Calculating Surplus Wattage

[GLantern]

Wow thanks so much for all this info!  Talk about answering everything!

[Keld]

This is a little closer estimate. The load column is what could be drawn, the real column is a realistic draw during normal operation.

                               Load        Real
Headlight Main Beam   60           55
Side Light                    5              5
Number Plate              5              5
Rear Lamp                  5              5
Brake Lamp               21              0
Indicators (2)             20              0
Instrument Panel        2                2
Fuel Pump                60              60
ECU                         48              48
Fans                        60                0
Horn                        60                0
Total                      346             180

And then you have to add x watt for charging the battery

[Capo]

And then you have to add x watt for charging the battery

And that would be what?
Read above, when the load exceeds the capacity of the alternator, the battery makes up the shortfall. When the load is less than the output of the alternator, the surplus is available for charging the battery (if the regulator requires it).

[Keld]

Yes but if battery voltage is low it vill need some of the current from the alternator ,  at the same time as your other loads. 

[Capo]

Loads are satisfied first, the regulator will charge at a rate according to the surplus capacity of the alternator.

[Howie]

Yes but if battery voltage is low it vill need some of the current from the alternator ,  at the same time as your other loads. 

An alternator with a wound rotorneeds current to make current.  Your Duc has a permanent magnet rotor.

[Keld]

Loads are satisfied first, the regulator will charge at a rate according to the surplus capacity of the alternator.

According to your list there will be a surplus, so the battery will will charge at the same time as your other loads draw current.

The rectifier/regulator dont "see" any difference between loads  and charging needs. It just try to keep the voltage att same level.

[Keld]

An alternator with a wound rotorneeds current to make current.  Your Duc has a permanent magnet rotor.

I  know the difference, But I did not say that the alternator needed current , I said the Battery 

[Capo]

According to your list there will be a surplus, so the battery will will charge at the same time as your other loads draw current.

The rectifier/regulator dont "see" any difference between loads  and charging needs. It just try to keep the voltage att same level.

At last you got it.

I never said that the regulator monitors currrent, it looks at the battery voltage and charges at a rate according to the power available from the alternator.