I wanted to share a good experience sourcing a battery for the Dell Mini 9.
This June I bought this battery
https://www.amazon.com/gp/product/B00RBHGWRK/
from seller CSEDirect
and 6 months later the battery is still running great / I get hours out of it.
Really seems to be a new build of the battery and not NOS that has sat for years and years on a shelf and become useless.
I am also using this charger:
https://www.amazon.com/Power-ELE-Ada...dp/B002U1Z9BC/
Seller is Power ELE.
I hope this helps someone out!