controler but I can not ride this bikewith the changes Bafang made. I ride trails in the mountains and I need the throttle to work correctly or I get jerked all over the place.
 

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Rassy said:
Does "full throttle" mean wide open throttle or full throttle range? I contacted EM3EV after this problem showed up and one of his guys did a test for me that confirmed they had adjusted some of the settings so that the throttle didn't go wide open immediately but it still didn't deliver full range either. This was some time ago, so maybe they have been able to tweak the firmware properly since then. I don't know and don't care to experiment with it at this time.

However if someone were to get a new BBS02 it would be nice to know if Bafang had finally either fixed the firmware or provided a firmware zap to their dealers.
They confirmed their controllers also have the problem.
 
@arcsat, thanks for posting the detail pictures of your fix. Good to hear it worked out for you.

@opperpanter, thanks for the update concerning that the current stock from EM3EV still has the throttle issue. I would not hesitate to purchase one if I was in the market, but would plan to do the hardware fix. The one I fixed is in regular use and has worked properly for over two years now.
 
well I guess I will be a little more broke as I will have to try this on my wife's BBS02, and since it is her's not mine i will order a extra controller from Luna so I can go back to the stock on if I F up...
 
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