If you google “best solar inverter 2019” list, you’ll find a lot of recommendations that we believe absolutely do not make sense to install on your home. There are only four inverters (including DC optimisers and microinverters) that we recommend based on our extensive experience installing solar.
We will guide you through the nonsense and help you make sense of the only solar inverter solutions that we believe are worth considering.
String Inverters, Microinverters or Optimisers?
Many so called solar experts will tell you untill the cows come home that the best way to do solar is use microinverters. A microinverter is a piece of power electronics that converts DC power to AC power behind the panel. This piece of equipment is required on every single panel, but also requires a ‘brains’ unit down next to your switchboard (much like a string inverter). Now don’t get me wrong, micro’s can have their place (that DC optimisers do better in my opinoin), but it’s usually limited to extensive shading issues over your roof.
If you want quality and bang for your buck, you should keep it simple and go for a string inverter (Sungrow, Fronius or Delta).
Serviceability Outside The Warranty Period
When (and it is a case of when) microinverters fail, someone needs to get on the roof and lift a panel to replace the product. Brackets can seize and all hell can break loose, especially after a long period of time. Keep it simple and stick with a string inverter unless you absolutely have no other choice.
Getting Maximum ‘Peak’ Production
Back in the day we were limited by only being able to put a 5kW inverter on a single phase residence. The rules have changed and solar has advanced to the point where adding 10kW worth of inverter with export limiting is now the new norm.
We used to be able to ‘oversize’ panels relative to the inverter. For example, a 5kW inverter could have 6.6kW worth of panels installed (133% generation capacity). The advantage of this is that it’s rare for a system to peak at 5kW, and the extra 1.6kW worth of panels worked in our favour to increase the production of energy in times of the day when people could actually use it.
Microinverters are different. There is one micro per panel. Each panel is limited by the capacity of each micro inverter. Therefore, we must install a micro that has the same output as the panel, otherwise we get clipping and loose too much power. Therefore we can’t oversize as much as a typical string system and lose out on extra efficiency.
Getting Locked Into One Brand
Its best to go for an inverter that is interchangeable. That means if one of the major players goes out of business, you have the option to go with another top end string inverter. Microinverters cannot do this as the micros and the brains of the unit must all be the same brand. This presents problems if a brand goes out of business and your stuck with a failure of some sort.
Tigo’s solve this problem somewhat as they are a DC optimiser and thus can be retrofitted onto a string inverter system on a panel by panel basis. If Tigo goes out of business, you could find another DC optimiser and switch it out with that, like Huawei for example.
So Whats The Best String Solar Inverter?
Many people will say out of the gate that Fronius is the best inverter. This is because Fronius has such an excellent history as a company and has been in the game such a long time. Combine this with the fact it’s made in Austria and there’s a lot to like about their inverters. The flexibility of design, ease of use and slick aesthetic appeal means it’s a crowd favourite here in Australia.
On par with Fronius would be the Delta inverter. Recently Delta won an award for best commercial inverter of the year. This is quite a prestigious award and shows that Delta has their stuff together. Admittedly, Delta has a better monitoring solution when compared with Fronius and their tech support is close to the ground. The same can’t be said for Fronius, where tech support varies on a day to day basis.
The best budget end solar inverter has got to be the Sungrow. Sungrow is a Chinese company and one of the biggest inverter manufacturers in the world.