I have tried to test the efficiency of my inverter/charger, but what I am finding is that at best it is around 89% efficient, which according to spec should be up to around 94%. I am hoping someone can help clarify, or correct my findings, any input is appreciated...
My test setup, is using the MultiPlus Compact 24/2000. I have tested using the built-in battery monitor, as well as a BMV-712, both monitors show identical values.
I run the inverter with a set limit of 500W, which is a little less than 1/3 the maximum continuous output at 25* C. The BMV and MultiPlus both show an average discharge of 565W. Unless I am doing my math incorrectly, that means about 11% of the energy being drawn from the battery pack is being lost as heat by the MultiPlus. Again, unless I am mistaken, this would mean the efficient of the inverter would be considered as 89% efficient. This is the best value I can get. If I raise the inverter power the efficiency only goes down further.
Looking at this chart found here on page 3: https://www.victronenergy.com/upload/documents/Output-rating-operating-temperature-and-efficiency.pdf
The MultiPlus 24/3000 has an optimal efficiency when run at between 400W and 800W. 400W being 1/6 of 2400W, and 800W being 1/3 of 2400W.... I am running right in between this for my test, at 500W out of 1600W rated. Ambient temperature is around 22*C, and I never see the temperature sensor in my inverter hit 30*C.
Can anyone provide any insight as to why I am not seeing efficiencies at, or over 90% ever, at all? 65W of heat isn't that much from one unit at low load, but I have a 1x2 Split-Phase setup at the moment, with 3.2KWP, and and am looking at doubling that to 2x2 parallel/split-phase. I was really hoping to see a bit better efficiency with these inverters over my old AIMS one.
