Matt, how are you connecting your scope to the current-monitoring shunts? Are you using normal probes on the 1x setting, or what?
Normal yes, set to 1X on the physical probe, yellow channel. Both channels are set DC bias. Common ground used for both probes.
On the higher current input side, the scope channel is set to 100X and connected across the 0.01 ohm shunt.
On the output side, the scope channel is set to 5X and connected across the 0.2 ohm shunt.
Only on the output voltage do I set the blue channel probe to 10X and set the scope channel to match.
For the testing I leave all shunts in-place, both input and output. I keep the system running stable and just move the probes (since I don't have a fancy four channel scope like yours). This to me is actually an advantage here because any scope or probe error should be identical between input and output measurements--i.e. if the channel is 2% low, it will be 2% low on both sides.
The load is a 75 watt 110 volt halogen spot light and when driven with a known 20 watt source has identical brightness--checked just for consistency.
Using a digital handheld meter, I can confirm the scope readings are all in the ballpark, with the scope readings likely being more accurate.
This is your ballgame Tinsel; if there is anything you are suspicious of, let me know and I'll recheck it--I get no paycheck for this gizmo either way. Being shy of the 130% efficiency anyway, might as well be sure the measuring is done right now, especially while I have everything still setup.
Oh, one thing I wanted to ask about, the phasing... I'm a little surprised the current and voltage are exactly in-phase. Typically a little offset is noticed. Is this because the device is actually running at full load or is there some other reason?
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