SMA Sunny Boy Inverter Cut Out Stuff
This is a brief post just to inform anyone who does the appropriate websearch about something that might happen to their solar inverter.
We have a 3kW system on a north-facing roof. The panels have been quite reliable, although the financial incentives are so lousy in NSW (Australia) these days that installing them at all is not a great benefit if money is the sole criteria. But, you know, you try to do the right thing, and as we know no good deed goes unpunished…
We have an SMA Sunny Boy inverter, which does not look like a tetrahedral ice block with nostalgic resonances, nor does it look like a great Aussie rock band; in fact, I think they are designed in Europe and assembled in the US, probably from Chinese parts, though that is a guess…who knows?
So on the front is a display panel, and it lists a bunch of stuff, including the voltage from the grid that the inverter has to match when putting power back into the electricity grid. The voltage reading on the left is that from the panels, and alternates between the two inputs the system can use, though we are only using one; hence below it says zero since it is showing numbers for the second, unused input. On the right it shows the current the system is putting into the grid, and this number alternates with the grid voltage that it has to match to do so. Below I circle where the AC current and voltage numbers show up.
Now, our system was cutting out periodically, and it was happening when the grid voltage got too high; the screen read ‘grid fault’ and we got no power out of the solar. It should cut out if the grid goes above 265V, which is quite a way above the nominal 240V we expect. This gives error 103 — ‘grid voltage high (slow)’ which just means the grid voltage was getting too high and staying there too long. This causes the inverter to disconnect from the grid, and in these systems that mean no solar power. Of course, this happened on a series of nice clear days when we would have generated heaps of power… this was identified as the problem with some helpful hints from SMA’s Australian operations, who answered emails promptly and provided very useful advice.
The Explanation & Obvious Solution
So the solution was just to ring up the power company and have the transformer on our power pole adjusted. Essential energy did that within a couple of hours of our call, which was nice. It turned out that upstream upgrades had resulted in higher line voltages at our transformer, which translated to higher voltages at our meter and too much voltage in general.
The main conclusion is (assuming you’re in Australia, but I guess analogous advice would apply elsewhere) whatever inverter you buy, make sure they have an Australian operation which is helpful and on the ball. Our installer went into liquidation earlier in the year and could not offer any advice or help, but because SMA have an Australian operation familiar with Australian practices and systems and power companies, they were able to offer us support. Further, even though the installer was bankrupt, SMA Australia still honour the warranty on the inverter, and said if we got an authorised installer out to look at it and it did turn out to be an inverter fault, they would cover costs (can’t recall if it was all costs, to be honest… we are out of town and might have had to pay some travel, for example…). I’m not advertising SMA especially, but I would say that if you want to go solar, ring up the distributors of the components as well as dealing with the installer, to help you decide on which hardware to go with. If there is no local distributor, be wary!