New Inspiron DIED 3rd month, fix was to pull battery ??

Inspiron 16 7640 2-in-1 wouldn't power up one day for unknown reason. Under warranty I sent to DELL which have really been great I will say however they say the repair was ..

Specifically, the following parts were replaced during the repair process: Reseat Cables for No System LED indicator.

So that sounds like they just pulled the battery for a few seconds?

Sent across the country just for something we use to be able to do in seconds -- pull the battery. 

Why did it happen in the fist place? 

Should I be keeping the power plugged in when not in use? Using the C-Type I'm sure they will eventually get loose and need replacement which Is why I just leave it plugged in. 

I assume if I  pulled the cover and power connection on my own or will I have to ship it to Texas each time to avoid voiding the warranty? 

Thanks :)