FuelMaster
[url=http://index.co.za/fuelmaster/product3.html]Fuel Master[/url] device to turn off alternator and a/c on your car for powre and mileage.
Shows alternator can draw 36.7 % of available powre at idle. (I didn't see mention of what engine/car it was based on). Down to about 6% at 2500 rpm.
Page is outdated but information might be worthwhile. I emailed LONG ago and never got a reply so I don't know if they are even in business. It is however reasonbly simple to use a hobbs switch and relays to turn off the alternator and a/c on most any vehicle. If I remember correctly the old Honda CRX HF actually turned off the alternator from the factory.
Groups:
Comments
FuelMaster
The SMEC and SBEC in chrysler vehicles is meant to turn off the field coils on the alternator when battery is fully charged and drain is low. AC runs on a clutch, so don't really see the gain there if you keep it switched off.
FuelMaster
I would think it'd be a better idea to increase the diameter of the wire going from your alternator to your battery, and from the battery to the fusebox. This will greatly reduce I*R losses and increase the efficiency of your charging system.
In my '86 Cougar, the alternator was putting out 15 volts (16v with the stereo, AC, and lights cranked up) but the battery was only seeing 13.8v. That means there is 2.5 volts lost between the alternator and battery. With a lot of current draw, 2.5v can multiply out to a lot of power loss. I've never maxed out my alternator, so I don't know exactly how much voltage that wire would lose. If it maxes out at 80 amps. If I'm losing five volts or more at full load, that adds up to 400 watts. With an inefficient alternator, that can be some pretty hefty power loss.