1. Determine Your Daily Energy Consumption (kWh/day)
The first step in sizing any solar system is understanding how much electricity your home actually uses.
How to calculate it:
According to solar engineering guidance, begin by listing all appliances, noting:
- Power rating (W) × hours used per day = Wh/day for each device
- Add all appliance consumption to get total daily energy demand
You can also use your utility bill:
- Monthly kWh ÷ 30 = daily kWh consumption (supported by residential sizing guides)
Typical South African household ranges:
- Small households: 10–15 kWh/day
- Average homes: 20–30 kWh/day
- Large homes: 30–50+ kWh/day
This number will drive PV array size, battery storage, and inverter rating.
2. Choosing the Correct Inverter Size
What the inverter does:
It converts the DC power from your solar array to usable AC electricity. Proper inverter sizing ensures efficiency, safety, and long-term reliability.
How to size your inverter:
Rule of Thumb from global inverter standards:
Choose an inverter 25–30% larger than your maximum connected load to handle continuous consumption and appliance surge currents.
Another critical insight from inverter engineering literature:
- Size the inverter based on the solar array capacity, not the home’s energy demand.
- A DC-to-AC ratio between 1.2 and 1.3 is often optimal.
Example:
If your total load is 5 kW, choose an inverter between 6–6.5 kW.
H.E.A Package Reference:
- Signal Hill Package → 8 kW hybrid inverter (ideal for smaller homes)
- Lions Head Package → 8 kW Plus hybrid inverter (medium homes)
- Cederberg Package → Dual 8 kW Plus hybrid inverters (16 kW total for large homes)
-
Drakensberg Package → 24 kW hybrid inverter capacity for high-demand households and estates
3. How to Size the PV Array (Solar Panels)
PV sizing depends on daily consumption and average peak sun hours in your area.
Step-by-step calculation:
- Daily kWh demand ÷ peak sun hours = required PV kW
- Add 20–30% overhead to compensate for:
- Temperature losses
- Shading
- Dust
- Inverter inefficiency
(This approach is supported by practical solar design guidance.)
Example:
If your home uses 25 kWh/day and your region has 5 sun hours/day:
- 25 ÷ 5 = 5 kW base
- Add 25% losses → 6.25 kW recommended array
H.E.A PV Sizes for Comparison:
- Signal Hill: 7.26 kWp (entry-level)
- Lions Head: 10.89 kWp (medium homes)
- Table Mountain & Cederberg: 14.52 kWp (large homes)
- Blyde Canyon: 19.36 kWp
-
Drakensberg: 36.67 kWp (commercial/estate-scale)
4. How to Size Your Battery Storage (kWh)
Battery sizing determines how long you can operate during load‑shedding or without sunlight.
Battery sizing formula (industry standard):
- Decide how many hours of backup you need.
- Multiply daily consumption × percentage of home you want to power.
- Choose a battery with ≥ 90% depth of discharge for maximum usable capacity (supported by modern lithium-ion guidelines).
Examples:
- Essential loads only (lights, WiFi, fridge): 5–10 kWh
- Whole home evening usage: 15–20 kWh
- Full autonomy / estates: 30–50 kWh
H.E.A Battery Reference Sizes:
H.E.A offers 10kWh, 16kWh, 20kWh, 40kWh and 50kWh LiFePO₄ batteries, ideal for:
- Small homes → 10–16 kWh
- Medium homes → 20–32 kWh
- Larger homes → 40–50 kWh
5. Matching System Components Using H.E.A Installed Packages
Below is a practical mapping to help customers choose confidently.
Signal Hill Package (Entry Level)
- 8 kW inverter
- 7.26 kWp PV
- 10 kWh storage
Best for: Small households with 10–15 kWh/day usage
Lions Head Package (Medium-Sized Home)
- 8 kW Plus inverter
- 10.89 kWp PV
- 16 kWh storage
Typical Usage: 15–25 kWh/day
Table Mountain Package (Large Home)
- 8 kW Plus inverter
- 14.52 kWp PV
- 20 kWh storage
Typical Usage: 25–35 kWh/day
Cederberg Package (High-Demand Home / Small Business)
- 16 kW inverter (dual hybrid)
- 14.52 kWp PV
- 32 kWh lithium storage
Typical Usage: 30–50 kWh/day
Drakensberg Package (Estate / Commercial Level)
- 24 kW hybrid inverter configuration
- 36.67 kWp PV
- Up to 50 kWh storage
Usage: 50–100+ kWh/day
6. Summary Table (Simplified Quick Guide)
| Home Type | Daily Use | Suggested Inverter | PV Size | Battery Storage | H.E.A Package |
|---|---|---|---|---|---|
| Small | 10–15 kWh/day | 5–8 kW | 5–8 kWp | 10–16 kWh | Signal Hill |
| Medium | 15–25 kWh/day | 8 kW Plus | 10–12 kWp | 16–20 kWh | Lions Head |
| Large | 25–35 kWh/day | 8–16 kW | 14–16 kWp | 20–32 kWh | Table Mountain / Cederberg |
| Estate / Commercial | 50–100 kWh/day | 24 kW+ | 20–36 kWp | 40–50 kWh | Drakensberg |
7. Final Guidance
To size your system correctly in South Africa, always:
- Start with your daily consumption.
- Choose an inverter that can handle both continuous and surge loads.
- Size your PV array based on sun hours and losses.
- Choose a battery that supports your independence goals.
- Use packaged, certified solutions like H.E.A’s lineup for guaranteed performance.