Posted 19 June 2016 - 03:58 PM
You do not need 150 amps. That is 1800 watts at 12 volts and would need about 3 bhp of engine power to drive it. If you unleashed 1800 watts continuous into any loudspeakers that would fit in a Mini, the voice coils would catch fire. If they did not, you would die, brain turned to jelly by excessive sound pressure level.
Audio does not require high continuous power, only on peaks, which the battery is well able to supply. A class B amplifier only draws as much power as is instantaneously required, and even if you really need 150 amps on peaks, which I seriously doubt, it will be running at no more than a few amps average.
Unless of course you are so completely conned by the spivs that frequent the supposed high end audio market and are using class A amplifiers which are extremely inefficient. But where will you put the heat? In any case the arguments about better linearity in a class A are entirely irrelevant to what is needed in an acoustically miserable little box with high levels of mechanical, road and wind noise.
I suggest that to avoid permanent hearing damage you need to rethink your need for power anyway.
Be aware that ALL "high end" and MOST in-car systems are just over-priced junk and lots of hype. (Actually the performance of supposed high-end systems is universally miserable, and they are sold to people with much more money than sense who are persuaded that it is smart to have a system where what they hear is nothing like the original.) You do not need stupid power or the spending of stupid money to obtain the best possible results.
And you really do not need 150 amps.