BBS02b Failure

[peter.c]

Yes a very recent purchase late January ordered after Brexit, the replacement is fitted with a cable clamp and the newer fets

 

[egroover]

Although not ideal failing after only 800 miles, the price of a new controller at 75 quid is not a huge amount in the grand scheme of things. Imagine having the similar issue with an out of warranty bosch motor for example, and facing the possibility of having to buy a whole replacement motor at, what £600 or more?. I now run 2 bikes with bbs01b, I love em, great fun and no issues so far, fingers crossed, but love the fact they are easily servicable and parts are relatively cheap. if I was running a couple of £2k bosch powered bikes I'd be worried all the time that they might fail

 

[MontyPAS]

Just removed the controller and bone dry inside, no smell of "magic smoke".

 

[vfr400]

You have to measure it to see if it's faulty, not smell it!

 

[mike killay]

As the motor is in line of fire from the front wheel, some sort of shield would go a long way to reduce ingress I think.

A pet gripe of mine.
Modern front mudguards are far too short and should come to below the crank axle.
If you look at vintage bike photos you will see that they always did.
Quite where this modern fashion of inadequate mudguards came from I don't know, but I bet it was some idiot 'designer' who was more artist than engineer.
The fashion having been set, all the others slavishly follow.

 

[MontyPAS]

You have to measure it to see if it's faulty, not smell it!

Here you go VFR (needed new battery for fluke..... hence smell test!)

Yellow phase 9.65k
Blue phase 9.95k
Green phase 6.55k

 

[vfr400]

Here you go VFR (needed new battery for fluke..... hence smell test!)

Yellow phase 9.65k
Blue phase 9.95k
Green phase 6.55k

That's only half of them. Where's the other three?
Were all three phase connectors tight?

If the other three mosfet readings check out OK, I'm thinking it could be a problem on your 5v rail somewhere. You could start by checking the hall sensors switching, which is tricky because you have to turn the motor while it's connected.

I think I would start by checking out the pedal sensor

 

[MontyPAS]

That's only half of them. Where's the other three?

Yellow phase 9.65k to -ve
Blue phase 9.95k to -ve
Green phase 6.55k to -ve

Yellow phase 1.1m to +ve
Blue phase 1.1m to +ve
Green phase 0.7m to +ve
NOTE: All phases tests to -ve results are slowly increasing not stable.
Connect to -ve must discharge a capacitor on the PCB as it resets readings on the +ve to the lowest ohm reading .... ??

Edit: Tried a controller from my other BBS02 and unit is now working. So controller is Kaput?

 

[Nealh]

Looks like a fault on the green fet as the reading is way lower.

 

[MontyPAS]

Looks like a fault on the green fet as the reading is way lower.

Yep!
Tried a controller from my other BBS02 and unit is now working. So controller is Kaput?

 

[egroover]

Should be covered by warranty, only 8 mths old? Let us know how you get on with the warranty return

Warranty Policy

Bafang description

bafang-e.com

 

[MontyPAS]

Should be covered by warranty, only 8 mths old? Let us know how you get on with the warranty return

Warranty Policy

Bafang description

bafang-e.com

Just spoken to the UK supplier, very helpful and sending back faulty unit (hopefully a replacement)

 

[vfr400]

Yellow phase 9.65k to -ve
Blue phase 9.95k to -ve
Green phase 6.55k to -ve

Yellow phase 1.1m to +ve
Blue phase 1.1m to +ve
Green phase 0.7m to +ve
NOTE: All phases tests to -ve results are slowly increasing not stable.
Connect to -ve must discharge a capacitor on the PCB as it resets readings on the +ve to the lowest ohm reading .... ??

Edit: Tried a controller from my other BBS02 and unit is now working. So controller is Kaput?

Yes, there's a big capacitor across the positive and negative wires that gets charged from your meter, which is why the values climb. the important thing is that all three are the same. When they're blown, you normally see more of a difference than what you measured, but clearly something isn't right.

As it's going to be difficult to check everything else, I think I'd go for a new controller first. While you're waiting for it, you could take out the PAS to check the pcb and wiring, which will give you a chance to put loads of grease where it's needed.

 

[egroover]

Just spoken to the UK supplier, very helpful and sending back faulty unit (hopefully a replacement)

Sounds promising, sending back just the controller or the whole motor? Hope the supplier comes good. Please name check them here if you end up getting good service so others can consider them for future purchases

 

[MontyPAS]

Sounds promising, sending back just the controller or the whole motor? Hope the supplier comes good. Please name check them here if you end up getting good service so others can consider them for future purchases

Just the controller as I've proved it faulty by substitution (#28).
Will let all know the outcome with the supplier, they have been very good in the past.

 

[MontyPAS]

Just the controller as I've proved it faulty by substitution (#28).
Will let all know the outcome with the supplier, they have been very good in the past.

After returning the controller back to the UK seller, no fault was found. The intermittent fault turned out to be with the display unit. Swapped with a spare and back in business.
Thought the resistance measurements were too close and inconclusive.
HoHum live and learn