EV Charging
A charge point that prioritises your own surplus generation rather than pulling from the grid — which changes the economics of solar more than almost anything else.
Solar-aware charging • OZEV-grade installation • Load management included
An EV changes the solar arithmetic
The problem with domestic solar is that the generation and the demand happen at different times. An electric car is the most effective fix for that available to a household, because it is a large, flexible, movable load that does not mind when it gets its energy.
Charge the car on a dull weekday afternoon from your own array and you have converted electricity worth the export rate into electricity worth the price of petrol. Nothing else in a normal house shifts the numbers by that much.
Solar-aware charging
A solar-integrated charge point watches what the array is producing and what the house is using, and puts the difference into the car. Most units offer three modes:
- Surplus only — the car takes nothing but genuine excess generation. Slowest, and the cheapest energy you will ever put in a vehicle.
- Blended — surplus plus a set minimum from the grid, so a cloudy afternoon does not stall the charge entirely.
- Scheduled — full-rate charging in an off-peak window, which on a time-of-use tariff is often the cheapest option in winter regardless of what the panels are doing.
Getting real value out of this depends on the charger, the inverter and the battery talking to each other properly. That is a specification question, and it is the reason we would rather quote the charge point alongside the system than leave it to a separate contractor afterwards.
Charging the car from the battery — usually a mistake
It sounds efficient and generally is not. Putting energy into a home battery and then taking it out again to fill a car battery costs you two sets of round-trip losses, and a home battery is small relative to a car. Better to send surplus straight to the vehicle and keep the home battery for the evening peak. We will set the priorities up that way unless you have a specific reason to want otherwise.
The installation itself
A charge point is a fixed 7.4 kW single-phase load, which is a substantial addition to a domestic supply. The installation involves a dedicated circuit, the right earthing arrangement for an outdoor charge point, RCD protection to the required type, and load management so the house cannot trip its main fuse when the shower, the oven and the car all coincide.
Where the incoming supply is marginal — which is common on older properties — load management is not optional and we will say so. We notify the network operator where notification is required.
Doing it at the same time as the solar
If an EV is on the horizon, tell us now. It is markedly cheaper to run the cable and specify the consumer unit once, and knowing the car is coming changes the right array size and the right battery size today. We would rather design once for where you are heading than fit a system that is the wrong shape in eighteen months.
Send us your annual kWh figure and a photo of the roof and we will tell you what is realistic before anyone visits.
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