Windows 7: 9 cell battery not living up to its "potential"

i have a hp pavilion dv7-core i5,17.3" screen and the battery is a 9 cell li-ion-93hr but it can't go past 3 hours on battery power even on power saver mode and discrete graphics turned off(always on intel HD graphics)..is this normal?
i never game,just listening to music,watching movies and mostly browsing the internet.

It's impossible to say if it is normal or not because there are two many other variables that factor in. The only way to know for sure is if you had a lower cell battery to compare it to. Considering you have a 17.3" screen, 3 hours sounds like a great number. The larger the screen, the more power it draws. Typically, people with that large of a laptop screen aren't too concerned with battery power, as they aren't lugging it around that often. Those laptops are usually referred to as desktop replacements.

actually i underestimated it because today on a full charge i made almost 5(around 4 hours and 20 minutes) hours..but no form of gaming was involved.
thank you.

I'd call that stellar battery life on a large laptop.

One more query..is it possible to replace(at a future time) the 9 cell battery with a 12 cell battery?

If one exists, sure. The problem is, each laptop houses the battery cells in a unique compartment. That compartment is designed to fit into that specific laptop. If no one makes a 12 cell battery for your laptop, then you are out of luck.

In theory? Yes. If the producer's site does not sell them you need to google around with the full model name of your laptop (look at a sticker in the bottom side, not the one of Windows 7), and you likely get results like this, which are third party made batteries, that fit more than one model.

let me stress it check that your laptop's full model name is in the list of the compatible ones of the battery. Some have similar names, and it's easy to buy a battery that won't fit if you aren't VERY careful about that.

Another piece of advice, do not buy a battery and let it sit unused for years, keep using batteries at least once (full discharge and then full recharge) every 6 months to avoid them going bad. This is to stay on the safe side.

bob..that reminds me..i ran an energy efficiency report and found that i had some warnings..someone told me that one reason for those warnings is leaving the AC power supply plugged in even after the battery is fully charged..could that be a reason?
also does plugging the AC supply even when the battery is fully charged damage the battery over time?

depends from the warnings. Can you post them?

The main thing that damages batteries over time (other than using it of course) is heat from the laptop (or heat from direct sunlight, Kenya's sun should be pretty hot). As long as you can comfortably keep your hands under your laptop, you shouldn't need additional cooling, otherwise, you should invest in a cooling pad with a big fan (they are quieter).

The thing about leaving batteries while on AC is because doing so for extended periods of time will eventually screw the battery controller's opinion on how much the battery will last. (the battery controller is the battery's brain, so to speak, it's responsible of the correct operation of the battery's cells)
So it will report "battery near empty" when in fact it isn't true.
As long as you do a full discharge (you let the thing run until the battery actually runs dry, ignoring messages) and after that a full recharge per month or so, you should keep the controller's opinion close to actual battery capacity.

it is quite hot here but the air from the cpu fan is just slightly warm on batteries during the day but its cool during the night..
what part of the report should i post?