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UK Winter 12V Off-Grid Solar Calculator P2

Profile 2: size battery Ah and panel watts for UK Winter conditions at 12V using 2.3 peak sun hours and 2-day backup.

Sizing Snapshot

Daily Energy

1807 Wh

Battery Bank

363.7 Ah

Solar Array

1071 W

Inverter Baseline

1250 W

Appliance	Power	Daily Runtime	Wh/Day
Fridge (60W x 24h)	60 W	24.00 h	1440 Wh
Microwave (1000W x 10m)	1000 W	0.17 h	167 Wh
LED Lights (40W x 5h)	40 W	5.00 h	200 Wh

Low winter sun window requiring larger battery and panel overhead.

Use local monthly irradiance data to tune peak-sun-hour assumptions before procurement.

Cloud-prone months usually benefit from higher autonomy targets and larger reserve buffers.

For winter-heavy climates, panel overbuild is often cheaper than repeated battery deep cycles.

Use this for planning and shortlist decisions, then validate with measured appliance duty cycles and local irradiance history.

For this load profile, estimated LIFEPO4 bank sizing is 363.7 Ah at 12V with 2-day autonomy.

The calculator estimates 1071 W panel capacity after charge and derate factors.

For the same energy demand, lower voltage systems need more current. That translates into larger Ah requirements and often thicker cabling.