How long could you gamble with a 12v battery?

The following example:

A man on a weekend trip alone only car and tent no hotel. Now he takes an additional 12v battery with 90Ah with the fully charged he connects there a voltage converter from 12v to 230v. Now he puts his Playstation 4 with 150W consumption in the game to the voltage converter to the playstation to a battery-powered screen. How long could he play until the battery is empty?

5 to 6 hours or until the tank of the car is empty (0,5L / h)

The performance data from the DC / AC converter is missing.

Such a change has no efficiency of 100%. Only when the value is known, the useful life can be calculated.

I have roughly calculated with 100% efficiency and 80% use of capacity.

The result is just over 5 hours.

You can set the efficiency of the voltage transformer at about 85%. Accordingly, it is roughly calculated so that 10 watts about an ampere correspond. That You can count on a current consumption of about 15 amps.

The problem is, you can never fully exploit the theoretical capacity of the battery. We go from 60%. That You have around 36 usable amp hours at 15 ampere current consumption. That makes about 2½ hours that's realistic.

I calculated the useful life a bit differently than the other users here.

I have the following values. Power consumption of the consumers 150 watts, the rated voltage of the battery with 12 volts and the capacity of 90 amp hours.

I first calculated the performance of the battery. So U * I = P, that makes 1080 w / h. Since I have assumed the use of capacity with 80%, I take nartürlich because the factor of 0.8 with pure, so 1080w / h * 0.8. And then I just divided it by the needed power of the consumer. So 864 w / h by 150th That makes 5.76 hours.

12V * 90Ah = 1080W / h

1080W / h * 0.8 = 854 w / h

854 W / h / 150 W = 5.76 h

Now I could also take an efficiency of 85%.

Then I would just have to add the efficiency factor 0.85.

854 W / h * 0.85 / 150W = 4,896 h

So then it would be almost 5 hours of use.

Everything calculated wrong! There's no usable 1080 W / h but only 270 W / h.
Why am I explaining you in a separate answer.

Real knowledge would be more helpful. Only does not like real knowledge is taught, it is often more secretive than explained.

Which battery type are we talking about here? Starter battery from the car, or a lead-gel battery? Strictly speaking, these 12 volts are only the mean value and defined as the operating voltage.

A car battery (lead-acid) is full only from 14.4 volts. From 13.8 V, it begins to gas, which is advantageous because Durschmischung. Durschmischung takes place while driving, by the way.

A lead-gel battery is full from 13.8 volts and should not get more voltage!
Now comes the most important thing, which is concealed!

Every type of battery of this type is empty as low as 11.4 volts! Everything under 11.4 means a heart attack for such batteries. How many heart attacks tolerate such a battery until he is dead?

In cars, it is more often and often charged and anyway only a few seconds used when starting the engine. That's why you do not have to worry about heart attack prevention there.

Now let us calculate. Auto battery full at 14.4, empty at 11.4!
That means there are only usable 3 volts. 3 V at 90 Ah gives only 270 watts and no 1080 watts! For lead gel it is 13.8 minus 11.4 equal to 2.4 usable volts.
Multiplied by 90 Ah, this results in only 216 usable watts!

So because of 1080 watts and so and so many hours, haha. It is only one fifth available, so much less time than most calculate.

Remember, in the car the battery has ideal conditions, you do not have to worry! For other applications already.