Rechargeable batteries have become very good and very cheap. IKEA sells 4xAA batteries for 8€, made in Japan, last 500-1000 cycles. Many "non-user-serviceable"

Rechargeable batteries have become very good and very cheap. IKEA sells 4xAA batteries for 8€, made in Japan, last 500-1000 cycles. Many "non-user-serviceable" devices actually have them inside; they're just not accessible without breaking the plastic clips that hold everything together: https://www.pololu.com/category/54/batteries https://www.pololu.com/category/54/batteries