{"id":71127,"date":"2023-03-10T06:13:55","date_gmt":"2023-03-09T19:43:55","guid":{"rendered":"https:\/\/www.solarquotes.com.au\/blog\/?p=71127"},"modified":"2023-03-10T06:13:55","modified_gmt":"2023-03-09T19:43:55","slug":"solar-inverter-installer-wishlist","status":"publish","type":"post","link":"https:\/\/www.solarquotes.com.au\/blog\/solar-inverter-installer-wishlist\/","title":{"rendered":"What Solar Installers Want From A Solar Inverter"},"content":{"rendered":"

\"What<\/h3>\n

I asked fellow installers what they wanted from a solar inverter, and they answered decisively:<\/p>\n

More current, please.<\/strong><\/p>\n

We need inverter DC inputs that handle more amps. That’s the biggest single wish expressed in my latest informal poll. However, unlike my other recent poll on what installers want from solar panels<\/a>, many more options and opinions were expressed.<\/p>\n

Forty-two votes, or 15% of the respondents, nominated what we already know has become a problem with solar power of late. The latest generation of panels have grown into monsters, with current output in the 10 to 15 amp range. Sadly, inverter manufacturers haven’t kept up with the rising currents.<\/p>\n

A Potted History Of Solar Panel Current<\/h2>\n

In and of itself, more current isn’t a problem. But the failure of inverter manufacturers to follow up with higher current capabilities is now translating into electrical design problems for installers on the front line.<\/p>\n

This isn’t an entirely new problem, I installed systems around 2010 with Evergreen brand modules, which were half the voltage and twice the current of everything else.\u00a0At 22 volts open circuit, they were excellent for building what were at the time “big” 5kW systems<\/a> in one string<\/em>, (amazing!) – but terrible for “normal” 2kW arrays because most inverters topped out at 10amps input. The SMA SunnyBoy 1700 was the only inverter capable of 12 amps and a low enough voltage to start in the morning.<\/p>\n

As system sizes grew, panels changed electrical characteristics and physical size. In round figures, the average module was 200 Watts, 5 amps, 45 (open circuit) and 36 (nominal) volts. They changed to 250 Watts, but at this point, they also dropped to around 38 (open circuit) and 31 (nominal) volts, while current increased to 8 amps.<\/p>\n

Split Cell Panels Push Currents Even Higher<\/h3>\n

When so-called split cells or “half cut” solar panels<\/a> were introduced, the wiring connections moved from one end to the middle of the panel because you now had 2 panels under the same sheet of glass. With twice as many cells, the voltage could be maintained, and the current doubled. What really improved was that shading a cell would only hobble 1\/6th of the panel.<\/p>\n

The point still remains though that there are two classes of panel. The 45VOC \/ 5 amp 72-cell modules have grown to 50VOC \/ 10 amp and 144 cells; which I’ll refer to as a high voltage – low current. The more problematic module is the 60 or 120 cell variant because they end up being 39VOC \/ 13amps. So with 30% more current, these units are too much for many inverters once you apply the Australian rules for a 1.25 multiplier.<\/a><\/p>\n

And despite being helpful for the silly Australian 600V system ceiling, the lower voltage solar panel begins to be its own pain in the backside because you only need 16 panels for a 6.6kW system<\/a>. Two strings of eight panels don’t make for a very high input voltage, which in turn makes the inverter inefficient and to make matters worse, the low voltage and inability to parallel on some inverters make the electrical design even less flexible if you have small roof spaces or multiple orientations.<\/p>\n

Technical Support Matters<\/h2>\n

This is a story about solar inverters<\/a> isn’t it? Except the next most popular point from the installer community wasn’t about the hardware, it was about support from inverter makers. In fact, combined, this is the most important point.<\/p>\n