Whether looking to upgrade your fat tire eBike battery or you want to get a backup for your trips into the backcountry, our 21ah Battery is the perfect solution. With a battery life of 900 charges, this extended distance battery will improve your rides for years to come. There are a number of variables that can affect the range of your electric bike battery including but not limited to rider weight, temperature, level of pedal assist, and terrain. Click here to learn more. A 21ah Bakcou eBike battery is equivalent to 1008 watt hours. For more info, please refer to this post. This battery fits into KING KONG style Scout frames only. 21ah batteries WILL NOT fit into Pathfinder style frames. If you&';re unsure of what frame style you have, please reach out to Bakcou&';s Customer Service Team.