Tested charging speed (Input and Output) and it works great. Charges and outputs at 55-60W. I tested the capacity 3 times and found it to be average of 30.54WH. The rated capacity is 31WH so I found that great as there is often a difference of about 20% on a lot of batteries sold online. Starts my 2.6L car super easy. Would recommend, make sure to store it somewhere above -10C as these will struggle when cold.