Comment by ButlerianJihad | Hacker News Reader

Comment by ButlerianJihad | Hacker News Reader

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https://en.wikipedia.org/wiki/Balcony_solar_power

  In the United States, Underwriters Laboratories developed the UL 3700 standard specifically for plug-in solar devices, establishing safety specifications for microinverters and connection systems used in these applications.[2] UL-certified plug-in inverters are designed to automatically shut down during grid outages, preventing backfeed that could endanger electrical workers.[7]

So that is the standard failure mode, but do customers understand how it works?

If I had a balcony solar panel, I'd definitely expect it to be providing backup power when we need it the most. I'd expect it to charge a storage battery, not backfeed into the grid.

Surface area means a lot for solar panels. An EV with a solar panel on top is laughable. I own a solar backpack that couldn't charge its power bank within 3 weeks of daily full sun. A "balcony solar panel" may not keep your smartphone charged.

The stated purpose for balcony solar is to reduce your power bill. Nowhere does it state it's for backup power. And whether it helps at all depends entirely on your own situation. If it turns out that you can generate, say, 420w for 8 hours, that's 3.3kW, which is a decent amount of power, probably 1/4 to 1/8 the total draw of many homes. That means 1/4 to 1/8 off your energy bill once it pays for the solar panel.

If you want to convert a solar panel into backup energy, there are many ways to do that, but no solar panel+microinverter are safe to just plug into your home. Whether it's a transfer switch, a "solar generator", or a grid-forming microinverter system, they all require you to be physically disconnected from the grid to continue generating power, or to have things plugged into an explicit "backup load" circuit which doesn't come from the grid.

Consumers in Germany generally understand that this is a cost-savings device, not a backup supply of electricity. You tell your neighbors and friends to get it because of the energy bill savings.

They are not as weak as the toy panels you are describing, but they are regulated to 800W max anyways.

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