Path-Q Solar
How should battery power output be sized separately from battery energy capacity?
Answer
Size battery power output for the largest instantaneous or sustained load the battery must serve, and size energy capacity for how long those loads must run. A battery can have ample kWh but insufficient kW to start or operate high-power equipment, or high kW capability but too little stored energy for the desired duration.
Key points
- List critical loads and their starting, running, and continuous power requirements.
- Calculate required duration in kWh after accounting for usable capacity and losses.
- Decide whether the battery must serve all loads, selected backup loads, or only load shifting.
What it depends on
- Peak and continuous load power
- Motor-starting or surge requirements
- Required backup duration
- Usable battery capacity and reserve
- Inverter power rating and operating limits
Risks and trade-offs
- Sizing only by kWh may cause overloads or prevent high-power appliances from operating.
- Sizing only by kW may provide little runtime.
- Supporting large intermittent loads can require more inverter and battery capability than their annual energy use suggests.
Information you may need
- Critical-load list
- Running and startup power for major equipment
- Desired runtime and outage scenarios
- Battery usable kWh and continuous and surge kW
- Inverter operating limits and control strategy
Your next step
What to do next
Create a load schedule with running kW, startup kW, and required hours, then request a battery design that reports power and energy sizing separately.
Path-Q
Find the right next step
Answer a few questions and we’ll narrow your options.
Loading…
SQ02429