Fannying about ...

[Pamela]

Limey, the short answer to your question is yes.

The long answer is, well, long. And technical. Your electrician mate can explain more fully. In essence, you have an AC/DC inverter in your power supply. It is inefficient and will drain your battery even if nothing is plugged in. But you can do what you are planning.

My advice to you is to buy a small (100-150 watt) car inverter and plug it into your 12vdc outlet. You should have one someplace. Then unplug it after use.

In my case, I replaced the two deep cycle batteries I had with four heavy duty truck deep cycle batteries to give me more useful power and will be adding a solar charger to the roof to keep them topped up. I will replace the OEM inverter with a more efficient aftermarket one at that time.

Manufacturers use the cheapest stuff they can find to save weight and reduce costs. This increases their profit but at the cost of end user perceived quality. I have also replaced all the plumbing with quality fixtures after a bad winter freeze ruptured the plastic faucets.