It is that formula I used (I termed it "watts acceptance") to formulate a curve for the 150 amp charger. X amps times desired voltage set point in agreement with generator voltage and Hz determines the actual not theoretical ability of the generator. X amps times volts = va
There is a peak after which generator Hz or AC va starts to slump.
In short battery charge acceptance in va versus generator va available. Difference can be expressed as pf GROSS Power Factor. Energy Efficiency.
Generator harmonic waveform distortion under high loading % is responsible for a lot of discrepancies between apparent power available and actual power delivered by a generator. A high percentage of agreement between generator and charger is necessary in order to obtain the optimum.
This is why I opted for an extremely expensive stator winding in my Kubota / Kato. Simply put, the 15 pounds +, of extra copper allows the KATO to respond like a 15Kw instead of a 12.5Kw this means an ability to develop more power with the same horsepower with an inductive load.
This is not possible never mind feasible with a lightweight portable unit.
But it DOES explain WHY there is an apparent discrepancy in efficiency.
