Guide, 4 min read
Charging an EV from solar panels at home
A charger with solar diversion throttles the charge to match what your panels are exporting, so the car takes generation you would otherwise sell back cheaply.
Get a price
Where does it need to go? Two taps and a postcode gets you a price.
The problem solar diversion solves
Panels generate most in the middle of the day, when the house is using least. The surplus gets exported, and export rates are usually well below what you pay to import.
If the car is at home during the day, that surplus is far better used charging it. The difficulty is that generation moves constantly with cloud cover, and a charger that draws a fixed 7kW would simply import the difference.
How it works
A solar-aware charger monitors the flow at your meter using a clamp. When you are exporting, it charges at whatever rate the surplus supports, ramping up and down as the generation changes.
Most units offer a middle mode too, topping up from the grid to keep a minimum charge rate going, so the car still makes progress on a dull afternoon.
Which units do it
- Zappi, from myenergi, which is the unit most associated with this feature
- Hypervolt Home 3, which combines solar matching with tariff scheduling
- Several others offer a version of it, with varying sophistication
If you have battery storage too
Priorities need setting, because the house battery and the car are competing for the same surplus. Generally the house battery wins during the day and the car charges overnight on a cheap tariff, but it depends on your usage and your export rate.
This is worth thinking through before buying, because it changes which charger makes sense.
The honest limitation
Solar charging only helps if the car is home during daylight. For someone who commutes daily, the panels generate while the car is at work, and an overnight tariff does more for the running cost than solar diversion ever will.
Next step
Send us the postcode and we will tell you what your property needs.
Send the postcode and what the property is, and we will come back with the quote or the one question still outstanding.
Questions
EV charging questions on this
Can I charge my EV from solar panels?
Yes, with a charger that supports solar diversion. It matches the charge rate to your surplus generation so you use it rather than exporting it.
How many panels do I need to charge a car?
There is no threshold. Any surplus goes in. A larger array simply means more hours where the surplus is enough to charge meaningfully.
Is solar charging better than an overnight tariff?
Only if the car is at home during the day. For a daily commuter, off-peak overnight charging saves more, and the two can be combined.
Get a quote
Get an EV charger quote for your property
Five fields. We reply with either a fixed price or the one thing we still need to know.
- No cost, and no obligation to book anything
- Your details are never sold on or passed around
- A fixed price for the work described, in writing
Would rather talk it through? Call 07487 696567.
