- Panels make DC power; a microinverter turns it into AC that is synchronized with the grid.
- Solar power flows to the nearest appliances that are running. It covers part of your home’s use; the grid supplies the rest.
- If the grid goes down or you pull the plug, the inverter stops within a fraction of a second.
- Your meter only sees the net result: less electricity drawn from the grid.
People are often surprised that you do not need to plug your TV into the solar panel to use its power. Once you understand what the microinverter does, the whole system makes sense.
In this article
Step 1: panels turn sunlight into DC electricity
Each solar cell produces a small voltage when light hits it. A panel wires dozens of cells together to reach around 30-45 volts of direct current (DC). The output rises and falls with the amount of light: a 400 W panel produces close to 400 W only in strong, direct sun with the panel facing it squarely, and far less on cloudy days or when light arrives at a steep angle.
Step 2: the microinverter converts DC to AC
Your home runs on alternating current (AC), 120 V at 60 Hz in North America or 230 V at 50 Hz in Europe and the UK. The microinverter is a small box, usually mounted behind the panel, that does three jobs:
- Maximum power point tracking (MPPT). It constantly adjusts how much current it draws from the panel to extract the most power at that moment. Many inverters have two MPPT inputs so each panel is optimized separately.
- Conversion. It turns DC into AC with an efficiency of around 95-97%.
- Synchronization. It measures the grid’s voltage and frequency at the outlet and produces AC that is exactly in step. Without a grid signal to follow, it will not produce anything.
Step 3: power flows to whatever is running
Once the inverter pushes current into the outlet, it joins your home’s wiring. Electricity follows physics, not labels: the solar power goes to the loads that are drawing current, starting with those closest on the circuit. If your home is using 350 W and the panel is making 250 W, the grid supplies 100 W. If the panel makes 500 W while you use 350 W, the extra 150 W flows back out through your meter to the grid.
What your meter sees
- Modern digital or smart meters record import and export separately. You pay for imports; exports are usually not credited for plug-in kits.
- Old spinning-disc meters can run backwards when you export. That sounds nice, but in many places it is not allowed. See will plug-in solar spin my meter backwards?
The safety trick: anti-islanding
When a power line is down, utility workers expect it to be dead. A solar inverter that kept producing would create an “island” of live wiring. Certified microinverters detect the loss of grid voltage and shut down within a fraction of a second. The same logic protects you: pull the plug from the wall and the pins go dead almost instantly, because the inverter no longer sees a grid to sync with.
This also means a standard plug-in kit does not give you backup power during an outage. For that you need a battery system designed to run as an off-grid island, covered in plug-in solar during power outages.
Why output is capped
A household circuit’s breaker protects the wires by tripping when too much current flows from the panel. But a solar device feeds current from the other end of the circuit. If a heater drew 1,500 W from the breaker side and 1,200 W from the solar side at once, the wire between them could carry more than the breaker ever sees. Output caps (800 W in Europe and the UK, 1,200 W in most US laws) keep that risk low. More on the limits here.
Where a battery fits in
Batteries for balcony systems sit between the panels and the inverter (DC-coupled) or plug in separately (AC-coupled). They store midday surplus and release it in the evening, raising the share of solar power you actually use. We explain both designs in AC vs DC coupled batteries.
Frequently asked questions
Do I need special outlets?
No special socket is required in most places, but an outdoor, GFCI (or RCD) protected outlet on a circuit without heavy loads is the right choice. See outdoor outlets for plug-in solar.
Can I plug it into any outlet in the house?
Technically it will work on any outlet, but avoid kitchen and laundry circuits with heavy appliances, and never use an extension cord.
Does it work on a cloudy day?
Yes, at reduced output, typically 10-30% of rated power. Details for winter and clouds.