Durran Posted November 1, 2019 Share Posted November 1, 2019 Hi guys, I have a 5KVA Axpert inverter and on average, once a week, my load goes over and above the recommended inverter threshold due to various reasons such as the wife and kids putting a toaster on with microwave and airdryer. My installer mentioned that this should be avoided. My question is will this damage the inverter or does it just automatically switch to grid power? Gerrie 1 Quote Link to comment Share on other sites More sharing options...
Jaco De Jongh Posted November 1, 2019 Share Posted November 1, 2019 33 minutes ago, Durran said: My question is will this damage the inverter In my opinion, allowing this will eventually have a negative effect on the inverter.. Quote Link to comment Share on other sites More sharing options...
___ Posted November 1, 2019 Share Posted November 1, 2019 Most inverters can peak at twice their nominal rating for a second or two. So it really depends on how fast it goes back to the grid. It might be nothing to worry about at all. Quote Link to comment Share on other sites More sharing options...
Durran Posted November 1, 2019 Author Share Posted November 1, 2019 2 minutes ago, plonkster said: Most inverters can peak at twice their nominal rating for a second or two. So it really depends on how fast it goes back to the grid. It might be nothing to worry about at all. Great thanks, its literately for a couple seconds Quote Link to comment Share on other sites More sharing options...
___ Posted November 1, 2019 Share Posted November 1, 2019 2 minutes ago, Durran said: Great thanks, its literately for a couple seconds My answer of course reflects that it OUGHT to be okay. Jaco has more experience with Voltronic inverters so I am not disagreeing with his experience. He is not the only one who has told me over the years that it is in your interest not to stress them too much. Will it handle the peak? Yes. Is it designed to handle the peak? Yes. Does it stress the inverter more? Yes (that's true for other brands too). Will it shorten the life... again... yes (and also for other brands), so really, there is a design spec somewhere that's perhaps not published for all to see, a design spec that says it must be able to handle this X amount of times. As an analogy, circuit breakers can handle really high fault currents and safely disconnect them, but they have a specification of how many times it can do it. A cheap breaker can do 2000. An expensive breaker in excess of 10 000. So yeah... once a week probably fine. Quote Link to comment Share on other sites More sharing options...
Durran Posted November 1, 2019 Author Share Posted November 1, 2019 Great, thanks Plonkster Quote Link to comment Share on other sites More sharing options...
Crankshaft Posted November 1, 2019 Share Posted November 1, 2019 Even without those spikes, you are working that inverter HARD. ___ 1 Quote Link to comment Share on other sites More sharing options...
Durran Posted November 1, 2019 Author Share Posted November 1, 2019 25 minutes ago, Crankshaft said: Even without those spikes, you are working that inverter HARD. Thanks Crankshaft, would you recommend another inverter is put in series? Quote Link to comment Share on other sites More sharing options...
Crankshaft Posted November 1, 2019 Share Posted November 1, 2019 I'm no expert. I may be wrong, but operating a device at or near 100% capacity can't be good long term. Perhaps, someone with actual experience in this field, can make a suggestion. Quote Link to comment Share on other sites More sharing options...
Stanley Posted November 1, 2019 Share Posted November 1, 2019 2 minutes ago, Crankshaft said: operating a device at or near 100% capacity can't be good long term. Things will certainly fail quicker if you run them harder. This is true for electronic components too where heat for example will reduce the expected life. I would be most worried about the DC bus capacitors, as they usually have a life expectancy in the thousands of hours at a particular ripple current and temperature. Higher load on the inverter means higher temperature and higher ripple current in the DC bus caps. For cheap caps the life expectancy at the rated ripple current and temperature (probably 85°C for cheap caps) could be as low as 2000 hours with a doubling of life expectancy for each 10°C below the rated temperature, so temperature plays a huge role. Quote Link to comment Share on other sites More sharing options...
___ Posted November 1, 2019 Share Posted November 1, 2019 (edited) 1 hour ago, Stanley said: DC bus capacitors Indeed. Now go and watch Easily_Bored_Engineer's videos on what kind of capacitors you might expect in this product... To be fair... the manufacturer did update some of the components in later models, but only in terms of voltage (80V ito 63V). Life is still 2000 hours at 105 °C. Cooked electrolytic caps remain one of my bugbears. Edit: Rule of thumb is life doubles for every 10°C cooler, so those caps have a life of maybe 20 Phalaborwa summers Edited November 1, 2019 by plonkster Jaco De Jongh 1 Quote Link to comment Share on other sites More sharing options...
Jaco De Jongh Posted November 2, 2019 Share Posted November 2, 2019 21 hours ago, plonkster said: 20 Phalaborwa summers Leave me out of this....... ___ 1 Quote Link to comment Share on other sites More sharing options...
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