I use a 200 watt inverter on a 12 V outlet to charge electronics. But the outlet is hardwired in to a fused circuit. The inverter has a male 12V "cigarette lighter" plug. It has 2 110 V outlets and a USB. I've charged 2 phones at the same time. If charging a laptop, I don't plug anything else in because the laptop uses more current.
No need for a bunch of extension cords. Put a 12 V outlet where you want it. If you can fish wire to rig it like you have it, you can install an outlet. But the outlet should be on a fused circuit.
