Modding Battery Packs

Did you know that the battery packs in many of your home tools and gadgets are just a bunch of rechargeable batteries inside of a plastic pack — and that the batteries that are used are usually on the cheap side (leading to less than spectacular batt life)? And, did you know that you can open that plastic case and replace the existing batteries with better ones? This Instructables project shows you how (on a cordless drill batt pack).