ILLUSTRATIVE PROJECT · NO EQUIPMENT APPROVAL
A small backup-load exercise
A fictional refrigerator, lights, router and charging plan. Replace these figures with actual labels, measurements and conditions for a real plan.
| Load | Quantity | Running W each | Hours/day | Duty | Wh/day |
|---|---|---|---|---|---|
| Illustrative refrigerator | 1 | 100 | 24 | 40% | 960 |
| Illustrative LED lights | 4 | 8 | 5 | 100% | 160 |
| Illustrative router | 1 | 12 | 24 | 100% | 288 |
| Illustrative chargers | 2 | 10 | 2 | 100% | 40 |
Carry an explicit battery assumption.
5,000 Wh nominal × 90% assumed usable share × (1 − 20% reserve) = 3,600 Wh before conversion. At 90% assumed inverter efficiency and no DC/standby load, that is 3,240 Wh delivered AC: 2.24 equivalent load-days at this daily energy use.
The saved runtime exercise uses daily Wh ÷ 24 as a constant average AC load. That average does not reproduce an appliance schedule, actual outage window or starting surge. Temperature retention is assumed 100%; output ratings, degradation, charging, actual weather and compatibility are unresolved.
Questions this exercise does not settle
- What are the exact starting/continuous ratings and documented energy boundary?
- Can the selected equipment operate together in the intended configuration?
- What seasonal production, cloudy sequences and charging limits apply at the actual location?
- What protection, mounting, permits, utility conditions and professional design checks are required?
ILLUSTRATIVE PROJECT · NO EQUIPMENT APPROVAL
An evening camping-load exercise
A fictional light, fan and charging plan with different daily use. Replace these figures with actual labels, measurements and conditions for a real plan.
| Load | Quantity | Running W each | Hours/day | Duty | Wh/day |
|---|---|---|---|---|---|
| Illustrative camp lights | 2 | 6 | 4 | 100% | 48 |
| Illustrative fan | 1 | 25 | 8 | 100% | 200 |
| Illustrative phone charging | 2 | 10 | 2 | 100% | 40 |
Carry an explicit battery assumption.
1,000 Wh nominal × 90% assumed usable share × (1 − 20% reserve) = 720 Wh before conversion. At 90% assumed inverter efficiency and no DC/standby load, that is 648 Wh delivered AC: 2.25 equivalent load-days at this daily energy use.
The saved runtime exercise uses daily Wh ÷ 24 as a constant average AC load. That average does not reproduce an appliance schedule, actual outage window or starting surge. Temperature retention is assumed 100%; output ratings, degradation, charging, actual weather and compatibility are unresolved.
Questions this exercise does not settle
- What are the exact starting/continuous ratings and documented energy boundary?
- Can the selected equipment operate together in the intended configuration?
- What seasonal production, cloudy sequences and charging limits apply at the actual location?
- What protection, mounting, permits, utility conditions and professional design checks are required?
Bring resource and cost assumptions back in.
For a simple solar exercise, two 450 W panels × four assumed equivalent-sun hours × 80% retained energy yield 2,880 Wh/day. That fictional day does not guarantee either project’s recharge. Use the dated production model for an actual location and keep tariff/ownership assumptions separate.
Sources & learning scope
Source concepts reviewed 2026-11-07. Exercise values are explicitly illustrative. This path explains concepts and arithmetic; it is not an installation design or professional certification.
- EIA: measuring electricity
Power, energy, W/kW and Wh/kWh.
- Australian Government: battery technology
Capacity, usable energy, output and backup configuration only; Australian program and installation rules are not applied here.
- DOE: photovoltaic system design basics
Modules, mounting, inverters and storage are separate system components.