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Inverter not charging a UPS


Haig
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I have a 4000 W inverter that powers the house mains during load shedding. Runs a few appliances and lights and internet no problem. However I also have an Eaton UPS that is meant to keep a desk top PS running and it is fine when the power goes down, it keeps running the PC from battery. However, when I have switched over to inverter power the UPS keeps beeping and stays on battery - for some reason it does not recognise the inverter power even though the fridge, routers and lights are happily running. Any ideas why this is happening? Many thanks for any insights...

 

 

 

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The Eaton UPS is not critical in my set up. All it does is prevent the need of shutting down the PC when I shut down the house power in order to switch over to the inverter power. It's a manual switch over, not automated...

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First guess. That inverter is not a true sine wave inverter but a modified sine wave inverter.

So the UPS does not like the modified sine wave it is receiving and thus stays on battery...

Do you have  a technical data sheet or spec sheet for that inverter ?

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Sorry, very short on technical specs. But pure sine wave is not mentioned in the product descriptions nor in the one page manual that came with it. 

 

Jry Power Inverter - 4000W The inverter is widely used in business travel, sailing trip, to provide AC 220V power for various electrical equipment, it is also widely used in some areas where the power supply is not normal and is very convenient for people working and living. Specification: Output Voltage: Ac 220V Output Frequency: 50Hz Input Voltage: 12V: Dc 10V-15V 24V: Dc 20V-30V Five Protection Functions: - With Over-Load Protection - High Voltage Protection - Low Voltage Protection - Over Temperature Protection - Output Short Circuit Protection Battery Drain With On Ac Load < 0.3A Peak Efficiency>90% Material: Magnesium Aluminum Alloy Shell, Imported Components. What's in the box 1x Power Inverter 1x Connection Cable - Black 1x Connection Cable - Red

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I think the fact that it does not mention true-sine wave means that your unit is a modified sine-wave design.

A sure way to check is to get one of your tech savvy friends with an oscilloscope to check the waveform on the output of the UPS (using a suitable step down transformer). Picture from https://www.nytimes.com/wirecutter/reviews/the-best-gear-for-your-road-trip/

The Best Gear for Your Road Trips | Reviews by Wirecutter

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What GreenMan said.  Either the voltage it is outputting is completely wrong, or the waveform is completely wrong.  Probably it is that it is "modified sine wave" AND voltage is not great.

Sadly cheap inverters that don't put out sine wave also generally don't have good quality control of their voltage.  And the wave form also typically gets worse and worse the more you load it.

Some electronics will run fine on it, others will not run at all, some may run but get hotter shortening their life span.

Mostly for non-sine wave you want to stick to universal power supply type electronics.  IE> things with power bricks and such.  Those types of converters immediately convert the incoming power to DC so they don't care what the input wave form looks like.

Things like fridges may run but the compressor will burn out or have dramatically reduced life.

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Oh wow. Thanks for the input. I wondered why there was such a massive difference in price for some makes over others. It must be the wave form. I will see about measuring it with an oscilloscope. Biggest worry is the fridge I guess, lights are fine and everything else has its own internal battery except the fibre router. So i need to check this. I appreciate the efforts in responding guys, many thanks.

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15 hours ago, Haig said:

Oh wow. Thanks for the input. I wondered why there was such a massive difference in price for some makes over others. It must be the wave form. I will see about measuring it with an oscilloscope. Biggest worry is the fridge I guess, lights are fine and everything else has its own internal battery except the fibre router. So i need to check this. I appreciate the efforts in responding guys, many thanks.

Did you wire this into your house?

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