Originally Posted by seafox
why does a 115amp alternator
only put out 10 amps? Shouldn't it be called a 10 amp alternator
I only just got the email
to tell me about your posting
and I see that you already have lots of technical explanations which are very good.
In case you are still wondering, however, I will add my explanation - phrased so as to appeal to common sense - which is: when you buy a 115 hp car you will only get this much power at the motor
shaft when you are going at top speed uphill with the whole family
including the mother in law - lots of torque - with gas pedal down to the floor. Anything less will give you less power.
The equivalent of the car engine
speed is the alternator (boat motor) speed.
The equivalent of engine
torque is the demand the alternator seeks to meet, which is the reason for running your inverter
(coffee maker) while running your motor
to charge the batteries.
You need to understand that the alternator "sees" total demand and it may be sobering for our portuguese friend to realise that his alternator will be hard pressed to meet the 1200 W of his coffee maker. It may be comforting to know that at full output the alternator will be pushing out maybe 14 Volts instead of the nominal 12 Volts. So the coffee will be brewed before the alternator is cooked.
Hope this twopence worth of extra helps somebody to understand all the more technical stuff offered by our learned friends.