Little inverter runs a fan better than my new 1100W??

[Sunking]

Voltage is within acceptable limits.

What size battery are you using to run the inverted. A 400 watt inverter needs roughly a 200 AH battery @ 12 volts. A 1100 watt inverter needs almost a 500 to 600 AH 12 volt battery. Try this little test. With the fan running, measure the battery voltage at the input of the inverter. I and do mean at the inverter input terminal, not the battery post. Then after you measure the input at the inverter, then measure the voltage on the battery post.

Lastly after you do the two above test, turn off the inverter and measure the battery voltage again.

You should find your issue.

[positiv4]

Hi all! New to the board here. My apologies if this has been discussed, but I couldn't find it here or on the www.

I have had a 400W Cobra inverter for a couple years and recently bought a 1000W of the same brand. I tested it with a desk fan and did not get full speed from the fan. I tried the fan with my 400W and got full speed. I figured the inverter defective (as modest inverters can occasionally be) and sent it back. I ordered an 1100W Power Bright and experienced the same exact thing - lower fan speed! This time I checked voltage with my kill-a-watt and I see that my 400W Cobra puts out ~120v while the 1100W PB puts out ~112v. I'm guessing the 1000W Cobra was putting out lower than 120v as well because the behavior seemed identical, but didn't yet have a kill-a-watt with which to test it. From what I can figure, voltage seems to be the only difference I can find which could explain a slower fan speed? But I am diving right into all this and learning as I go. The 1100W Power Bright seems to work well; it will kick my fridge compressor and run a larger TV (albeit with a little buzzing). I just don't get why the larger inverters that I tried won't run a simple fan as well as a little $25 inverter! I am not ready to invest in a PSW inverter yet.

Any thoughts, explanations or <$100 inverter recommendations appreciated!!