Solar generator sizing: loads first, panels second
A portable solar generator usually combines a battery power station with compatible panels. Size two things separately: energy you need to deliver, and energy you can replace before the next use.
1. Build a realistic load list
For each device, multiply average watts by hours of use. For cycling appliances such as refrigerators, measured daily energy is more useful than the instantaneous running watts. Include devices that run at the same time when checking output power.
Illustrative load budget
A 60W average laptop for 5 hours uses 300Wh. A 15W network setup for 8 hours uses 120Wh. A 10W light for 4 hours uses 40Wh. Total: 460Wh delivered. These are example inputs, not appliance test results.
2. Account for usable energy once
Nominal capacity needed = load energy ÷ (overall usable factor × available fraction after reserve).
With an illustrative 85% usable factor and 10% reserve, 460 ÷ (0.85 × 0.90) = about 601Wh. The usable factor already combines conversion and accessible-energy assumptions; do not add another generic “20% inverter loss” on top. Actual measured efficiency may differ.
Calculate with your load list3. Estimate solar replenishment
Panel watts × peak-sun-hours × an assumed combined derating factor gives an illustrative daily harvest. For example, 400W × 4 hours × 0.75 = 1,200Wh. Four hours of daylight is not necessarily four peak-sun-hours; cloud, shade, angle and season matter.
To replenish 2,000Wh with the same assumptions, the arithmetic calls for about 667W of panel rating. This is an energy estimate, not a compatible wiring design. A 400W panel setup cannot be assumed to refill 2kWh in one day.
4. Check compatibility before ordering
- Use the manufacturer’s permitted input voltage, current and wattage, not just connector shape.
- Confirm panel open-circuit voltage including the manufacturer’s temperature guidance.
- Check cable and connector requirements in both manuals.
- Confirm any combined-input restrictions for the exact model.
Turn the budget into a shortlist
If your required capacity exceeds 1,024Wh, the DELTA 3 Plus by itself is below the target. Compare larger options or a documented recharging plan. For solar recharge, then compare the input specification and panel compatibility.