bafang suddenly cut out today

[it is i footpump]

hello all this refers to my bbso1 build in thread below.
today went for a ride on a faily busy road, pas 6 battery about 70% went onto a cycle path and the moter /display cut out.
display was not lit.
turned battery on/off display lit up, tried bike and it cut out again using pas.
as i was at the start of a steepish hill. i went onto the pavement and used the throttle which worked ok.
tried pas this now seemed to function rode the remaining mile and a half home.

so am a bit baffled on why it suddenly cut out ,i have done about 250 miles since installing the kit

any ideas on what to check
thanks all

 

[saneagle]

Did it go up the hill OK with the throttle? Are you absolutely sure that the throttle works properly all the time?

If it did, the problem can only be with the PAS. there's a connector and wire inside the controller compartment. If there's npthing wrong with that, you'll have to strip the motor to look at the PAS itself. I have seen them break up before, but I don't know the cause or how frequently that happens.

 

[guerney]

IIRC - Wasn't there a similar issue with a BBS01 a few weeks ago? Magnet was too far away from the speed sensor.

 

[Nealh]

Magnet gap is critical and can cause cut outs.
Better still buy a nice reliable TSDZ2/8 , I have had more reliability from mine then a BBS.

 

[it is i footpump]

hi all couple of short rides today ,first 2 miles ok,
second it cut out about 4 times , i do not think its magnat gap as the display would still be lit.
when it cuts out display is black, i have to turn battery off then on again ,display lights up then select pas level, ride again then it cuts out.
battery has had very little use prior to bike build.

if controller was faulty would i not get some kind of error code on display?

nealh i have a original tdz2. the only time i rode it home in heavy rain 3 miles, some days later the moter was making a rather graunchy sound, sent the moter to woosh to replace some bearings,

 

[matthewslack]

I suspect there may be a not good enough contact(s) in your wiring somewhere, and quite likely between battery and battery mount.

It always seems to restart, and run for miles not just metres, so does not sound like a fundamentally broken component.

I have had similar issues from time to time with my remotely mounted battery, always resolved by increasing the tightness holding contact block to battery.

If it is the common long flat prongs in the battery mount, try a tiny twist or sideways bend to force more contact pressure, and strap the battery plus mount down really tight.

 

[AGS]

On mine the display will time out if it doesn’t see a wheel speed signal after 5 minutes.

The time out is adjustable on the display.

I use 2 magnets for the speed sensor to increase the magnetic field.

 

[guerney]

Might have been some other kit I was thinking of, might even have been on ES, I'm probably recalling incorrectly - can't find the thread. On the BBS01B: if the PAS is activated but thre's no speed detection via speed sensor, an error is shown on my DPC18 display. If neither PAS or speed is detected, the display automatically shuts off after 3 minutes - that's a user definable parameter in the display. Turning the battery off and on again resets.

 

[matthewslack]

On mine the display will time out if it doesn’t see a wheel speed signal after 5 minutes.

The time out is adjustable on the display.

I use 2 magnets for the speed sensor to increase the magnetic field.


View attachment 59308

5 minutes! My Shimano doesn't give me 5 seconds! This starts to sound a likely cause.

 

[guerney]

battery has had very little use prior to bike build.

What voltage does your battery charge to?

 

[guerney]

5 minutes! My Shimano doesn't give me 5 seconds! This starts to sound a likely cause.

I should change mine to 5 minutes, 3 minutes isn't long enough waiting for traffic lights to change sometimes. Display shuts off and I have to enter the unlock code. During long waits, I turn the PAS level down and back up again every couple of minutes, to reset the count.

 

[Saracen]

hi all couple of short rides today ,first 2 miles ok,
second it cut out about 4 times , i do not think its magnat gap as the display would still be lit.
when it cuts out display is black, i have to turn battery off then on again ,display lights up then select pas level, ride again then it cuts out.
battery has had very little use prior to bike build.

if controller was faulty would i not get some kind of error code on display?

nealh i have a original tdz2. the only time i rode it home in heavy rain 3 miles, some days later the moter was making a rather graunchy sound, sent the moter to woosh to replace some bearings,

I had that problem it was a battery imbalance replaced under guarantee.

It is motor not moter

 

[guerney]

I had that problem it was a battery imbalance replaced under guarantee.

...and then you had this bad battery connection:

https://www.pedelecs.co.uk/forum/threads/100-no-idea.47366/post-716439

 

[Saracen]

...and then you had this bad battery connection:

https://www.pedelecs.co.uk/forum/threads/100-no-idea.47366/post-716439

NO the battery turned out to be faulty an imbalance in the cells

 

[guerney]

NO the battery turned out to be faulty an imbalance in the cells

Yes I've mistaken the replacement batttery you received under warranty, for your original faulty battery.

 

[it is i footpump]

hi all yesterday rode the bike,multiple cut outs about 8.
i was able to borrow a mates battery , same brand which fits onto my existing mounting bracket. and was fully charged.
rode the bike tried pas/throttle a hill 4 miles, no cut outs.

today recharged my battery not sure what a full charge should read, volt meter 48.9 i think. rode bike about 3 miles no cut outs,

so some thing must happen when battery gets depleted.
will try and see what battery reads when cut off reacure

 

[saneagle]

If it only charges to 48.9v, something is drastically wrong with it. Assuming a 48v battery, it should charge to 54.6v.

When the battery is empty, it's supposed to cut out!

 

[Ghost1951]

And if the cell groups are unbalanced, the BMS will shut off and the bike will stop when one cell group reaches the low point of about 3v. I think mine shut off when one group reached 2.9v.

Is this a new or an oldish battery? That charged voltage is very low. Probably too low to mean one cell group is a bit lower than the rest. Of course, if it was an out of balance issue, the charging would stop as soon as one cell group reached 4.2v or very near, so very out of balance groups would never get charged properly.

 

[lenny]

 

[it is i footpump]

thanks all dropped a clanger with voltmeter post, as my battery is a bit of a pig to remove from baseplate, have changed display to voltage, it is reading 53.6, it was not fully chaged prior to todays ride have put it on charge to see if it goes to 54.6
battery was purchased in 2021 but very little use .