Will a stereo amplifier with a power supply range of 12V to 25V DC run off a 12V car battery?
The description mentions TPA3116D2 which is a D-class power amplifier that can work from 4.5V up to 26V, so a 12V car battery (that actually walks between 10V and 15V depending on its state of charge and the presence of a charger) lies well within this range.
The rated power (50W at 4 ohm) is achieved at 21V power input voltage. The less voltage, the less maximal power. The datasheet tells something like 25W at 14.4V (the voltage in a car with engine running).
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The rest of the device is the bluetooth circuit which itself runs at either 5.0V, 3.3V or 1.8V, derived internally from whatever power supply is available.
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I think you can safely run it off a 12V car battery if you are OK with somewhat reduced maximum output power. There is a nice graph in the TPA3116D2 datasheet.