The 18650 lithium battery is 3.7V 3AH. Use 40 batteries and connect each 10 in series to become 37V3AH per group. Then these 4 groups are connected in parallel to become 37V 12AH. It's very inconvenient, 40 batteries require soldering. soldering iron and if there is a problem with an individual battery, it will affect the overall performance.
The main problem you mentioned is that the total mileage of the car does not match the calibration, i.e. calibration. Battery power does not meet the design standard. Lithium batteries are usually sold alone. They benefit from a two-year warranty from the date. If it only takes three hours to fully charge after being discharged, it is abnormal. go to the store and follow the instructions or ask the seller directly to see if it is correct.