Curious question about Watt hours?

I picked up 2 small Vornado ‘fans’ recently. Im very happy with the fans so far. They older models so discounted.

Today decided to run one in kitchen using the EB3A and one in living room on Delta Mini. I was surrised to see diffence in output watts and the same fan (I did connect the same fan to the EB3A just to rule out fan anomaly ).

On the EB3A the 3 speed fan used 27w, 65w & 89w (fr memory) but on the delta mini the same fan draws 22w, 38w & 67w.

Obviously the inverters r different but still doesnt explain why the EB3A is reporting so much more watts used at each speed. My brain is tired so maybe im missing an obvious answer.

Curious if anyone has had a scenario where u have run a device on different power station and see different watts used, how do you explain it? Cant be rounding cause that significant for rounding.

I bought the fan and thought it was a very efficient AC device so I got a 2nd one (65-70w on high i thot good).

Ill try to post pics later.

The best way to test the fans is with a kill-a-watt meter, then you will see the same watts from both units. Please tell us your output with the kill-a-watt.

@roxie60 I can think of two possible reasons:

  1. The AC output voltage is lower on the Delta Mini (although this would only account for about 10% diff in watts, not the 20-30% you observed)
  2. The method by which each power station is measuring watts is different and could be measuring apparent (Volt-Ampere) or real (Watts) power.

Dividing active by apparent power gives you your power factor. A Kill-a-watt meter will tell you all three of these metrics.

I did a small test on my own EB3A which outputs 121V and my 3-Speed Honeywell HT-900 fan connected to AC with nothing else connected:

Fan Speed Kill-a-watt
Power Factor
Watts (with Kill-a-watt)
Watts (without Kill-a-watt)
1 24 39 0.6 35 39
2 28 46 0.6 42 46
3 34 58 0.6 53 58

So some conclusions based solely on this data:

  1. The EB3A is measuring apparent power consumption using Volt-Amperes (VA) and not real power using Watts but displaying it as “Watts”
  2. The Kill-a-watt uses 7 VA of apparent power but 0 real power in watts

I did the same test on my second power station, an Energizer PPS320 which generates 114V output:

Speed Kill-a-watt
Power Factor
PPS320 Watts
(with Kill-a-watt)
PPS320 Watts
(without Kill-a-watt)
1 22 34 0.6 20 20
2 25 40 0.6 24 24
3 30 50 0.6 28 28

The PPS320 is measuring real power consumption using watts and displaying it as “Watts” as well. As such, the displayed output watts it the same with and without the Kill-a-watt plugged in for the tests.

So different manufacturers will choose to display VA or real Watts and Bluetti is choosing VA for the EB3A and from your test data the Delta Mini is choosing real Watts like my PPS320 which is why it displays lower power usage.

I wonder which one is actually the more accurate metric to estimate runtime, anyone know? If I were to make an educated guess then I would go with VA.


I think you are on to something there. I’ll test again w/ my kil-o-watt meter. Thx for the work. If the EB3A is not displaying actual watts that means more work and have to determine if the per watt price point is resulting in distorted expectation and price point. Sparked my interest. Thx for the replies.