Secondary Battery Charging Issue

[Dirac]

I recently purchased a HP ST09 Extended Life Notebook Battery, but it is not charging how like I would expect and causing me some grief.   My computer is a Zbook 15. 

Both batteries are detected by my Windows 7 operating number, however when an AC adapter is connected only the original battery charges.  This way in order to charge the secondary battery, I need to physically disconnect the original battery and have only the ST09 in.

This is a very annoying procedure to have to do everytime the secondary battery runs out of power.  Is there anyway for both to charge at the same time or just the secondary battery charge when both are connected?

[Dirac · Accepted solution]

Ok realized something that essentially solves the problem. There's a "Secondary Battery Fast Charge" feature that can be enabled in the BIOS that stops charging the primary battery at 90% and begins charging a secondary battery to optimize the charge cycle.

Neat