Originally Posted by
Mrmiata
Now is your chance to preach.. since you don't have "charge" ports and separate "device" ports just how does the battery "filter" anything? The same wire feeding your battery is attached to the whole circuit of the car. Help stabilize the current I could buy... but filter?
"Stabilize" and "filter" are really the same thing here.
In effect, the great current-sinking capacity of that huge battery acts as a filter capacitor.
If you were to take a 'scope and put it on the positive battery terminal, you'd see a fairly 'quiet' dc voltage of about 14 volts.
Now, with the engine running (DO NOT REALLY DO THIS!) undo the battery cable from the battery - taking the battery out of the circuit. You will see a HORRIBLE pattern on the 'scope. This is because the car's alternator DOES NOT produce clean DC voltage, but the summed output of either 3 or 6 phases of AC that has been rectified. The voltage will be a fully rectified sine wave, NOT DC! (Ok, it's actually fully rectified multiphase AC, so it won't go all the way to zero volts between "peaks" because the 3 peaks happen at different times.)
It is the battery that filters this.
I am at work and must go now, if I can find pictures or drawings of this, and I know they exist, I will post them.