Winter is coming to an end, spring has begun and the temperature is rising, and this also applies to your gaze. There may be some hot dirt on the top of your solar inverter, as even the best ones can suffer bird nests.
Are bird nests bad for solar inverters?
When not in your garage, solar inverters should be in a nice, sheltered location, often on the quieter side of the house. In winter they form a nice warm substrate and provide a refuge for nesting birds. This can cause the inverters to overheat.
New residents move in
My Fronius Primo Snap inverter, which was located under the side veranda of the house, appeared to be uninhabited at first glance.
Since the top of the inverter was 2.4 meters above the ground, everything seemed fine.
Upon closer inspection, it seems we have a problem.
Of course, birds don’t loudly announce that they’ve moved in to raise a family, and even though they were right in front of the laundry, no one noticed the collection of sticks and branches that crowned our solar array.
What’s the problem?
Clear demonstration of a hard working inverter. The fan-cooled Fronius on the left runs cooler, while the ABB/Fimer on the right roasts quietly
Solar inverters must be able to dissipate heat. Suppose you have a device that produces 5 kW of electricity with 95% efficiency. This means that 250 watts of waste heat must be dissipated, practically the same amount as a bathroom heat lamp (which, by the way, has its own fan).
Whether powered by a fan or simply relying on convection, placing a blanket of dry leaves and matted garden crops on top will restrict air circulation and cause the temperature to rise.
No amount of fan cooling could solve this mess, the parallel fins of the heatsink were completely blocked.
Your inverter has internal sensors that ensure the temperature is no more than 20°C above the ambient temperature, so there is no risk of the chicks being grilled on the flame. However, excessive heat means yields suffer.
To keep things under control, the inverter is simply throttled down and the throughput is reduced. No matter how sunny it is, it won’t help your bills.
Depending on the model, Fronius Snap inverters can have one, two or even 3 fans. These outside air intake grilles on both sides should be checked regularly.
Heat kills
We’re not talking about fried eggs or animal welfare here: the old maxim is that heat kills electronics.
Every 10°C increase in operating temperature halves the expected lifespan of electronic components.
It’s a rule of thumb based on the Arrhenius equation that describes how the rate of chemical reactions accelerates with temperature, leading to faster degradation and earlier failure of things like capacitors.
It appears that a combination of the spider web and proximity to the laundry with its abundance of textile fibers creates a noticeable mat on these air intake grilles.
Fans are cool
The Fronius people know it, and if they’re honest, the quiet guys realize that even larger Sungrow devices have forced cooling on the back.
By using appropriate thermal management, you achieve higher yield and longer lifespan, as well as making the devices lighter and more cost-effective. Using a fan is far smarter than bolting on a huge aluminum heatsink and hoping the problem resolves itself.
Fronius has a fan test function if you go directly to the menus. The first step, however, is to keep the grids clear
Maintenance matters
The front heatsink isn’t blocked too badly here, but it’s still far from ideal.
It’s important to keep fans away from geckos, spider webs, and the like, but the same goes for passively cooled heatsinks. Pointing a garden blower at them every now and then won’t hurt.
That’s exactly what this whole post is about. It’s worth taking an occasional look at your solar system to make sure nature isn’t trying to reclaim the resources you’ve invested in.
For more information on solar maintenance, read: Why inspecting your systems every five years is a smart idea.
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