Free template · off-grid solar

The off-grid solar sizing template — a balanced system, not a parts pile.

Off-grid sizing ties loads, sun, storage, and voltage together — miss one and the system browns out in winter. Fill this in yourself — each field has a plain-English hint — or answer a short interview and SpecBuildr sizes it for you.

Fill it in for me → Free · no account · ~5 minutes

The template

Copy it into your doc, or print this page. Every field carries a plain-English hint.

1.0 The site

Location & sun hours____________ (your latitude and worst-month sun decide everything)

Mounting____________ (roof or ground — plus snow, shade, wind)

Off-grid or backup____________ (full independence vs. grid-tied with reserve)

2.0 The loads

Load list____________ (everything you'll run, with watts)

Daily energy____________ (add it up in watt-hours per day)

Largest surge load____________ (the well pump or compressor that has to start)

AC / DC needs____________ (what runs on which)

3.0 The system

System voltage____________ (12 / 24 / 48 V — the backbone choice)

Array size____________ (watts of panel to make your daily energy in worst-month sun)

Battery capacity____________ (kWh banked for night and clouds, and the chemistry)

Days of autonomy____________ (how long it rides through weather with no sun)

Inverter size____________ (continuous watts + surge for the biggest start)

Backup source____________ (generator, grid, or none — the winter fallback)

Pre-quote checklist

Before you send it out, the mistakes vendors see every week:

Daily watt-hours computed, not guessed — the whole design hangs on it.
Sized for worst-month sun — July numbers lie about December.
Surge covered — the inverter must start the pump, not just run it.
Autonomy is explicit — pick the cloudy-day count on purpose.
Array can actually recharge the bank — after a bad stretch, in real sun.
Local code checked — a licensed review before anything permanent.

Or skip the blank page entirely.

Answer a short interview — SpecBuildr fills this exact structure in for you, checked for major violations, ready to send for a quote.

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