The Esc in question is a Hobbywing-Skywalker 40A. I just connected the battery, It gave the startup tone and then just smoke. I disconnected the battery and checked all the connections for shorts and reverse polarity, but everything is correct. I connected my Hobbyking 30A, to the same setup and it worked fine.
Any ideas anyone? did I miss something?

Ashim.

Remove the heatshrink, post a pic as it will help to perform post-mortem. There are many components that can fail so would be hard to pinpoint exactly what went wrong.

If you can claim a replacement/warranty then dont remove heatshrink.

No warranty picked it up from a rcindia member.

Just wanted to know, did you try to re-connect it again?

Both the esc's support 2-4S lipo.From the pics cant make out much. Just take a closer look and see if you can find anything burnt, blackish/brownish colour.And try to remove the heat sink, maybe something must have burnt under it.