This 3.7V Li-po Battery should give you about 12 minutes of playtime before needing a recharge. Please fully charge this battery before first use, and thereafter before and after use. When the vehicle starts to slow down. Stop and turn things off. Let the battery cool down for 10 minutes before recharging or damage may result. If putting a second battery into the toy, please let the motor have a 5-minute break to cool off before beginning using the second battery or damage may result. When plugging your battery into the vehicle or the USB charger, please be careful, it only plugs in one way. Please don't pull on the wires when unplugging the battery, they will break easily. Unplug by pulling on the two connector halves. Your MINI should move at up to 12 MPH with the fully charged battery.
With your USB Charger plugged into a power source of no more than 5V 2 amp output, the charger's power light will remain off. With the depleted battery installed now, the USB power light should come on solid red until finished charging when it will turn off. It should take about 20 minutes to recharge, not 120 as mentioned in the Start Guide.
If you have or know someone that has a multi-meter your 3.7V Li-po battery should read 4.2V when fully charged.