Optimizers and Microinverters are similar in that they are installed at the module level. Microinverters perform DC to AC conversion, where as optimizers are considered DC to DC converters.
They simply optimize the current and the inverter then converts from DC to AC.
A solar system that runs on microinverters and a solar system that runs on a central string inverter with optimizers will, when it is working properly, have the same overall effect. Each panel will be able to make maximum power regardless of what its neighbors are doing, as long as the minimum system voltage is met (the "edge" inverters work at exactly 350 volts so at least 6 panels need to be making a good amount of power before it will turn on... microinverters will make power when only one panel is making power, while the average central inverter can turn on with just 50 volts, which can happen even when all the panels are in shade)
Fans of microinverters will say that the most common thing to fail is a central inverter, and that central inverters can't handle shade anywhere near as well as microinverters. Central inverter fans will say that putting complex power electronics under the panel where it gets ridiculously hot (electronics don't like heat) is asking for things to break. Also requires lifting up the entire array to replace broken parts, so repairs are expensive.
Using a central inverter with optimizers would seem like the worst of both worlds... a central inverter that could fail *and* complex electronics under each panel. But, there is more to the picture. The "edge" optimizer company does have somewhat common optimizer and central inverter failures. The detailed monitoring system ends up being best used to know when an optimizer has died. Take a look at some of the MC Electrical videos on youtube, he talks about how many microinverters he's needed to replace, and how many of the "edge" company's optimizers have gone bad. And with the exception of a specific brand of panel that was going over the maximum voltage spec on the Tigos, how many Tigo optimizers has he needed to replace, in thousands of deployments? Zero.
Hi Ben,Both optimizers and microinverters are means of achieving maximum power point tracking on the module level, and they can both be used to mitigate production loss (for example: due to shading or mismatched panels). The big difference is microinverters convert DC energy into AC energy right from behind panel where they are mounted, and optimizers are located in the same place but don't convert the electricity to AC. Most of the "heavy lifting" is performed by the inverter, as conversion from AC to DC is what requires the most mechanical work by a solar PV system. Our optimizers work through DC energy modulation, so the input and output is both DC electricity making them highly robust.
A lot of work means a lot can go wrong, and you should do your own research to find that the first and most common thing to fail in a solar setup is the inverter, so it is ideal to mount in a place easily accessible for repair/maintenance. This is also why it is generally recommended that system owners mount their inverters in locations where they will not get too hot, which can damage the conversion mechanism and decrease over all efficiency. A lot of off-grid systems will have a DC coupled ESS battery, because converting DC to AC takes a lot of energy and AC to DC converting equipment is less robust than its DC to DC counterparts.
When deciding between optimizers and microinverters, the most important question you should ask yourself is: "Is my system too small to wake up a traditional inverter?" If the answer is yes, then microinvert! If the answer is no and you still want microinverters, you should ask yourself if it is worth potentially decreasing the efficiency of your system and introducing extra points of failure.I hope my answer helps you understand the difference, and gives you insight into the reasoning behind decisions people make in our industry every day!Wishing you sunny days,
Jesse Campbell You hit the nail right on the head! There are a lot of myths and misconceptions out there regarding module level electronics, and have been for a very long time. In fact, I devoted an entire section to them in my book. Aside from the glowing review of Tigo's reliability, you touched on something much broader. Since some type of MLE is required for rapid shutdown, until we get a wide availability of products listed to UL 3741, it makes good business sense to use something with the fewest parts up there to reduce the number of truck rolls and to reduce the level of risk to the installer who will have to go back up there to swap out failed or worn out MLE's.
Microinverter fanboys confuse system reliability with system availability. Having x number of extra components on the roof doesn't make it more reliable since there are more points of failure. Sure, if one micro goes bad then the system is producing 1/x amount of power as opposed to 0 watts if the string inverter goes down. But which is a less risky replacement? I don't know how many people actually thing about things like this. Thanks for chiming in!
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