Using the Bosch GAX1218V-30 charger is easy. First, make sure it's plugged into a power outlet. Then, you can insert either a Bosch 18V or 12V Max battery into the charging bays. If you want to charge your mobile phone or other device, just connect it to the 2.1 amp USB port. The LED indicators will show you the charging status. While charging, keep the charger in a well - ventilated area and away from flammable materials. Don't expose it to water or extreme temperatures. After each use, you can simply unplug it and store it in a dry place. Periodically check the cord for any signs of damage. If you have any issues, refer to the warranty details at https://rb - pt.io/PowerToolWarranty or call 1 - 877 - BOSCH99.