Solar calculator
Check your appliances and enter the cottage postal code: we estimate the panels, batteries and generator hours of an off-grid cottage used all year, with the real sun of your region, day by day.
What needs to keep running?
Estimated peak: 1.7 kW
Solar data source
Real sun from 1998 to 2020 at the nearest station, day by day (Environment Canada), reduced in winter for snow on the panels.
Estimated output of 6 panels in Quebec, compared with your daily consumption.
The sun covers your consumption from January to October. Up to 2 kWh per day is missing in November and December: the batteries, then a generator, take over.
- Solar output
- Not enough sun
- Consumption: 6.9 kWh/day
- hGenerator hours in the month
Frequently asked questions: off-grid solar in Quebec
The calculator’s rules, explained simply.
How many solar panels for an off-grid cottage?
Enough to cover your consumption every day of the weakest month from February to October, with the sun of your region. From November to January, the sun is too low in Quebec for a reasonable number of panels: a backup generator takes over for a few hours. The calculator starts from your appliances and postal code.
How many batteries does a cottage need?
Enough for 2 days without sun for a cottage used all year, and 1 day for a summer cottage, counting 90% usable capacity for LiFePO4 batteries. For example, 9 kWh per day for 2 days needs 18 usable kWh, or 2 × 10 kWh batteries.
Why is a generator needed in winter?
In December, a panel produces about three times less than in June in Quebec (about 1.7 peak sun hours per day versus 5). In the calculation, the generator starts when the batteries drop to 20% and charges them back to 80%; the calculator estimates its hours per year, month by month, and for the worst year.
Do more batteries reduce generator hours?
Yes, but less and less: each extra battery covers one more grey day without replacing the missing winter sun. The calculator compares several numbers of 10 kWh batteries with the same panels, to see where to stop.
Where does the sun data come from?
From Environment and Climate Change Canada: real hour-by-hour sun from 1998 to 2020 (CWEEDS data), at the weather station nearest your postal code. To be cautious, winter production is reduced for snow on the panels.
My cottage is connected to the grid: which calculator should I use?
The solar payback calculator: it compares Hydro-Québec rates (rate D, net metering, Flex D), installation cost, the LogisVert subsidy and payback years.
See also: Solar payback calculator · Find my system · FAQ