How Big a Gen to Run a Converter? Some Info.
EDIT: some of my earlier posts in this thread have the wrong idea. As more info came in later, things got less confusing--sort of! :) --------------------- Another look at this topic. It is n...
Forum Discussion
I'll add to the brain puzzler
I just took my kill a watt
And my ac/dc Clamp on ampmeter and my line splitter for ac testing and made some
Measurements
Output 64.7 DC amps at 14.2v measured
Kill a watt input reading's
122.4vac 59.9hz 917w
But
10.95amps 1338va PF 0.68
But the ac clamp meter reads 7.97 ac amps
3amps less than what the kill a watt says
64.7*14.2=918.74w almost a match for the what the kill a watt claims is input watts strange huh
122.4*7.97=975.52w that would be heat ? Conversion loss of 57 watts
But
122.4*10.95=1340.28 real close to the displayed 1338va
So here my guess va reading is peak power reading
Watts is the real apparent consumed power
The 7.97 amps reading of the clamp on amp meter is true RMS value amps consumed
And true power consumed is the 975w
917/0.68=1348.52 ... close to 1338va reading
7.97/0.68=11.72 amps?
1338*0.68=909.84 watts?
Conclusion
The kill a watt is not perfect, its math works on some sort of curve
PF is the relationship between watts and va
Not a measure of power loss
VA versus volts kinda like dynamic force relates to static force
For our concern in this case 'charging'
We are interested only in power consumed versus charging watts
Pure efficiency aka power loss
With the KAW
917w/0.68pf=1348.52 va? Watts?
And
122.4v*10.95a=1340.28
Am I consuming 1340w to create 917 input watts to create 918 ouputwatts
I'm running in circles
I know the PD does Not feel 400watts hot
Heat wise the output is very low
I'm inclined to believe the clamp on meter
7.97 amps real use aka 975w input 918w output
975w/1340=0.72xxxx pf ? , again it seems of is a relationship number not a power conversion use loss
And 10.95*0.72=7.884 amps.. The amp meter displayed 7.97 amps
Again real is about 8 amps not 10.95
At these numbers a 1000w generator would be right on the edge and could not handle the start surge but might carry the constant 8 amp load
So it won't start a 64 amp load but might carry a 40+ amp charge
40*14.2=568w/0.72pf-ef=788.88w/122v=6.46amps ac
This is all clear as mud, heh
I just took my kill a watt
And my ac/dc Clamp on ampmeter and my line splitter for ac testing and made some
Measurements
Output 64.7 DC amps at 14.2v measured
Kill a watt input reading's
122.4vac 59.9hz 917w
But
10.95amps 1338va PF 0.68
But the ac clamp meter reads 7.97 ac amps
3amps less than what the kill a watt says
64.7*14.2=918.74w almost a match for the what the kill a watt claims is input watts strange huh
122.4*7.97=975.52w that would be heat ? Conversion loss of 57 watts
But
122.4*10.95=1340.28 real close to the displayed 1338va
So here my guess va reading is peak power reading
Watts is the real apparent consumed power
The 7.97 amps reading of the clamp on amp meter is true RMS value amps consumed
And true power consumed is the 975w
917/0.68=1348.52 ... close to 1338va reading
7.97/0.68=11.72 amps?
1338*0.68=909.84 watts?
Conclusion
The kill a watt is not perfect, its math works on some sort of curve
PF is the relationship between watts and va
Not a measure of power loss
VA versus volts kinda like dynamic force relates to static force
For our concern in this case 'charging'
We are interested only in power consumed versus charging watts
Pure efficiency aka power loss
With the KAW
917w/0.68pf=1348.52 va? Watts?
And
122.4v*10.95a=1340.28
Am I consuming 1340w to create 917 input watts to create 918 ouputwatts
I'm running in circles
I know the PD does Not feel 400watts hot
Heat wise the output is very low
I'm inclined to believe the clamp on meter
7.97 amps real use aka 975w input 918w output
975w/1340=0.72xxxx pf ? , again it seems of is a relationship number not a power conversion use loss
And 10.95*0.72=7.884 amps.. The amp meter displayed 7.97 amps
Again real is about 8 amps not 10.95
At these numbers a 1000w generator would be right on the edge and could not handle the start surge but might carry the constant 8 amp load
So it won't start a 64 amp load but might carry a 40+ amp charge
40*14.2=568w/0.72pf-ef=788.88w/122v=6.46amps ac
This is all clear as mud, heh
