How long will a 105Ah battery last?

Question

Rechargeable batteries

I want to buy a separate 105a / h battery in the car, so that I can autonomously use a laptop, printer and charger for phones. Accordingly through the inverter. So the question is, how long will this battery last if you plug it all into the network?

Answer 1

105 * 12 = 1260 Wh
recalculate for consumers

Answer 2

Purely speculative to find the answer to your question is not easy. Something is clear right away (for example, charging for the phone can immediately be excluded from consideration, due to the meager consumption). But the printer... It doesn't have a DC current to calculate the time from. In addition, printers are different. Let's say a laser has a kilowatt oven for fusing paint. It turns on periodically to maintain the temperature, and in view of the fact that it does not have a strict turn-on schedule, it will confuse all your calculations.
Yes, and with a laptop is not easier. When its battery is charging, the current is one, when it is charged, the current is different, smaller. The same thing depends on the brightness of the screen, on the clock frequency of the processor (with throttling, the current drops), and so on.
This I bring you to the idea that in order to answer your question, you will have to experiment - measure the real consumption currents in different load modes, and then somehow average them. Only then will you (and we) have data to answer.
Another option for such an experiment is to turn on your "on-board equipment" through such a counter:

or any other similar one. And operate for a week or two, powered by the mains, of course. After this period, it will become clear what energy they consume, and data will appear for calculating the time.