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Old 09-06-2011, 01:30 PM   #82
Master Po
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Join Date: Aug 2010
Location: USA
Posts: 382
My Ride: E46 no more
Originally Posted by celluloidheros View Post
Anyway, in sleep mode, when I pull fuse 41, the bottom fuse 41 receptacle is always hot and has 12.5 volts (same as the battery voltage at the terminals in the trunk). the top has 10.5 volts after pulling the fuse and slowly drains down to less than 1 volt over time. Fuse 41 will spark when you plug it in, so mimnimize then number of times you unplug/plug the fuse, disconnect battery when possible.
that's exactly what a capacitor is supposed to do: it stores energy while the voltage is available, and put that energy back in the circuit when the voltage drops (as in you removing the fuse). In essence, it's working like a very small battery. The bigger the capacitor, the longer it will be able to hold the voltage. That is why you see those huge canisters (the size of two beer cans stacked on top of each other) used by high powered audio installers. When a particular low frequency note demands more power than the battery can supply, the capacitors pitch in with their stored energy and the voltage holds constant instead of dropping and distorting all other frequencies.

Last edited by Master Po; 09-06-2011 at 01:32 PM.
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