SolarEdge

SolarEdge optimiser

Lots of companies try to sell upgrades to SolarEdge. This is a system where the panels are each fitted with an ‘optimiser’ and the inverter is replaced.

What are the principal benefits of optimisers?

  • Increased yield (but not much) – optimisers are designed to tackle problems such as significant shading, mismatch of solar panels or other causes of yield loss. A shaded or otherwise impaired panel in a conventional solar panel system will have a knock-on effect on the other panels that it is connected to. A SolarEdge optimiser is a ‘buck-boost d.c. to d.c. converter’. It takes the output of the solar panel it’s connected to and adjusts the voltage and current to prevent any knock-on effect from that panel onto the others.
  • Monitoring – a side-benefit of optimisers is that they report their output and so the PV system can be monitored down to each individual panel.
  • Long warranties –  SolarEdge optimisers have a 25 year warranty as standard. The SolarEdge inverter has a 12 year warranty which can be increased to 20 or 25 years at additional cost.

Are there any downsides?

  • Reliability – it’s far from unknown for optimisers to fail. Companies sell the SolarEdge system as a more reliable alternative to the standard ‘string inverter’ setup. The reality is that a solar panel fault is extremely rare, but optimisers can and do go wrong. An honest installer will tell you that a string system is inherently more reliable as it contains fewer components.
  • Inflated claims of yield improvements – most PV system owners would not see a significant increase in yield following the installation of SolarEdge equipment. Lightly shaded or unshaded systems may increase their annual output by 2% to 5%.
  • Cost – An upgrade to SolarEdge comes at significant cost, even when you’re dealing with a fair priced installer. The more panels you have, the more optimisers you would require, and a 16-panel system may cost £3000 to upgrade to SolarEdge. The companies shamed on this website will charge much more than this.

Summary

SolarEdge equipment may be worth having depending on your budget and whether you will remain fascinated with the monitoring. However, there are various points to consider…

  • You must consider what will happen if an optimiser fails, particularly if your installer is not local to you or if they cease trading. Will you end up paying someone else to replace it?
  • SolarEdge optimisers are proprietary, what if SolarEdge themselves cease trading? Long warranties are no good when the company doesn’t exist any more.
  • Notwithstanding the above point about company stability, other inverter manufacturers offer 20 year warranties on their products too.