OEM Battery or Replacement battery made by other company?

i am try to buy a 9 cell battery for my t400. i come a cross a lot of different kind of battery that re-brand or battery not make by Lenovo. i like to ask you guy some opinion.

 

Performance is pretty much the same. What has kept me away from non-Lenovo batteries is the nagging that the Power Manager software sends your way for not using Lenovo-genuine parts. Of course, if you don't use Power Manager, you could probably save some money by going third-party.

 

Lenovo battery cells are made by Sanyo, Sony, Panasonic and some instances LG. While, aftermarket battery usually use cells from small factories, to keep the cost down, but the quality also suffers, which may lead to 1) shortened battery longevity 2) shortened battery life 3) overheating 4) in the unlikely event explosion.

Also, Lenovo battery prevents 3) and 4) through onboard controller IC that monitors the charge and temperature through thermoprobes placed on the battery cells. If it detects anything outside of the normal battery usage and charge parameter that may lead to explosion or meltdown, then it will trip the safety and prevent the battery from been further used.

This feature is not found on aftermarket batteries.