How do I troubleshoot this one - battery or controller?

[leamcorp]

I've just received a BMC motor with 36v 25amp controller. Once installed, I've connected a 36v Lifepo4 battery and worked fine.

Then I've disconnected the 36v and hooked up a 48v battery - heard a sparking sound from the 48v battery (saw some smoke came out but couldn't see exactly where it came from). I've quickly disconnect and reconnected the 36v battery to see if I've damaged anything. I've some sparking sound also and disconnected from 36v battery.

I'm at a loss, now nothing will work - even my other motor/controller. When I connect the battery to a Cycle Analyst - it works fine up to that point (its a direct connect). When I connect from Cycle Analyst to a controller - I see some spark and Cycle Analyst shuts down.

Is it the battery or controller? I've checked all the connection/wire and even re-crimped a new end to make sure its not the wire.

 

[pwbset]

I've just received a BMC motor with 36v 25amp controller.

Maybe the controller FETs or caps aren't rated to 48v. That would be surprising to me because usually there is an overhead voltage buffer and 36v -> 48v isn't that much of an increase. That's a bummer. :?

 

[leamcorp]

I did open up the controller and it was potted - but I found the fets and it was rated to 62? (forgot now, but it was high).

Question - why do cycle analyst shut down when I connect the controller? I get no symptoms other than normal connecting spark? then it shuts down. and I have to disconnect the controller... disconnect the cycle analyst to battery and reconnect in order for it to come back online.

 

[dogman dan]

Was the 48v a lifepo4? Or just the 36v. Not impossible to have both bms and controller fried.

 

[fechter]

It sounds like the controller is shorted.

Disconnect the controller battery wires and measure across them in both directions with an ohmmeter. Normally, you would see a low reading that slowly increases in one direction.

If the controller is shorted, it will read pretty much zero in both directions.

I'm not sure if that controller is rated for 48v. Not only do the FETs and main capacitors need to have the right rating, but also the voltage regulator. Potted makes repair nearly impossible.

Warranty?

 

[leamcorp]

It sounds like the controller is shorted.

Disconnect the controller battery wires and measure across them in both directions with an ohmmeter. Normally, you would see a low reading that slowly increases in one direction.

If the controller is shorted, it will read pretty much zero in both directions.

I'm not sure if that controller is rated for 48v. Not only do the FETs and main capacitors need to have the right rating, but also the voltage regulator. Potted makes repair nearly impossible.

Warranty?

I think you're right - When I measured across, the reading is 000.2

When I measured another controller (WE BL) it measured 15.x K ohm and started going down.

I guess there's no way to revive this one? I've contacted the vendor and am now going through the motion.

As for the battery, I found the extent of the damage... the connection was burnt/severed and looks like BMS was fried. I'm slowly opening the battery to see what I could do. This is the famous Mr. JimmyWu's battery and I'll be taking the whole thing apart and re-assembling them. I'll start a another thread as this thing is very interesting - can any one say shoddy workmanship?

 

[fechter]

I would attempt a warranty replacement, but I would not mention anything about 48v :wink:

If that fails, or you just want a better controller, you could get one of the Infineon controllers from Knuckles.

 

[leamcorp]

I would attempt a warranty replacement, but I would not mention anything about 48v :wink:

If that fails, or you just want a better controller, you could get one of the Infineon controllers from Knuckles.

Thanks! I've already ordered one from Knuckles via ebay and just received a another 48v controller from E-crazyman. I've tried to get one of knuckles rear wheel kit before, but timing wasn't right. But I'll get couple of his kit before next season.

Now I just have to figure the wiring scheme for E-crazyman's controller.