The manufacturer does not disclose the capacity. However, it mentions the following regarding capacity: "The GB30 itself contains a lithium-ion battery that holds its charge for a year and is sufficient for up to 20 start-ups".

Hello Peter, I'm not part of the Galaxus team, but I'll answer your question anyway. You can charge the Booster like a mobile phone via a USB cable (included in the delivery). Also included is a cigarette lighter adapter, to which you can also connect the USB cable and thus charge the Booster directly in the car. Greetings