@styrkjar not sure how your AA battery pack was created but [https://www.batteryspace.com/custom-nimh-battery-2-4v-4-0ah-9-6wh-8a-rate-2s-s-rechargeable-battery-pack.aspx|this one] should work. However, for the price of it I’d be learning to solder pretty quick to save the money. Not pretty but [https://imgur.com/gallery/ucBxugN|this could] work. The original battery for this is a Samsung 22F 18650 Battery like [https://voltaplex.com/samsung-22f-18650-battery-icr18650-22f|this one]