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Powerpack/Inverter troubleshooting
#1
I have one of those store bought lithium generator (ExpertPower 288+) that is supposed to be 288Wh, pure sine wave, 500w continuous, 1000w surge rated.  I have always used it for small loads like charging a laptop, led lights etc.  Someone asked to use it to run a substantial desktop computer.  However, when I plug in a desktop (I've tried two) it won't boot.  It tries for like one second and then loses power.  I put a power monitor on it and I see the computer drawing stand by power but it basically resets as soon as I turn on the computer.  On one computer the power supply made a sort of clicking sound until I unplugged it.  I tried running other devices (heating pad, battery charger etc.  It was steadily running 200+watts which is higher then what the computer was drawing (I measured it on house power). Any thoughts on what it may be?  What tests can I do?  (I started this thread here because I'm assuming it is related to the built in inverter)
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#2
Sounds like the 'ExpertPower' just can't provide enough power for the desktop computer.   It may say it can do 500w but maybe it can only do 300w or 400w in reality and that might not be enough.    

To debug this - you could get a killowatt meter ( https://www.amazon.com/P3-P4400-Electric...995&sr=8-5 )and see what the computer uses when plugged into the wall.   Then do some tests on the ExpertPower to see what it can 'actually' support...   use the killowatt meter to a power strip and then plug in a series of items until you max it out and see where it fails.    

Then compare the 2 numbers Smile
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#3
(06-27-2020, 11:55 PM)OffGridInTheCity Wrote: Sounds like the 'ExpertPower' just can't provide enough power for the desktop computer.   It may say it can do 500w but maybe it can only do 300w or 400w in reality and that might not be enough.    

To debug this - you could get a killowatt meter ( https://www.amazon.com/P3-P4400-Electric...995&sr=8-5 )and see what the computer uses when plugged into the wall.   Then do some tests on the ExpertPower to see what it can 'actually' support...   use the killowatt meter to a power strip and then plug in a series of items until you max it out and see where it fails.    

Then compare the 2 numbers Smile
I'm sorry I wasn't clear, I did that already.  I called it a power monitor, what is the commonly used name for these devices?  I've always thought of the kilowatt as a specific brand, but, is it also used as a generic description?  I ran a 350w load using other devices and it handled it no problem.  I ran the full computer system and a tv on the power monitor for over 2 hours and it never went above 230w.
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#4
Sorry my bad - I do see that you did power readings.  OK, then the only thing I can think next is that its not really a 'pure sine wave' and the computer doesn't like what the inverter is putting out.    Do you have any way to check the output waveform?   

And forgive me to ask this since its an international forum and different countries have different power and I can't think of anything else - is the inverter putting out the same voltage (120/240) that the computer expects?
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#5
There's two reasons that inverter might not like the computer:
- at switch-on there's usually a pulse of power drawn triggering overload (hence the clicking noise - it's retrying repeatedly)
- a computer's PSU typically draws power not in a smooth sine wave but in sharp pulses at the peaks of the waveform & the inverter may see this as overload.

The power meter you're using will be measuring the average current not the peaks.
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#6
Along with Redpacket, there are also large caps usually in a psu to help smooth power for the sensitive components. So it's possible there could be a high inrush current as well.

The best way to test how much the computer *actually* uses is to connect it to mains power and use a combination of the watt-meter and an inrush current meter (this is clamped only on the hot leg of the mains line). That way you can narrow down the issue.

Also, you state that you can a 350W load for hours. But, have you tried a 500W load? Even a 700+W starting/surge load? Maybe the inverter "really" isn't a 1000W surge *or* it's faulty and you just hadn't noticed it until now because you never pushed it that hard.
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#7
The surge is most likely the problem. Common on cheap Gear
Especially when using inverted psus Smile
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