Off-Grid Solar Node Planner: Size a Meshtastic or LoRa Node for Canadian Winter
Quick answer
A solar node that runs happily all summer will die in December, and the reason is arithmetic: across Canadian cities the average winter insolation is roughly 1.1 to 1.5 kWh/m² per day against an annual average two to three times higher. Size a panel on the annual figure and you have built something that collects less than half the energy it needs in the month it is least accessible to fix. This planner sizes for winter by default. It also refuses to hide the failure mode that actually kills these builds, which is not panel wattage at all: standard lithium-ion and LiFePO4 cells must not be CHARGED below 0 °C. A node can have ample sun, an ample panel and a healthy battery and still fail in January because the charge controller is pushing current into a frozen cell.
Measure your node's real average current draw rather than guessing from a datasheet peak — duty cycle dominates everything. Size the panel on winter sun, add days of autonomy for consecutive overcast days, and if the battery will be outdoors in a Canadian winter, use a charger with low-temperature cutoff or a self-heating cell. Oversizing the panel is cheap; a dead node on a tower in February is not.
Read this before you buy anything. The most common cause of a dead off-grid node in a Canadian winter is not an undersized panel — it is charging a frozen battery. Standard lithium-ion and LiFePO4 cells can be safely discharged in the cold but must not be charged below 0 °C; doing so plates lithium onto the anode, permanently destroying capacity and creating a real safety hazard. If your battery lives outdoors, you need a charge controller or BMS with a low-temperature charge cutoff, a self-heating LiFePO4 cell, or an insulated enclosure that stays above freezing. This planner sizes energy; it cannot size around physics.
Size your node
Everything runs in your browser — nothing is sent anywhere. Insolation values come from D-Central's Canadian solar-resource dataset, read live rather than copied, so a correction there flows straight through to this tool.
How the numbers are worked out
No hidden fudge factors — the whole model is four lines of arithmetic, shown so you can check it or redo it on paper.
- Daily energy need.
Wh/day = mA ÷ 1000 × V × 24. Average current is what matters; a node that transmits hard for two seconds a minute is defined by its sleep current, not its transmit peak. - Usable sun.
effective peak-sun-hours = insolation (kWh/m²/day) × winter derate. Insolation in kWh/m²/day is numerically the same as peak sun hours, which is why the units look like they vanish. - Panel size.
panel W = (Wh/day) ÷ (effective PSH × system efficiency). System efficiency covers the charge controller, wiring, battery round-trip and temperature losses. - Battery size.
battery Wh = (Wh/day × autonomy days) ÷ depth of discharge, thenmAh = Wh ÷ V × 1000. Autonomy is how many consecutive sunless days the node survives.
What this model deliberately does not do: it does not estimate your node's current draw for you. Meshtastic power consumption swings by an order of magnitude with screen, GPS, role and sleep configuration, and published figures are inconsistent. Measure yours with an inline USB meter or a bench supply over a full duty cycle, then come back. A number you measured beats any number we could have guessed on your behalf.
Winter sun across Canada
The gap between the winter and annual columns is the entire argument for sizing on winter. Sorted by winter insolation, worst first.
| City | Winter kWh/m²/day | Annual | Summer | Winter vs annual |
|---|---|---|---|---|
| Iqaluit, NU | 0.30 | 2.80 | 5.00 | 11% |
| Yellowknife, NT | 0.40 | 3.00 | 5.70 | 13% |
| Whitehorse, YT | 0.50 | 2.80 | 5.00 | 18% |
| Vancouver, BC | 1.00 | 3.30 | 5.50 | 30% |
| St. John's, NL | 1.10 | 3.00 | 4.80 | 37% |
| Victoria, BC | 1.10 | 3.60 | 5.90 | 31% |
| Quebec City, QC | 1.40 | 3.50 | 5.50 | 40% |
| Saint John, NB | 1.40 | 3.30 | 5.00 | 42% |
| Charlottetown, PE | 1.50 | 3.60 | 5.50 | 42% |
| Edmonton, AB | 1.50 | 3.70 | 5.90 | 41% |
| Fredericton, NB | 1.50 | 3.50 | 5.40 | 43% |
| Halifax, NS | 1.50 | 3.50 | 5.30 | 43% |
| Montreal, QC | 1.50 | 3.60 | 5.60 | 42% |
| Ottawa, ON | 1.50 | 3.70 | 5.70 | 41% |
| Toronto, ON | 1.50 | 3.70 | 5.70 | 41% |
| Saskatoon, SK | 1.70 | 3.90 | 6.10 | 44% |
| Winnipeg, MB | 1.70 | 3.90 | 6.00 | 44% |
| Regina, SK | 1.80 | 4.00 | 6.20 | 45% |
| Calgary, AB | 1.90 | 4.00 | 6.00 | 48% |
Read the last column as "a winter day collects this fraction of what an average day collects." Anywhere it sits near a third, a panel sized on the annual average is roughly a third of the panel you need.
Related
Canadian solar resource dataset · Meshtastic device database · LoRa regions & presets · LoRa airtime calculator · off-grid power components · generator fuel calculator
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Last reviewed July 20, 2026.