Moderator &amp; Teksid Whore
Join Date: Jul 2002
Location: Laredo, Texas
yes it does.....the smaller pulley doesn't make the alternator put out more voltage really.........the voltage wont go up past the limits of the voltage regulator, no matter how fast you spin the alternator......if the alternator is under load, and the voltage is less than 14.7ish volts, it will go up because there is extra amperage capacity.....voltage drop is proportional to the quantity: instantaneous_amperage_draw/instantaneous_amperage available.........provide extra amperage availability, and there will be less voltage drop for a given power consumption.....the total instantaneous voltage drop across the alternator looks something like this:
voltage_drop= [unloaded_voltage - battery_voltage]*[instantaneous_amperage_draw/instantaneous_amperage_available].......if the instantaneous_amperage_draw is greater than the instantaneous_amperage_available, then the formula is not necessarily valid, since current will start to come from the battery sitting at ~12.6V....how much it drops beyond that depends on the current capacity of the battery and it's internal resistance......for continuous current draw situations, instantaneous values may be replaced with steady-state values
this is one reason it is not suggested to use the single-speed high-power Mark VIII fan with standard relay-type switching.....the instantaneous demand of 80+ amps of current at low cruising speeds will surely drain anything and everything the alternator has available, leading to future alternator damage.....yet, once the fan gets to speed, the charging system can keep up with a 30A-40A current draw, and the voltage drop wont be as much as when it initially kicked in
the closer and closer you are to the upper limits of the voltage regulator, the less the "increase" in voltage you will see in the charging system
Last edited by guitar maestro; 11-09-2005 at 01:11 AM.