Inspiron 8500m Laptop Battery Tips:

How to choose between two batteries with different Watt hours (Whr) or
milliAmpere hour(mAh)?
Higher Watt hours (Whr) or milliAmpere hour(mAh) on the same system
under the same operating conditions means longer battery run time. For
example, if you compare the same system, running the same
applications, the dell inspiron 8500m battery with 73Whr would provide
approximately 37% more run time than the 53Whr inspiron 8500m series
battery.

How to keep my battery healthy?
Inspiron 8500m battery packs should be charged for 12 hours when you
first get them. Laptop batteries are completely discharged at the time
of purchase, and need a full charge before their first use.

How to deal with the my dell battery when it is not used?
Do not leave your inspiron 8500m battery inactive for extended periods
of time. Even if you use AC power most of the time, use the battery
periodically to keep it in good condition. Unplug your AC adapter when
the computer is not in use to prevent overcharging.

What should I do for battery storage for a long period of time?
Do not store your inspiron 8500m battery for long periods plugged into
or attached to any power source,including AC adapters and laptop
security carts plugged into an outlet; Charge batteries before
storing. The recommended charging time should not exceed 1 hour.

How to maximize my dell inspiron 8500m battery performance?
To get maximum performance from the battery, fully optimize the
notebooks power management features prior to use. The power management
system conserves inspiron 8500m battery power by setting the processor
to run at a slower speed, dimming the screen, spinning down the hard
drive when it's not in use and causing the machine to go into sleep
mode when inactive.

reference:
http://www.cheap-pda-batteries.co.uk...0m-series.html
http://www.laptop-battery-inc.co.uk/...00m-series.htm
http://www.power-batteries.net/noteb...0m-series.html