Yes, a solar-diverting charger can fill your EV with sunshine, but check the prices first. In July 2026 a solar kWh earns 12p exported on Octopus Outgoing,[2] while overnight EV-tariff import costs 8p.[4] At those rates you make 4p per kWh by exporting the solar and charging the car from the grid at night. Solar charging wins mainly when your export rate is poor or your import rate is high.
- Typical system
- 3.5kWpabout £7,000 installed (EST)
- Export rate
- 12p/kWhOctopus Outgoing, July 2026
- Overnight import
- 8p/kWhIntelligent Octopus Go
- Daytime cap rate
- 26.11p/kWhOfgem, Jul-Sep 2026
- Export vs car spread
- 4p/kWhin favour of exporting
How does solar EV charging work?
Physically, easily. A solar-diverting charger, of which the myenergi zappi is the best-known UK example, watches your generation and steers surplus power into the car instead of the grid, adjusting as clouds pass.[6] Any ordinary wallbox can also simply charge while the sun is out, using whatever mix of solar and grid the house happens to be drawing.
Scale is the first reality check. A typical UK domestic array is 3.5kWp,[1] while a wallbox draws 7.4kW flat out, so panels alone rarely feed a full-speed charge; diverters solve this by charging more slowly, at the pace of your surplus. Fine for a car parked at home on sunny days, useless for a car at work when the sun is doing its best work. That mismatch matters more than any hardware choice.
What is a solar kWh actually worth?
The question that decides everything. Each kWh your roof makes has three possible destinations, and in July 2026 they pay very differently:
Value of one solar kWh by destination, July 2026
Powering the house always wins: every kWh the panels cover is an import you did not buy at 26.11p.[5] The interesting contest is between the car and the export meter. Octopus Outgoing pays a flat 12p for exports (cut from 15p in March 2026[3]), while Intelligent Octopus Go imports overnight at 8p.[4] Divert a kWh into the car and you save 8p of night-time import but give up 12p of export income. The sunshine is literally worth more sold than driven.
When does charging the car from solar win?
Whenever either side of that spread moves against you:
| Your situation | Solar kWh to car worth | Verdict |
|---|---|---|
| Outgoing at 12p, EV tariff at 8p | 8p vs 12p export | Export instead |
| Standalone SEG at 4.1p, EV tariff at 8p | 8p vs 4.1p export | Divert to car (+3.9p) |
| No export registration at all | 8p vs 0p | Divert to car |
| No EV tariff, daytime import at 26.11p | 26.11p vs 12p export | Divert to car (+14.11p) |
The pattern: solar charging is a fix for bad rates, not a bonus on good ones. If you have not switched to an EV tariff, the panels rescue you from 26.11p charging, but the £400-a-year rescue is switching tariff, which requires no hardware. If your installer never registered you for export payments, fixing that pays better than any diverter setting.
Should you buy solar panels for your EV?
Buy them for the house; let the car be a bonus. The Energy Saving Trust puts a typical 3.5kWp system at about £7,000 installed, saving £300 to £700 a year on bills plus £270 to £400 in export income at July 2026 prices.[1] Those are the numbers that justify the roof scaffolding. The car then adds, at best, a few pence per kWh of optimisation on top, whichever direction the spread points.
Home batteries complicate the picture in an interesting direction: time-of-export tariffs like Intelligent Octopus Flux pay a premium (up to 30.31p/kWh) for evening-peak exports from stored energy,[3] which strengthens the sell-the-sunshine case further for battery households. The more flexible your kit, the more the answer is “trade, do not hoard”.
If you are specifying a charger anyway and expect the car to be home on sunny days, a diverter-capable unit like the zappi (priced by quote rather than listed[6]) keeps your options open as rates change. If the car commutes, an ordinary wallbox from our installation cost guide plus a good export tariff does the same job with less ceremony.
The bottom line
Solar and EVs are a happy pairing, just not the way the brochures draw it. Cover the house first, sell the surplus at the best export rate you can get, buy the car’s electricity at 8p in the small hours, and let arithmetic, not sentiment, decide which way the sunshine flows.