Battery size is where many solar projects fail. People either buy too little or buy far too much. Both decisions waste money. The correct battery size is determined by your daily electricity consumption. Nothing else first. What Does Battery Size Mean? Solar battery size refers to the amount of energy a battery can store. Manufacturers commonly use:
- Amp-hours (Ah)
- Kilowatt-hours (kWh)
Modern systems increasingly use kilowatt-hours because they provide a clearer picture of usable energy.
Common Solar Battery Sizes
100Ah Batteries
Suitable for:
- Lighting
- Television
- Internet routers
- Phone charging
Ideal for emergency backup systems.
200Ah Batteries
Suitable for:
- Small homes
- Refrigerators
- Lighting
- Entertainment systems
5kWh Batteries
Suitable for:
- Average family homes
- Daily solar usage
- Moderate appliance consumption
10kWh Batteries
Suitable for:
Heavy evening usage
Large homes
Water pumps
Security systems
How To Calculate The Right Battery Size
Step 1: List your appliances.
Step 2: Calculate daily energy consumption.
Step 3: Determine how many hours of backup you need.
Step 4: Add a safety margin.
For example:
| Appliance | Power Consumption | Daily Hours | Daily Usage |
| TV | 100W | 5 | 500Wh |
| Refrigerator | 150W | 10 | 1,500Wh |
| WiFi Router | 20W | 24 | 480Wh |
| Lights | 100W | 6 | 600Wh |
Total daily usage: 3,080Wh or 3.08kWh. A 5kWh battery comfortably supports this scenario.
The Biggest Sizing Mistake
People buy batteries based on neighbour recommendations. Every home consumes electricity differently. Your battery should reflect your lifestyle, not someone else’s system. Battery sizing is mathematics. Guesswork becomes expensive very quickly.
