inline amp meter inaccuracy?

[stevehof]

I got this inline device called 'Kill a watt'. It plugs between your wall power and your power supply. It seems to be pretty accurate with my Meanwell 1000 watt PS as it shows about 13 amps out of the wall to drive my charger at 38 amps at 24v. However, when I tried it with my dual server power supply in series setup (where one of the PS power plugs has the ground stub cut off) it was not realistic. It was showing only 4.5 amps when the series PS were driving the same 38 amps at 24 volts out of the charger.

I had both server power supply power cords plugged into a power strip and the strip plugged into the Kill a Watt. What gives? Why is it so far off? The PS finished charging the four 4500 mah 6s in parallel in 40 minutes so I know it was putting out the asked for 38 amps as shown on the charger LCD display.

[TJinGuy]

check the power factor of each power supply on the kill-a-watt. that is one major factor, maybe accounting for 40% of the extra the meanwell is drawing. next up, the server units are more efficient, so they should loose less in the co.version than the meanwell but not by a lot, maybe 10%.max i would guess. next what do you mean by 38A? charge rate or actual ps output?

my guess is that the kill-a-watt is basically accurate.

[stevehof]

Originally Posted by TJinGuy

check the power factor of each power supply on the kill-a-watt. that is one major factor, maybe accounting for 40% of the extra the meanwell is drawing. next up, the server units are more efficient, so they should loose less in the co.version than the meanwell but not by a lot, maybe 10%.max i would guess. next what do you mean by 38A? charge rate or actual ps output?

my guess is that the kill-a-watt is basically accurate.

Thanks! Doing a charge with one power supply cord plugged directly into the Kill-a-Watt each individual PS goes up to 4.5 amps. I just plugged the alternate side into the power strip to power both sides up for the test charge. Beats me why they didn't show at least 9 amps when plugged into the Kill-a-Watt together using the power strip?

To answer your question I have the charger set to charge my four 6s Lipos at 38 amps so I'm assuming that's the current it is pushing through the 4 batteries?