Batteries... rechargeable or not?

Jenia Ciomek & I had a discussion on January 7, 2007 about rechargeable batteries. Since I suspect that battery issues come up quite often, I thought it would be a good idea to add some information here.

I have no personal experience with rechargeable "regular" batteries (as in AA, AAA, and other similar batteries) since my cameras use proprietary batteries - but I was able to find what appears to be a good source of information on this type of batteries, an article . Digital cameras (other than SLRs) do have quite a habit of eating batteries, and if your camera uses non-proprietary batteries it still may be a good idea to use rechargeable batteries.

I found a series of web pages written by someone who is touted as being "an avid user of rechargeable batteries". The pages are posted on the web site of the California Integrated Waste Management Board and include information on NiCd and NiMH batteries plus links to sources for both battery chargers and rechargeable batteries.

www.ciwmb.ca.gov/WPW/Power/RechBattInfo.htm

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The following information on rechargeable batteries was provided by Brian Huntley on January 7, 2007.

1. The capacity numbers do make a difference. They're typically made by computing how long the battery would take to discharge at some percentage (30% I think) of their rated load. The load/life graph isn't a straight line for these, so if you're hitting the battery with a lot of short sharp loads, a larger mAH rating will go a lot farther. One set of 2500 mAH cells will, for example, way outlast three sets of 800 mAH cells, if used heavily.
   
   
2. Flashes and zoom lenses are heavy loads. Cameras in general are heavy loads, but zooms and large screens and flashes really add up.
   
   
3. NiMH batteries self-discharge fairly quickly, so if you charged both sets at the same time, then used one the same day and the other the next, the second set would be at a disadvantage. It's a good idea to top them up immediately before use, if possible. Higher capacity batteries may self-discharge faster initially in the same way a hot coffee loses more heat per unit time than a luke warm cup.
   
   
4. Some chargers may shut down charging too early if you mix batteries that need different amounts of charge. If I have to charge 2000 and 2500 mAH cells at the same time, I'll always put the larger ones back in for a bit (with the 2000s removed) after the charger shuts down.

These days, I avoid anything but the highest rating batteries I can find. It's easy to find 2500 mAH AA cells, and 3000s are available. I'd like to find one of those micro-chargers that's not much bigger than a pair of cells, for on-the-road use. If I only charge the pair from my camera, I'm not too concerned about the bells and whistles of the charger. Oh, and don't leave your unloaded NiMH charger plugged in/switched on - it's a bit of an energy hog even when idle, as it has sensors and such that are continuously cycling.

End of information supplied by Brian Huntley