English
For the design of battery storage with the requirement to back up at least the minimum required part of the house installation for the required time, the following table shows a possible method of calculation.
To design the system, we need both the required battery capacity in kWh and the maximum instantaneous power of the system (inverter) to ensure a reliable backup function.
Individual appliances, their power consumption and running time are usually estimated, so it is advisable to take into account a certain margin.
| Appliance | Power consumption during operation | Estimated running time in 24 hours | Estimated consumption in 24 hours |
| Fridge | 100 W | 8 | 0,8 kWh |
| Router Wifi, AP internet | 15 W | 24 | 0,4 kWh |
| Gas boiler (in the heating season) | 140 W | 12 | 1,7 kWh |
| Desktop PC | 150 W | 1 | 0,2 kWh |
| Radio | 20 W | 6 | 0,1 kWh |
| TV LED | 45 W | 2 | 0,1 kWh |
| Lighting (summer season) | 120 W | 3 | 0,4 kWh |
| Lighting (winter season) | 120 W | 7 | 0,8 kWh |
| EZS, cameras | 50 W | 24 | 1,2 kWh |
| Control system | 50 W | 24 | 1,2 kWh |
| Immediate consumption (summer season) | 550 W | ||
| Immediate collection (winter season) | 690 W | ||
| Total (summer season) | 4,3 kWh | ||
| Total (winter season) | 6,4 kWh |
It can be seen from the table that for the summer period, respectively. if we do not consider backing up the heating system, we also do not consider DHW heating and cooling, for the given example the calculation is based on a battery capacity of 4.3 kWh, if we assume discharge to about 20 % of capacity, then a 5 kWh battery would be suitable for this purpose.
Typical inverter power values of around 2000 VA would be suitable for this purpose without any problems.