How do I choose energy storage?
Capacity is only one system characteristic.
Energy capacity and power
kWh describes stored energy, while kW describes the power that can be supplied or accepted. For example, a high-capacity battery cannot necessarily power high-demand loads simultaneously.
What should I ask before buying?
- What is the usable capacity, rather than just nominal capacity?
- What charging and discharging power is permitted?
- What temperature and installation location conditions apply?
- Can it be expanded later, and under what conditions?
- Is the battery compatible with a specific inverter?
Backup power
Treat it as a function of the whole system. The inverter, switching, loads, battery power and designed grid isolation all matter.
Battery manufacturers and ranges · Compatibility explained.
How many kWh do you need in the evening?
Start with the electricity you want to shift from daytime to evening and night. Usable battery capacity differs from nominal capacity; reserve and losses may account for part of the energy. Annual kWh consumption alone does not show evening needs.
10 kWh of usable energy divided by a constant 0,5 kW load would theoretically last 20 hours. This arithmetic example excludes additional losses and does not promise a specific battery runtime. Peak demand must also stay within the battery and inverter power limits.
What matters beyond the price per kWh?
Compare controllers, modules, cables, protective devices, installation and warranties on a like-for-like basis. Agree in advance whether storage is for self-consumption, tariff differences, backup or several purposes. Each purpose can change usable capacity and control modes.
If grid export is limited, assess self-consumption and the 1 kW limit. Instructions for specific systems are available in in the document library.