Calculators

Below are 3 handy calculators. The Off-Grid Load & System Sizer calculator sums up your total Wh/day, estimating common loads, and you can refine duty and average hours of use. The Voltage Drop Calculator compares different Cable/wire sizes (AWG) to their voltage drops over a specfic Distance. The Solar Sizing Estimator uses ProjectSunroof data to estimate either residental or mobile solar fesibility, size and cost. Use these tools at your own risk.

Off-Grid Load & System Sizer

Appliance	Watts	Hrs	Qty	Duty%	Wh/day
Total					0

Voltage Drop Calculator

Source voltage (V) Phase

One-way length

Frequency (Hz)

Enter load as Value Power factor (0–1)

Conductor material Conductor size

Or choose “Custom area…” and enter circular mils.

K constant (Estimated method): 12.9 cmil-Ω/ft @ 75 °C.

Results

Voltage drop

Drop percent

Load end voltage

Calculated current

Solar Sizing Estimator

State (US)

Sets a reasonable default for sun hours.

ZIP (US)

Refines sun-hour guess (coarse). You can override.

Sun hours (avg/day) System derate (overall)

Temp, wiring, inverter, soiling, etc.

Monthly bill ($) Utility rate ($/kWh)

Target offset (% of usage) DC:AC ratio (for inverter)

System cost ($/W DC) Incentives (% off upfront)

e.g., federal ITC 30% (excludes SRECs).

Panel wattage (W) Panel area (sq ft each)

Typical 72/144-cell ≈ 21.3 sq ft.

Results

Recommended size (DC)

Est. annual production

Panels (approx)

Roof area needed

Inverter (AC, cont.)

Annual bill savings

Net cost (after incentives)

Simple payback

Offset (%)