Bafang BBS HD PAS fault

[rgvkid]

hi all, i have a strange thing which happens pretty much most journeys on my BBS HD, whereby the PAS level changes by itself. it can go up or down, and it often seems to happen when pulling away using the throttle, though not always. doesn't seem to necessarily happen going over bumps, either.
i had a BBS HD motor originally which also occasionally had the same issue, the first motor is in bits with hall sensors needing replaced, so when i bought a new motor the one thing i didn't replace was the display and button cluster (for power on/off, PAS + and -).
find it hard to believe 2 motors have the same fault, my current motor only has done about 500 miles, so i would suspect maybe a fault with the display/buttons causing this ? but i really don't know enough about it.
any of you helpful folk any ideas at all ?
thanks,
col

 

[guerney]

Are you pressing the UP/DOWN control buttons by accident? Easily done, and this stopped happening to me when I realised that was the cause, in my case.

 

[sjpt]

I've got a similar issue on our 2016 Bosch Motus. I think it is very likely that I often press the keys by mistake (especially with winter gloves on or when manhandling the bike through awkward gates); but it does still seem to happen of its own accord when I don't think I can have pressed the keys. Another possible culprit is the badly designed mounting for the Intuvia display which sometimes cuts out the motor completely.

 

[rgvkid]

hi, thanks for the replies. i thought at first it was me hitting buttons by accident, but deffo majority of the times my hands haven't moved off the grips. i've also physically seen the PAS level change on my display without me pressing any buttons.
the fact that i had same issue (not as bad tho) with my previous motor would suggest to me that either the display or the buttons are maybe at fault ?
the display doesn't show any errors, but it's literally as if you've pressed + or - (sometimes jumps a couple of PAS levels, i have it set to 5).
cheers

 

[guerney]

I wonder if it could it be because of blister buttons failing underneath, like on old TV and HiFi remote controllers? Bafang of course might not use blister buttons, and I'd have to open mine to find out, which I won't do, because that could ruin it's waterproofing...

 

[guerney]

it often seems to happen when pulling away using the throttle

If you're not accidentally hitting buttons while reaching over to engage the throttle, could it be caused by an intermittent wire break? I'd try immobilising the wire, and if that worked, splice in a new piece.

 

[rgvkid]

good suggestions, thank you, will have a look later to see if the button unit can come apart easily. the wire running from it to the screen, i've normally had a cable tie round it, or light mount (tight), so maybe internal wire/s crushed, causing intermittant issue.
so the wire itself is immobile when bike in use, but not to say if a wire issue vibration and knocking isn't causing an issue.
i do feel it has to be button unit or display (surely more likely to be buttons or wiring from them to display) as opposed to anything in the motor, as both identical motors have had same issue.
fyi its dpc18 display and buttons i have

 

[Nealh]

Time to get reliable mid drive like the tsdz2 .

 

[guerney]

Time to get reliable mid drive like the tsdz2 .

Yours seems to be doing great, with all it's cool mods.

 

[Nealh]

It's too soon yet as only have 200 miles on it , albeit 95% towing.
I am quite liking it now I have tinkered with the firmware settings, removing street mode now makes it feel like the Kt's with the extra power if needed.

No matter which version one buys of the 48v TSDZ2 they are all the same, the only differentiating factor is the current set. 250w is set for 12a and the 500w or 750w are set higher as the controller is one and the same.

But for sure the simple 5 - 10 second crank bearing modification is well worth the effort.

 

[guerney]

It's too soon yet as only have 200 miles on it , albeit 95% towing.

3632km so far, and as you know I killed my first controller, and am using my second, which seems to be doing rather well despite brutal towing duties up steep hills in very hot weather, sometimes over 12 miles. I think improvements must have been made since the BBS01. Perhaps I'm speaking too soon... (touch aluminium)