How to Charge Your EV for Free (If You Have Solar Panels)
Eliis Oru
March 31, 2026
Spring is here. Your panels are producing more than ever. But if your car charges at night, most of that energy never reaches your battery. Here's what's happening, why it costs more than it should, and how to fix it in a few minutes.
Your panels peak between 10am and 3pm. Your car sits in the driveway. But the charger kicks in at midnight.
Without solar charging
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MiddaySolar exports to grid at €0.04–0.08/kWh
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NightYou buy it back at €0.30+/kWh
With Gridio solar charging
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MiddaySolar goes directly into your car – effectively free
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NightGrid only when needed (at the cheapest hours)
You're generating electricity at midday, getting almost nothing for it. Then buying it back at 5–8x that rate in the evening. Every single day.
The obvious workaround is to set a timer for midday charging. But solar output changes every day depending on cloud cover, season, and how much your household is already consuming. A timer set for noon in June is wrong in March and useless on an overcast afternoon. Doing this manually means either being very conservative (and missing solar hours) or constantly adjusting – which nobody does.
How Gridio solar charging works
Plug in when you get home. Gridio handles the rest – cheap grid overnight, solar through the day.
Battery charge levelSolar outputCheap tariff chargingGridio waits — prices too high
Solar by day. Cheap tariff overnight. Full battery – every day.
Plug in when you get home. Gridio handles the rest – cheap grid overnight, solar through the day.
Solar by day. Cheap tariff overnight. Full battery – every day.
Your car follows the sun – automatically. No schedules. No manual switching.
🏠Your roofPanels generate surplus solar
→
⚡GridioReads solar output in real time
→
🚗Your EVCharges at the right time
TeslaFully dynamic modulation
Charging power mirrors solar output continuously. 2 kW of surplus → 2 kW of charging. 5 kW available → 5 kW into the battery.
Solar precisionHigh
All other supported EVsSmart threshold charging
Gridio starts or adjusts charging when your solar surplus hits your chosen threshold. You control how much grid import you allow.
Solar precisionGood
Smart meter connected? Gridio reads your actual household consumption too. If you turn on the oven, charging automatically adjusts – so you're always using genuine surplus.
Supported solar inverters
SolarEdgeSMAFroniusHuaweiFerroampGrowattKostalSofarSolaxSolisSungrow+ more coming
Don't see yours? Email support@gridio.io and the team will prioritise adding it.
This works even if you're on a fixed tariff
Solar charging is often assumed to be mainly for people on dynamic electricity contracts. But if you're on a fixed tariff (common in Belgium and the Netherlands), the logic is even more straightforward.
Every kWh from your roof is effectively free – you've already paid for the system. Every kWh from the grid costs around €0.30. Solar charging simply replaces paid electricity with your own.
Gridio solar charging works with both contract types
Fixed tariff
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Enter your tariff manually in the app
Gridio prioritises solar-first charging
Every solar kWh replaces a paid grid kWh
Dynamic pricing
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Available in NL, BE, and all Nordic markets
Gridio combines solar surplus with live spot prices
Charges from grid only at the cheapest hours
Either way, solar always comes first. The grid fills in the rest – as cheaply as possible.
Spring is the best time to start
Solar production peaks between March and May across Belgium and the Netherlands. Belgium's reported that solar generation grew 21% in 2025 and is forecast to exceed grid demand by 1.5–2 GW on bright spring days this year.
Even a car that's home only part of the day (on weekends or work-from-home days) can see meaningful solar coverage during these months.
Real simulation data · 10 kWp solar
1
Plug in & charge immediatelyNo optimisation. Charges at full power whenever plugged in.~€599per year
2
Smart charging onlyShifts charging to cheapest off-peak hours. No solar.~€463per year€136 saved vs immediate
3
Smart charging + solarSolar when available, cheapest grid hours for the rest.€371–457per yearUp to €228 saved vs immediate
Each solar kWh charged instead of grid electricity saves €0.12 net – after accounting for lost feed-in revenue.
For Nordic drivers
Your solar season is shorter, but spring and summer output is strong, especially in Denmark, southern Sweden, and southern Finland. Gridio typically combines solar charging with dynamic price optimisation for Nordic users, so the app uses your solar when available and charges from the grid at the cheapest overnight prices when it isn't. Both angles working at once.
Get started in minutes
No hardware. No electrician. Just smarter charging.
1
Download the Gridio app
2
Pair your electric car or plug-in securely
3
Connect your solar inverter
4
Tell when the car should be ready
5
Gridio handles the rest automatically ☀️
If you already invested in solar, this is how you finally get the full value from it.
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