AA rechargeable batteries

My Sony rechargeable battery is half dead, all 4 of them, 2500mAh capacity. Each fully charge will power up 50 to 60 percent of the original power, even after a full discharge and recharge is the same.

Memory effect is a term that is thrown around with talking about a rechargeable battery, but there are a lot of misconceptions around what memory effect is. Memory effect is where batteries aren't able to hold as much charge as they once could. People are unnecessarily caught up stressing about memory effect, and things that look like memory effect. Duracell rechargeable batteries or any of the best rechargeable batteries will most likely do the job, so just run out and get some and stop worrying. Let's say you spend $20.00 on 4 aa rechargeable batteries and give them only 100 of the 1000 suggested charges over a couple of years, which they will easily achieve, each battery will end up costing 5c a charge ($20.00 / 4 / 100). Good luck finding single use disposable batteries at these prices!