theoldwizard1 wrote:
Define "heavy" ? If the typical vehicle load, at idle, is 40 A and you have an alternator capable of 100A, the alternator will just call for more engine speed. (Alternator don't reach max capacity until about 2000 engine RPM.)
Most trailer tow packages include a heavy duty alternator. If not, that is a good upgrade.
Alternator IS NOT going to "call" for more "engine speed", alternator is extremely tiny "load", so small it is insignificant..
Not sure how much HP you believe an alternator is going to need but 220A 12V alternator is 2,640 watts..
General rule is 746W is equivalent to 1 HP..
Using the general rule a 220A 12V alternator is going to need a max of 3.5 HP from an engine capable of 300+ HP which is about 1% of that engine..
If a 300HP engine cannot stand a 3.5 HP (1%) alternator load without the need to alter the RPM it is time to scrap that engine design, it is junk..
I think your assumptions that the body control or engine control is going to automatically "boost" the idle JUST FOR THE ALTERNATOR is wrong.
Manufacturers do not even do that for the A/C compressor (RPMs DO drop when the A/C compressor turns on at idle, typically a 50 RPM drop in idle speed).
Now if you are talking an "Ambulance or Emergency" prepped vehicle, that IS a different beast, those vehicles ARE modified and certified for those types of use where they may have special critical power needs..
