A 60 kWh car battery holds six times what the Energy Saving Trust calls a typical home battery. That one comparison answers most of the question in the title, and it is why this guide keeps the two jobs apart: the charger fills the car, and a home battery, if you have one, looks after the house. Fitting the charger itself in CM17 to CM20 is covered on our Harlow EV charger page.
The number of cars asking the question is rising quickly. DVLA records about 1,940 privately kept plug-in vehicles across Harlow district at the end of June 2026, up from 1,322 a year earlier: 618 more, about 47% (our arithmetic). Harlow Council is building EV charging into its own new homes, too: Staple Tye Depot, completed on 7 April 2026, and Parnall Road, completed on 11 June 2026, are described as supporting carbon reductions through solar panels and EV charging points.
The arithmetic
The Energy Saving Trust says a typical home system might be 10 kWh, and that there is no exact formula for sizing one. Against a 60 kWh car battery, a full 10 kWh home battery adds a sixth of a charge (our arithmetic). A 7 kW charger delivers roughly 7 kWh an hour, so running from the battery at full rate it would take most of the battery’s contents in about an hour and a half. In a Harlow terrace, where 45.0% of the built-up area’s households lived at the 2021 Census, that would leave the car a sixth fuller and the house back on grid power for the whole evening.
What a home battery is sized to
Ofgem’s typical domestic consumption value from 1 July 2026 is 2,500 kWh a year, about 6.8 kWh a day if spread evenly (our arithmetic). A home battery is sized against loads of that order, and against the evening part of them in particular, not against a car. That is why the batteries we fit, EnSmart systems, are sized at the survey from the household’s own use rather than from the car’s battery size. Our page on battery storage in Harlow explains how we size one to a house.
Where the car’s energy comes from instead
For the car, the cheaper store is the grid at night. Since 30 June 2022 every new home chargepoint sold in Great Britain has had to be smart, with default charging hours outside the regulations’ peak hours of 8am to 11am and 4pm to 10pm on weekdays. A car plugged in at a Sumners or Church Langley home in the evening can wait for the off-peak window of an EV tariff and charge through the night. At roughly 7 kWh an hour, a 60 kWh battery fills from empty in about eight and a half hours (our arithmetic), and a partial top-up takes proportionally less. No battery sits in that chain.
Where a battery and a charger do work together
There are honest reasons to have both. A battery can carry part of the house’s evening load through the 4pm to 10pm peak while the car waits for its overnight window, so the two are not competing for the same hours. With panels and a compatible setup, a summer surplus can go to whichever you set first. On PVGIS figures a south-facing 4 kWp roof in Harlow averages about 16.2 kWh a day in June but only about 4.5 kWh a day in December (our arithmetic), so in a Harlow winter there is little surplus for either the battery or the car. What a battery should not be asked to do is refill the car every night.
One supply carries both
Both machines sit behind the same main fuse. A 7.4 kW charger draws 32 A continuously; domestic main fuses are commonly 60 A, 80 A or 100 A, and on 60 A the charger alone leaves 28 A for the rest of the home (our arithmetic). Load management turns the charger down while the house is busy. Where that cannot cover the demand, UK Power Networks says it can upgrade a 30 A or 60 A main fuse to 80 A or 100 A, and if your supply is looped with a neighbour’s, the change has to be planned with both households and may carry a charge.
Central Harlow sits in UK Power Networks’ Eastern Power Networks licence area, about 10.4 km from the London network boundary. The installer notifies UKPN of the chargepoint, and a battery’s inverter goes through the network operator’s own notification or approval route, so a combined job carries two sets of paperwork, both handled by the installer rather than by you. Our home EV charger installation guide covers the charger’s side in full.
Harlow homes: who can say yes
Before any of this, check who decides. At the 2021 Census, 23.9% of Harlow district’s households rented directly from the council and 15.4% privately, and for them a charger or a battery is the landlord’s decision first. The 27.5% of households in flats need the freeholder’s consent. Most Harlow homes carry restrictive covenants administered by the council, though not in Church Langley, where the developers’ covenants in the deeds apply instead; our guide to Harlow covenants and where a battery can go works through that for a battery.
On grants, renters and people who own and live in a flat, with private off-street or allocated parking, can get OZEV’s grant of 75% of a chargepoint’s cost up to £500 per socket. It must be made through an OZEV-authorised installer; tell us your situation at the quote stage. Owner-occupiers of houses get no grant, and OZEV’s grants cover chargepoints, not batteries. Our guide to who qualifies for the EV chargepoint grant sets out each case. A home charger installation carries 20% VAT.
Power cuts are a separate question
Neither a charger nor a standard grid-tied battery keeps a Harlow car charging in a power cut. A battery provides backup only if the specific system and installation are designed for it, with extra equipment and wiring, and any quote should say in writing whether that is included. If backup matters to you, raise it at the survey as its own requirement rather than assuming a battery brings it.
Sources: Department for Transport and DVLA, VEH0142 licensed plug-in vehicles by keepership and local authority, Harlow, private keepers, end of June 2025 and end of June 2026 (published 23 September 2026); Energy Saving Trust, Battery storage (last updated 19 August 2026); Ofgem, Typical Domestic Consumption Values (from 1 July 2026); legislation.gov.uk, The Electric Vehicles (Smart Charge Points) Regulations 2021, regulations 1 and 10, read 19 October 2026; PVGIS 5.3 (European Commission JRC), PVGIS-SARAH3 2005–2023, 4 kWp, 35° tilt, due south, 14% system losses, run 15 October 2026; ONS, Towns and cities, characteristics of built-up areas, Census 2021, tables 1c and 5c, Harlow BUA; ONS Census 2021, TS054 Tenure (Nomis), Harlow; Harlow Council, Staple Tye Depot and Parnall Road development pages, and Covenant control; OZEV, Changes to electric vehicle chargepoint grant schemes from 1 April 2026 (updated 7 July 2026); UK Power Networks, fuse upgrade guidance and Licence Boundaries open dataset (17 December 2024); NESO, GIS boundaries for GB DNO licence areas (3 May 2024); HMRC, VAT Notice 708/6.