i know that ibm thinkpads has an advanced battery charging scheme.  it allows you to set a battery threshold % so that unless the battery reaches that %, the system will never charge the battery.

 

ie.  i set it to 20%.  i start with a 100% full battery.  i use it to 80%, plug in.  now normally, the battery would start charging, but since i set the threshold, the battery *does not* charge.  although the battery is not full and the laptop is plugged into the ac, it does not charge.  i can then remove the ac and use it to 18%.  then if i plugged in the ac, the battery would charge. 

 

i like this feature because for those of us that constantly switch from ac to battery, it will save *a lot* of recharge cycles and extend the overall life of the battery.

 

do dell laptops power management hardware/software support this type of function?

 

thanks.