Inverter waveforms and relative efficiencies.

Max K

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I have recently replaced my 10yo quasi box with a new pure one because the latter runs our single cabin A/C unit without the rather annoying "ring" associated with fan motors running on modified sine wave inverters. The new unit, a Sterling 1600watt model runs the A/C just as if on shorepower.The Dutch A/C only uses 340watts on full output, which we never use but on 1/4 power, our preferred overnight setting in no facility small Greek ports, it provides just the right temperature for comfortable sleeping. I guess it is then only using 180watts. You might ask "What about a fully installed, water-cooled, generator run A/C system?" Spend a couple of nights next to one of those and you will soon know why. Our little air cooled split unit, made for RVs, is virtually silent in operation so doesn't disturb either us or the neighbours. If they are having sweatty, sleepless nights, they aren't going to thank you for the constant dribbling sounds and fumes of an overnight genny run.

Now here is the nub of the problem: Contrary to information posted here in 2008, "PSW" inverters are NOT more efficient than "MSW" ones, they are LESS so. However, I cannot, after much research , find out by what factor. I am about to replace the house batteries and will at the same time increase capacity by some 28%. Will this be enough? Rapid re-charging is not a problem. I just need a ballpark factor for DC consumption efficiency, MSW vs PSW.

Max.

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... Contrary to information posted here in 2008, "PSW" inverters are NOT more efficient than "MSW" ones, they are LESS so. However, I cannot, after much research , find out by what factor...
How could they be more efficient? A Modified Sine Wave is simply square wave with the "on" times reduced. A Pure Sine Wave inverter creates a pure sine wave from a square wave, so there will be some losses; I guess that √2 will come into it, so perhaps about 70%.
 
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