Panasonic EY9231B 15.6-Volt 3.3 Amp Hour NiMH Pod Style Battery

The 3.5Amp Hour is the best battery Panasonic made for the older style 15.6V drills.
However, the best deal on these batteries is in the package of TWO. Don't make the mistake I did and buy two singles, instead get the discount by buying two at a time in one package.
These are very good quality batteries. Don't bother with the 3.0Amp Hour models, the slightly lower price isn't worth it in my opinion.

Panasonic EY9231B 15.6-Volt 3.3 Amp Hour NiMH Pod Style Battery

I've owned two Panasonic EY6432GQKW Drills for nearly 7 years; they use these batteries.

Run-time. For the first 5 years, drill run time was very good due to these excellent NiMH batteries and their high amp-hour rating. When not in use they maintain a charge longer than the several NiCad tools I've owned. On big jobs, I keep a spare Panasonic battery in the charger so it will be ready when needed. On a construction job when the Panasonic is used frequently, a battery discharges about once a day. On rare days, I change out batteries twice. The battery does not get hot sitting in the charger for hours (or even days).

Battery longevity. Batteries began to noticeably deteriorate after 5 years of serious use. At the 6 year mark, my two drills were still usable, but run-rime was ½ of what it was, drill speed was reduced, power is diminished, and the charge only lasted a week. By...Read more

Brought two replacement batteries in 2009...and they are not holding charge any more in 2011.only got two years thought I would get more life..the first two batteries did last longer and the drill is still good
As I am far away in the caribbean, think its Time to buy another brand...drill..