RELATED: Can I have a home battery without solar panels?
How overnight charging works
The idea is simple. Buy electricity when it is cheap, store it, and use it when the grid price is high.
Smart tariffs sell power in a low overnight window. Your battery fills up while you sleep. Through the day it runs the house on that stored power, so you stop buying units at the expensive daytime rate.
No solar is required for this. Solar and night rate charging both fill the same battery. Many homes end up doing both, solar in summer, night rates in winter. If you have no panels, the overnight route stands on its own.
The savings on current rates
The saving comes from the gap between the two rates.
| Rate | Price per kWh | When |
|---|---|---|
| Off peak overnight | around 7p to 8p | the cheap night window |
| Standard variable | 26.11p | the rest of the day |
That is roughly 19p of difference on every unit. A battery loses a little in the round trip, so you get back about 85 to 90 percent of what you store. Even after that, a 10kWh battery cycled daily keeps a household around £500 to £600 a year on current rates. Bigger daily use, bigger saving.
RELATED: Already running an EV at home? Compare tariffs on our best EV tariff guide.
Does your tariff and battery need to match
This is where honesty matters. Not every cheap rate suits a battery.
Some tariffs apply the low rate to your whole home during the overnight window. Any battery that can be scheduled to charge in that window will benefit. That is what you want.
Other tariffs only give the cheap rate to power drawn through an approved EV charger. On those, a battery on its own may not qualify. We check this before we quote.
You do not always need an EV to get an off peak tariff, though some of the cheapest ones are aimed at EV drivers. You do need a smart meter. Your battery also needs to be set up to charge in the right window, which we handle at install. We are not tied to one manufacturer, so we match the hardware to the tariff you want to use.
For the full picture on how we design, install and monitor storage, visit our battery storage installation page.
