More Bafang BBSO2 problems

[brianw]

Since my last post in April/May I have replaced a controller(cpu)
and display unit (lcd) on a bike I sold to an inexperienced
rider who fried the cpu and lcd by over voltage.Let's call that
bike A
I have been riding my wife's identical bike (let's call it bike B)
since then. Last week on holiday I connected my LiPo batteries
with the Andersen connectors, in the normal way, as I have done
many times. and there was no lcd display. I repeated this many times on
holiday with no effect.
When I got home I connected new lcd from bike A and after powering up
as normal with all functions showing I got an error message 50-
communication error. So I switched off and tried again with the
same result. Not wishing to do any more damage I disconnected the
batteries.
Next I tried the lcd from bike A on bike B, nothing. Next I
swapped every combination of cpc, lcd and cables and batteries and
leads, nothing.
Thinking over all these actions, the only difference I can recall is
a louder 'smack' when I connected the Andersen connectors, than I
remember/sense than before, although this smack sound does vary
from one time to another. I don't know if this is significant.
Any ideas on what has happened or suggestions of more tests I can
do?

 

[Nealh]

How did you wire up the lipo's are you sure you also haven't overvolted and blown the controller.

Check the power poles for damage or shorting due to spark damage.
The crack is the sound of the voltage rush as the capacitors charge up in the controller when connect up.
Most likely cause is damaged controller, remove controller to look or smell for damage.

For me lipo's are generally history and now prefer Li-on cells.

 

[brianw]

How did you wire up the lipo's are you sure you also haven't overvolted and blown the controller.

Check the power poles for damage or shorting due to spark damage.
The crack is the sound of the voltage rush as the capacitors charge up in the controller when connect up.
Most likely cause is damaged controller, remove controller to look or smell for damage.

For me lipo's are generally history and now prefer Li-on cells.

Thanks for your swift reply


As I said I connected the Andesen black/red fixed pairs of connectors as I have for three years. It is difficult to connect red to black.
Looking at them now one black and one red of the set I used on holiday, is lightly pitted, but you say this would be the result of a normal voltage rush.
Are you saying the cpu can blow each time I connect batteries and I've blown two cpu's and lcd's without riding my bikes?

 

[Nealh]

It shouldn't do.
What voltage lipo's are you using.
If there's no power at the lcd then the fault is from battery to controller output.
Check the battery discharge to make sure you have power, if so then you will have to take a look as I mentioned at the controller.
Also do use a fuse between battery and controller ?

 

[brianw]

It shouldn't do.
What voltage lipo's are you using.
If there's no power at the lcd then the fault is from battery to controller output.
Check the battery discharge to make sure you have power, if so then you will have to take a look as I mentioned at the controller.
Also do use a fuse between battery and controller ?

Just checked voltage at 5 pin connector to lcd
With alignment arrow at 12 o'clock and numbering anti clockwise, I get 40 v between 1 an 3 and 1.8 v between 1 and 2
Back to over voltage, I only use two 5C LiPo's so fully charged voltage can only be 2x21 v
If the fuse you refer to is an inline fuse in the positive 42 v supply? what ampage would I need?
If I solve this problem I want to take all steps to prevent a reoccerence

 

[brianw]

It shouldn't do.
What voltage lipo's are you using.
If there's no power at the lcd then the fault is from battery to controller output.
Check the battery discharge to make sure you have power, if so then you will have to take a look as I mentioned at the controller.
Also do use a fuse between battery and controller ?

Now tested voltage on bike A . It has 40 v between 3 and 1 and 3 and 5

 

[Nealh]

Comms error code usually mean controller issue, they can be flaky on the BBS01.
You will for sure have to remove the controller to have a look as mentioned and see if anything doesn't look right to the eye, other wise it is all potted in rubber latex.

Fuse wise use a rating a bit more then the amp rating of the controller so 20a gives a bit of head room, a 15a one will most likely keep blowing. Also use XT90 anti spark connectors, still waiting for XT60AS to appear.

 

[awol]

For me lipo's are generally history and now prefer Li-on cells.

I was thinking that until I started using my Speedict Neptune15 BMS with my lipo's. I now use them as a normal battery with normal charger and when they eventually need renewing there is no spotwelding or anything, just unplug old blocks and plug on new ones.

 

[KirstinS]

I was thinking that until I started using my Speedict Neptune15 BMS with my lipo's. I now use them as a normal battery with normal charger and when they eventually need renewing there is no spotwelding or anything, just unplug old blocks and plug on new ones.

Hi awol , that’s a nice bms ! But I’m still with Neil . The times they are a changin’

Just seems to me that the advantages of lipo (small size vs capacity and desired c rating vs smaller cost )of a few years back have all but evaporated .

It's the longevity that gets me . Yes multistar are still cheap on a deal but they die so fast. I've gone through 8 packs with minimal use on 250w systems (all 6s or 4s between 5 and 6ah)

Add in some hassle (for most users who need to take time and effort with balancing , wiring harness etc)

Plus the danger factor

And I'm left with .....just buy 30q and be done with it !





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[awol]

Hi awol , that’s a nice bms ! But I’m still with Neil . The times they are a changin’

I'm not 100% lipo's, I have several to use up from when they've been on sale. I am still planning a spotwelded battery project in the near future - I want to build a drinks bottle battery so will be looking for help on that when that time comes.

 

[KirstinS]

I'm not 100% lipo's, I have several to use up from when they've been on sale. I am still planning a spotwelded battery project in the near future - I want to build a drinks bottle battery so will be looking for help on that when that time comes.

D8veh did a really good post on just that , maybe a year ago ? I'll try to find it


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[KirstinS]

Here it is. Meant to have a crack myself but haven't found the time

https://r.tapatalk.com/shareLink?share_fid=19542&share_tid=28437&url=http://www.pedelecs.co.uk/forum/index.php?threads/How-to-make-a-lightweight-battery.28437/&share_type=t


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[brianw]

Hi awol , that’s a nice bms ! But I’m still with Neil . The times they are a changin’

Just seems to me that the advantages of lipo (small size vs capacity and desired c rating vs smaller cost )of a few years back have all but evaporated .

It's the longevity that gets me . Yes multistar are still cheap on a deal but they die so fast. I've gone through 8 packs with minimal use on 250w systems (all 6s or 4s between 5 and 6ah)

Add in some hassle (for most users who need to take time and effort with balancing , wiring harness etc)

Plus the danger factor

And I'm left with .....just buy 30q and be done with it !
Did you read my original post and have you had problems with cpu's or lcd's?
My reply did'nt post completely. what are 30q?




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Very interesting to read your post but what is 30q?

 

[Nealh]

Very interesting to read your post but what is 30q?

Samsung 30Q cells , 3000mah 15a rated.