Using your CNHL Racing Series 9500mAh 14.8V 4S 90C Lipo Battery is easy. First, make sure the voltage and plug of the battery match your RC car. When charging, keep an eye on the cell voltage. Stop charging as soon as it hits 4.2V, as the normal cell voltage is between 3.7V and 4.2V. Before using a new battery, take a quick look at its surface to make sure there are no damages and check if the voltage is normal. If you find that the battery can't hold a full charge or loses charge very fast, don't worry. Just use a Balance Charger to charge and recycle it a few times. This will help bring the battery back to good condition. And remember, always store your battery in a cool and dry place to keep it in top shape for your next RC adventure.