The best battery life I've ever had is the Xinhuang CR1220's (flat, dime-sized) that I bought for the built-in tuners in both my Strats. I paid about 8.00 with free shipping for two cards of five batteries each. I still have three left after almost 11 years. Every once in a while, Chinese batteries surprise me. I've had mixed success with the lithium battery packs I buy on eBay for my Pentax cameras. I've had a couple that failed, but seven have lasted several years and still recharge fine. In the early 80's, the audio store I worked at sold Maxell batteries. I don't know who made them for Maxell, but they lasted about twice as long as comparable Duracells and Energizers.