Start with a real-life situation
A 5 kWh battery does not necessarily run a 5 kW load for a full hour. Some capacity may remain reserved, conversion incurs losses, and continuous output has limits.
POWER × TIME = ENERGY
Preliminary calculation lab
Change power and time to explore energy demand and preliminary nominal storage.
E = P × t
C = E / (η × usable)Assumes steady load and no solar contribution during this period. Enter supported efficiency and usable-fraction data. Initial values are teaching examples. Surge power, ageing, temperature and additional reserve are not included.
1. Nominal and usable capacity
Calculate load energy first, then allow for usable fraction and total-path efficiency. A teaching example of 2 kW for 4 hours, 90% efficiency and 80% usable fraction needs about 11.11 kWh nominal capacity. This is not a final order size.
2. Power and operating conditions
Read continuous current/power, surge limits, operating temperature and installation conditions from the manufacturer. Ageing, temperature and reserve can change the selection. This tool exposes simple assumptions, not battery lifetime or guaranteed runtime.
3. Matching battery and inverter
Check operating voltage, allowed range, current, module count and official BMS compatibility lists. Firmware may matter too. For OAKEN products, obtain confirmation for the final model and version before ordering.
Check before deciding
- Usable energy and continuous power
- Model and firmware compatibility list
- Environment, installation and warranty
CHECK YOUR UNDERSTANDING
A quick knowledge check
Sources & scope
Named technical review has not yet been recorded.
Preliminary guidance. Structural, safety and construction approval requires the responsible engineer and final model documents.