If you got the basic package, the only way to charge the batteries is by inserting them in the drone. This allows up to three batteries to be charged along with the controller be aware, this does not have a charger, it requires a charger that has a minimum of about 18 watts of output. A simple usb charger from a phone or the computer may not work. I have the zendor charging base. It has two outputs that can be used for 100 watts of charging and 18 watts. This one works fine with this device, so it is a simple and easy to use device for charging the batteries and the mini drone controller. Make certain you have a good charger arrived in perfect condition, very easy to use and works as described kind of expensive for what it does, but it’s a great asset for all mini owners. A must have item for dji mavic mini great product Music. I understand what this does, but it feels very, very thin and weak. I haven’t had it long and have not used it. I took it out and examined. It looks well made, though this is an amazing idea by dji a triple battery charger that also functions as a power bank and can charge attached items like the controller, sheer genius, since i always have one of my three batteries in the mini. I have 3d printed.