Car camping and charging electronics

Hi y’all I’m new to hybrids and to the cx50! I’m planning a car camping trip. Can I charge my phone using the port in the back of the car when I’m sleeping or will that somehow damage the hybrid battery? It has power even without the car being in accessory mode, but the rear hatch was open. I’m not sure what happens when I close the rear hatch to sleep and whether I can still charge. Thanks for any experience and advice!

ETA: I have an external battery I use when tent camping and I can definitely bring that. I’m more just curious about whether the hybrid battery can be used in this way or if that would damage it. Thanks!!