Jon - For audio files, I wouldn't use anything but lithium ion batteries. I buy them at Sam's Club in quantities of 12 batteries at a time (it's a pack of 3 packages of 4 batteries). I get excellent performance using these with all types of books, particularly books from Audible.com, and they're all I use nowadays. If you opt to go with rechargeables, I strongly recommend the 15-minute rechargeables. I think they're made by Ray-O-Vac and while RadioShack used to sell the chargers packaged with one set of batteries, I've seen others say here that they no longer seem to carry them. These are nice and will certainly cut away down on land fill pollution, but you won't get nearly the per-charge playing time that you will with a set of lithium ion batteries and if you travel anywhere away from home with the Book Port, you'll need to carry the charger and look for an a.c. outlet to recharge when the batteries run low. These 15-minute rechargeables require a special charger; that is, you can't charge them in any old charger that accepts double A batteries; and while the chargers for them will accept other types of rechargeables, you don't dare mix battery types during a recharging cycle. They really do recharge in 15 minutes, too. ----- Original Message ----- From: "Jon Hodgin" <capiscum@xxxxxxxxxxxxxx> To: <bookport@xxxxxxxxxxxxx> Sent: Saturday, February 10, 2007 10:18 AM Subject: [bookport] batteries Mostly, I use book port to read audio files on the book port. As you know, battery cost increases sharply. What do some of you do to improve performance and battery life when you read audio files? Do rechargeable batteries improve cost? Do rechargeable batteries perform well? Being a frugal old tightwad, I would appreciate a discussion re: using batteries with audio files. Thanks much, John