Will a Home Battery Fill Up in Winter? Halifax Solar Output, Month by Month

ElectriFusion Solutions · 15 October 2026

The question behind most battery enquiries from Halifax is simple: how much of the day's solar will the battery actually catch? The answer swings so far through the year that an annual figure hides it. Here is the whole year for a south-facing roof in Halifax, from the European Commission's PVGIS model.

A 4.85 kW array in Halifax, every month

PVGIS 5.2, SARAH2 radiation database, Halifax town-centre coordinates, south-facing at 35°, 14% system losses, fetched 15 October 2026. Annual total 4,455 kWh (919 kWh per kW), about 6.3% less than Doncaster. Modelled averages, not a guarantee for any particular roof.

The best month here is May at 575 kWh (18.5 kWh a day) and the worst is Dec at 136 kWh (4.4 kWh a day), a ratio of 4.2 to one; that ratio, not the annual total, is what a battery has to live with.

For scale: PVGIS puts the in-plane irradiation on that roof at about 1,124 kWh per square metre a year, and the array converts it to 919 kWh per installed kilowatt; a Halifax household with the regional average evening load would see the battery cycle fully on about 214 days a year on these figures.

What that means for the battery

A 5 kWh battery wants roughly 5 kWh of surplus after the house has taken what it uses during the day. On the PVGIS averages, a Halifax roof clears 10 kWh a day in Mar, Apr, May, Jun, Jul, Aug, Sep, so those are the months a 5 kWh battery fills from the roof on an ordinary day. A 10 kWh battery needs about 16 kWh a day of generation to fill from solar alone, which this roof averages in Apr, May, Jun, Jul, Aug.

From November to January the average is 5.1 kWh a day. A house that runs a fridge, a router, a kettle and some lighting through the day uses most of that as it arrives, so the battery sees a few hundred watt-hours of surplus, not five kilowatt-hours. That is not a fault with the battery or the panels; it is the latitude.

That something else is the grid

The grid fills the gap. A time-of-use tariff charges the battery overnight at the low rate and the house draws it down through the evening peak; from November to January that is where almost all of a Halifax battery's saving comes from, and from May to August the roof does the filling instead. Both halves are rate gap times kilowatt-hours shifted.

One caution: do not add grid-charging savings on top of solar savings for the same day. A battery that charged overnight is already full when the morning surplus arrives, so the summer saving is one or the other.

So what size for a Halifax home?

Measure the evening. The kilowatt-hours used between the panels switching off and bedtime are what the battery has to cover, and a smart meter's half-hourly export tells you in a week. In Halifax a typical three-bedroom semi lands at 5 kWh; a larger house with an EV or a heat pump justifies 10 kWh, mostly for the overnight charging rather than the roof. The sizing and registration details are on our battery storage Halifax page, and the panels themselves on solar panels in Halifax.

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