Dying Controllers

[OldHamster]

I’m running a 36V system with a 250W front hub motor. The issue that I’m having is that the controllers are dying . The first one which came with the kit died at around 2,000 kms, the second which was supplied as a replacement also died at the same distance and my third one has lasted better but has also passed away at just over 4,250 kms.

When they die the bike will start out performing perfectly, but will lose power completely then after a minute or so it will regain power and so on in that fashion with the periods of no power lengthening until basically nothing happens at all. With a replacement controller all becomes good again until of course that one fails .

Any suggestions as to why this is happening or a robust failure-free controller would be appreciated.

 

[Drunkskunk]

Off hand, it sounds like they are getting baked. It would help to know what brand and model you're using. It would also help to know how you have it mounted.

I've never had an Infineon die. I've only killed 1 Clyte analog, and that was from water entry. I one that dates back to 2007, and a couple that date back to 2008 with many 1000s of miles on them.

 

[icecube57]

Is this a brushed motor?

 

[OldHamster]

Is this a brushed motor?

It's a brushless motor. It's mounted inside a plastic box that part of the battery assembly so it's not getting any airflow so my current thinking is that they are getting cooked.

 

[DAND214]

When they die have you touched them to see how hot they are?

I would go along with the well baked theory.

Dan

 

[OldHamster]

I’ve never touched it after it’s been working, but when it’s merely connected to the battery it’s warm to the touch. So I’m thinking that when under load it probably is getting hot.

My 12A controller died after only 2,000 kms and the 17A needed 4,250 kms to kill it. My current plan is to replace it with a 22A and to place it somewhere that receives a good airflow. I’m even thinking of attaching some sort of heat sink to ensure that it stays cool.

 

[amberwolf]

I'd also say being cooked is likely. They'r eprobably all fixable, and what usually goes first when cooked is the can-style capacitors. That might be all that's wrong wtih them, but if not t could be the FETs or the low voltage regulator (which doesn't have a heatsink directly to the outside most of the time so it just heats up the inside air of the controller, which heats up the other components, etc).

Controllers inside bags or boxes with no heat path to the outside are good candidates for eventual failure, if not immediate.