Solar panels have significantly advanced technically in the last decade or so, going from the panels that worked in series like old-time Christmas lights to those that work in parallel using panel-level electronics. That means the problem of shading one panel reducing the efficiency of all the panels has been eliminated. But what has emerged are two different types of panel-level electronics with two very different ways to power solar homes.
Solar panels produce DC power. Homes run on AC power. Which means that somewhere between the panels and the circuit-breaker box for the home, the power needs to be inverted from DC to AC. For this process, there are two schools of thought: invert the power at the solar panel, or create a central inverter that connects to the home’s power panel.
All batteries run on DC power. That means that only those homes that run optimizers will be directly battery-ready. Those who have Micro-Inverters will need a Rectifier to re-invert the AC power back to DC for storage, then back through a central inverter for use in the house. Since there is a drop in efficiency with every type of energy conversion, the fewer times the energy is converted, the more efficient the power system.
Another consideration when deciding between Optimizers and Micro-Inverters is the fact that Optimizers have a much greater reliability history in climates where there are significant temperature swings. Optimizers work at altitude and in the cold much more reliably than micro-inverters. Micro-inverters historically have had a twice-times failure rate in states like Colorado.*
When deciding which type of solar panel power inversion system is right for you – consider two things: the regular temperature swing from summer to winter the panels will experience and whether or not you’ll ever want a battery attached to your solar system.
If you have a wide temperature swing,
or ultimately will want a battery on your home’s solar panel system,
choose optimizers over micro-inverters.
* “The Enphase M190 microinverter admittedly had a very high failure rate. Some of our systems required 100% replacements with either the same model or upgrades” – Florida Solar Design Group
* “SolarEdge offers the most efficient solar system solution using power optimizers with a very low failure rate. They are significantly less expensive to install than Enphase micro-inverters and do not require expensive proprietary branch circuit cables. SolarEdge uses a web-based monitoring system that has proven to be simple, reliable and very comprehensive.” – Solar Electric Supply
* Enphase has been in financial difficulty for quite some time now, unfortunately. Due to this many financiers have pulled them from their approved equipment list.