The speaker has an RMS amplifier output of 210 watts, which is what it delivers in the long term. Whether mains or battery. The power amplifier always requires the same power.
And 210 watts RMS is quite a lot, which is why the speaker is often used by DJs.
The louder the speaker is turned up, the greater the load on the battery, so it can happen that the battery is empty after 4 hours. In terms of sound, the speaker always sounds great, but normally you should never drive at 100% power, always stay below 80%, otherwise you would need a larger speaker or several.