|Why would you double what you're getting from what I presume is a battery that's old enough it should have been replaced by now to determine how long a NEW battery with twice the capacity would last?|
If your battery is more than two years old, and if you need the run time to be as long as possible, you probably need a new battery.
See response 1 in this:
I have replaced 2 for others, one in a Compaq, the other in a HP, with a clone 12 cell battery. At just under and just over two years, the original 6 cell battery was crappy by that time.
You don't necessarily have to get the HP/Compaq one - in fact they don't list a 12 cell one for your model - there are lots of clones out there - just search the web with 12 cell and your laptop model number. HP warranties theirs for only a year, all of them are made in china, so any clone that has a 1 year warranty is just as good.
You can get a clone 12 cell for a lot less than a HP 6 cell.
Depending on which 12 cell battery and what individual cells it uses and how much current your latop requires you get as much as 6 hours run time when it's new.
The 12 cell ones protrude from the battery slot about 5/8" at the back rather than being flush to the case, and their enclosure is slanted so the laptop rests on the battery at the back and the bottom front of the case at the front .