Hello,   This are the 2 part numbers for the batteries that we used on the M17X R1: W075J and C852J. Because of the age of the computer, as you said, we don’t have stock for that unit any more. You can look through third party or online stores and see if they have any available.

I wouldn’t be able to guarantee that they would work, or which part numbers to use because it’s not something that we’ve tried before. You could be able to try batteries from the R2 and R3 series, or maybe even from the M15X R1, but again I’m not sure it they would work. You could also try posting this on the Notebook Review and Alienware Arena forums for further information on it.

Thanks, I'll browse and post there and see if I can gain any additional direction. Any recommendations on legit third-party battery companies? There seems to be a lot of scammy garbage out there in the battery world, tough to tell what's real and what's not.

There seems to be a lot of scammy garbage out there in the battery world, tough to tell what's real and what's not.

Exactly.

Try these guys. I bought a Dell M65 Mobile Workstation (laptop) battery from Denaq years ago and it still works great.

http://www.denaq.com/

We don't have any recommended companies. Just check online, that's the easiest way to find them.