karlstewart avatar image

Pheonix 12/500 - does repeated overload stress unit to failure


I have a 12/500 Phoenix inverter. I run a small AC compressor fridge from it. It's nominally 70W, but I see around 660W when it initially turns on. Although 500VA continuous, it's 1000VA peak, and equates to 700W peak by my reckoning (not sure how they work that out). It would always start first time, although I would get that momentary hum when first starting. But after only a few weeks reliable running, I now get a permanent "overload" fault, even with no load connected.

I was told that the overload protection diodes may have failed through stress (a fail safe state). Does that seem fair?

For a time I was running the system from an old battery, and I can well imagine the voltage was very low at times (may have got a low voltage cut out fault on occasions). Would running the (momentarily) high load mean at low input voltage more current flowed, causing accelerated stress?

I'm now running from a Lithium pack which will be well charged at all times, and more than capable of supplying the power needed. But I'm worried that even if I have the inverter repaired, the same thing will happen again - repeated overload, even if momentary, will stress the inverter to failure.



Phoenix Inverter
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To clarify. It's the inverter that's 500VA continuous, 1000VA peak....etc

Did you get overload warnings everytime you started the fridge and what was the approximate average ambient air temperature? (output derates with higher temperatures)

1 Answer
kevgermany avatar image
kevgermany answered ·

First thing is to get the inverter checked/ fixed and a report on what failed with an explanation of what caused it.

How do you measure the startup current?

A high startup current is normal on fridges, microwaves and many other appliances. Normally it's for a very short period and if excessive will trip the breaker before you can measure it or it can cause damage. A battery switch to lithium from old lead acid will remove existing battery restrictions and allow a much bigger startup current.

If it looks as if the fridge has damaged the unit, there are inrush current limiters available for the ac side. But worth checking the fridge first.

But we're guessing until concrete evidence found.

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