This is the Electromaax performance curve for the 140A alternator. Electromaax uses a pulley ratio of 2.25:1 for this power curve. By knowing your ratio you can backwards engineer the performance off this chart.


Personally I would like to see Electromaax use alternator shaft RPM on their curves but they don't. Just know that their curves are based on a 2.25:1 pulley ratio.


Based on this performance curve we would need an engine RPM of 1675 to attain a 3000 alternator shaft RPM which puts us at near max performance for the alternator. So on this particular Volvo engine pushing much beyond 1675 RPM really gains you little in the way of added alternator performance.


If you run your engine at anchor for charging, or engine driven refrigeration, this is good information to know so you don't run the engine faster than is necessary and annoy everyone with unnecessary noise pollution. Sea Frost engine driven refrigeration systems attain max output by about 1500 RPM so this is a pretty close match up.


Even at an idle of just 1000 RPM this alternator can produce over 100A of current....