Two batteries in a laptop

[Guest]

What governs the handling of dual batteries in a laptop? How does the system
decide which to discharge when? Is it XP-controlled, or in the BIOS?

My current laptop fully drains the alternate battery before drawing on the
main one. I'm concerned that's bad for the alternate battery's life - it's
discharged deeply on a regular basis.

I observed on my last laptop in the same situation that the system would
alternate discharging each battery in increments of about 5% of battery
capacity. Thus each would be discharged approximately equally while on
battery use.

I'd like to get the same behavior with my current laptop but can find little
information on how best to do this.

 

[Og]

Dual- Battery usage is determined by the hardware configuration of your
laptop.
No version of Windows can effect changes to a computer's hardware wiring.
If your laptop has an option to make changes to battery usage, you will
learn about that feature in your laptop's manual or, alternatively, from the
manufacturer's technical support hot line.

Steve