We have all used standard rechargeable batteries in the past. You are going to need a decent charger for them. The USBCELL AA Rechargeable Battery is quite special though. It works like a regular AA battery but can be charged using USB power. They can be recharged hundreds of times and have an intelligent charger. These batteries don’t have “memory” problems. You can get a USBCELL AA Rechargable Battery for around $18.