Solar Generator Calculator - Portable Power Station Sizing | SolarRatio
Find the right portable solar generator size for your needs. Calculate required battery capacity (Wh) and solar panel wattage for camping, emergency backup, or off-grid use.
Solar generator sizing converts intended use cases — emergency backup, camping, RV supplemental, jobsite tools — into the right combination of battery Wh, inverter VA, solar input W, and AC output ports. The portable solar generator market spans 200 Wh handheld units to 6,000 Wh wheeled systems with 240V split-phase output. Picking the wrong size means either dragging too much weight to a 2-day campsite or running out of power during the third hour of a hospital home-care event. This tool grounds the decision in actual Wh demand and recharge realism. In the US, solar generators have become a go-to solution for hurricane-prone states like Florida and Texas, where grid outages can last days; a 2,000–3,000 Wh unit paired with 400 W of panels can sustain critical loads at Miami's 5.5 h/day PSH indefinitely, while the same unit in Seattle (3.7 h/day) may need grid or generator top-up after two sunless days.
How it Works
List intended loads with wattage and runtime, sum daily Wh demand, and add 20–30% safety margin for inverter efficiency and battery DoD limits. The recommended battery Wh = demand × autonomy hours ÷ 0.85. Inverter VA must exceed the largest single load × surge multiplier (e.g., a 1,200 W microwave needs at least 2,000 W inverter capacity). Solar input W determines recharge speed: a 200 W panel into a 1,000 Wh generator yields 5–7 hour recharge under good sun; 400 W into 2,000 Wh achieves similar duty cycle. The tool also flags AC output count and DC port compatibility (USB-C PD, 12V cigarette, anderson connectors) so the chosen unit fits the actual gear list.
Usage Scenarios
Emergency-prep households in hurricane-prone Florida or Texas pick a 2,000–3,000 Wh wheeled solar generator with 1,800 W AC output to run a fridge, modem, lights, and CPAP for 24–48 hours during grid outages, relying on 5.5 h/day Miami or Texas PSH for fast daily recharge. Weekend campers and overlanders carry 500–1,000 Wh portable units paired with a 100–200 W foldable panel for phone, laptop, drone, and lighting. Construction crews use 2,000–4,000 Wh units to run cordless tool chargers, jobsite radios, and lighting in remote new-construction sites without generator noise or fuel. Vanlife and RV users supplement their built-in system with a portable unit deployed under shaded campsites where the rooftop array can't harvest. Medical-equipment-dependent households spec a unit with sustained output sufficient for oxygen concentrators (300–600 W continuous, 24/7) plus margin.
Frequently Asked Questions
What size solar generator do I need for camping?
For light camping (phone charging, LED lights, laptop): 500–1000Wh. For a fridge and CPAP machine: 1000–2000Wh. For a small AC unit or high-power tools: 2000–3000Wh. Use this calculator to find your exact requirement based on daily consumption and backup days needed.
How many solar panels do I need for my portable power station?
Required panel watts = daily Wh / (peak sun hours × efficiency). For 1000 Wh/day at 4.5 peak sun hours and 85% efficiency: 1000 / (4.5 × 0.85) = 261W. Most power stations accept 100–600W of solar input — check your unit's max solar input rating.
What is the difference between a solar generator and a portable power station?
They are essentially the same product. A portable power station is the battery unit with built-in inverter and AC/DC outlets. A solar generator refers to the complete system: power station + solar panels. Most major brands sell both individually and as a bundle.
How long does a 1000Wh power station last?
At 80% usable capacity (LiFePO4), a 1000Wh station gives you 800Wh of usable energy. Runtime: laptop (60W) = 13 hours, LED lights (10W) = 80 hours, mini fridge (50W) = 16 hours, CPAP (30W) = 27 hours. High-draw appliances reduce runtime significantly.
Can a solar generator power a house during an outage?
A 2000–3000Wh power station can run essential loads (lights, phone/laptop charging, small fridge, internet router) for 1–2 days. For whole-home backup, you need a much larger system (10–20 kWh). Solar generators are best for critical loads, not full-home backup.
How to Use the Solar Generator Calculator
Enter daily power consumption (Wh), days of autonomy for cloudy periods, battery type, and inverter efficiency. Formula: Required battery (Wh) = daily Wh × autonomy days / (DoD × inverter efficiency). The calculator maps the result to the nearest standard portable power station size.
Common portable power station sizes: 500Wh, 1000Wh, 1500Wh, 2000Wh, 3000Wh, and 5000Wh. The calculator recommends the smallest standard size that covers your requirement. Size up if your required capacity exceeds the nearest standard size.
Solar panel sizing: required watts = daily Wh / (peak sun hours × efficiency). For 1000 Wh/day at 4.5h and 85% efficiency: ~261W of panels. Most portable power stations accept 100–400W of solar input.