Upside to K-x AA Batteries

Started Nov 20, 2009 | Discussions thread
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mamiller Regular Member • Posts: 200
Upside to K-x AA Batteries

Not to minimize the annoying problems some users have been having with batteries in the K-x -- problems we all hope will be addressed soon by Pentax -- but I wanted to put in perspective the upside of using AAs in this camera.

A robust shooter like the new Nikon D300 comes with a 7.4 volt proprietary lithium battery rated at 1500 mAh (11.1 watt hours), supposedly good for 950 shots. The Pentax K7 uses a 1400 mAh 7.4 volt proprietary battery (the equivalent of 10.36 watt hours), good for about 740 shots. These are excellent batteries when fresh off the charger, but lose charge each day and their performance degrades over time as the batteries get older. Plus, the batteries cost $40 or more.

The K-x uses any type of AA battery with a voltage between 1.2 and 1.6. With the right set of batteries, the K-x should be able to outperform these big brother cameras in the field in terms of number of exposures.

A typical NiMh Hybrid AA battery has a rating of 2100 NiMh (1.2 volts). A set of four is the equivalent of 10.36 watt hours. Not bad, especially for a battery type that holds on to its charge when left in the camera.

Plain old NiMh batteries are available with mAh ratings of 2700 and more. A set of four 2700 mAh batteries is the equivalent of 12.96 watt hours. Fresh off the charger on a one day shoot, these should easily handle more than a thousand shots in the K-x. That's awfully damn good! However, once out of the charger (in a bag or in a camera) even when not in use, they will lose a a small percentage of their charge each day. Also, like the other rechargeable battery types, both lithium and NiMh,, the performance of each battery cell degrades over time and capacity diminishes.

Nonrechargeable lithium batteries (the best are made by Eveready and are labeled "Energizer Ultimate Lithium") are 1.5 volt batteries rated at 3000 mAh. A set of four produces the equivalent of 18 watt hours of energy. 18 watt hours and they don't leach a charge!! These batteries have a 10 year shelf life, operate in extreme cold, and are very light in weight. They are a great choice for the casual photographer who expects to take a few hundred photos each month and doesn't want to mess with changing batteries all the time or worrying about chargiing batteries every time they want to use the camera. They're also a great choice for travelers and for hikers, or for an intensive weekend of shooting.

I like to use the hybrids around town, with lithiums as backups. On the road or on the trail, I use lithiums.

AAs = freedom of choice!

11.10 watt hours -- Nikon D300 Battery
10.36 watt hours -- Pentax K7 Battery
10.08 watt hours -- Hybrid AA's (2100 mAh)
12.96 watt hours -- 2700 NiMh AAs (not Hybrid)
18.00 watt hours -- Energizer Lithium Non-Rechargeable Batteries

Here's to hoping Pentax irons out the kinks in its firmware soon --


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