AA and AAA NiMH low self-discharge tests--Round 2

Started Dec 18, 2007 | Discussions thread
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archae86 Contributing Member • Posts: 658
AA and AAA NiMH low self-discharge tests--Round 2

Low self-discharge battery tests--Round 2

In a previous thread, I provided test results and interpretative observations on a few brands of AA and one brand of AAA low self-discharge NiMH batteries.

http://forums.dpreview.com/forums/read.asp?forum=1023&message=22988426

People posting in that thread pointed out that there are some new brands since my first selection. Also I've gotten some encouragment from people finding those measurements and postings useful.

So I've purchased 4-sets of six different as yet untested brands of AA and sets of five untested brands of AAA, and intend to test them in very similar style to my first round of tests. I intend to present the results for all eleven sets of AA and all six sets of AAA together (rounds 1 and 2), to ease comparison.

I'll document my intended methods at the start here, and plan to myself initiate several subthreads:

1. Methods--as I can't edit my posts, this thread will document any changes or added detail to my plans from this post--also any further added brands.

2. Graphs--I'll make a post here for graphs which compare capacity and retention by readout by brand. These are intentionally not in the first post, so folks won't be waiting for them to load each time they visit the thread. I'll use GIF format for the images of the graphs, and expect download size on the order of 10kbytes

3. General discussion and interpretation--for overall comments about this sort of battery, the testing and methods, references to test results posted by others...

4. Initial Readout--Capacity measured on the fresh batteries as received.

5. One hour retention--the capacity measured after a round of breakin cycling, then a standard charge, with a one-hour delay from end of charge to start of discharge. The number logged at this readout is the reference for percent capacity retention at longer hold time readouts.

6. One Week retention--no further cycling, just a standard charge after the one-hour discharge. Hold time from end of charge to start of discharge very close to 168 hours.

7. Four Week retention--similar interpretation to one week, but without so much care given to matching the hour of the day.

8. Three month retention--again like One week, intended to start discharge 91 days after charge, but some errors up to three days have happened.

Schedule--rough estimates
Intial readouts, time zero, oneweek--December 18, 2008
Four week--January 25, 2008
Three month--May 1, 2008

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