Use this free calculator to plan required ah for a desired backup time. Change the load, starting surge, losses and battery limits to match your equipment.
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Every input includes a simple explanation.
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Motors and compressors can need extra power when they start.
Battery age, temperature and a high discharge rate can reduce delivered energy.
Use this as a planning range. Confirm continuous rating, peak rating and battery compatibility with the manufacturer and a qualified installer.
The required Ah works backward from load and desired hours while making discharge and conversion losses explicit.
Confirm whether batteries are arranged in series or parallel and choose a compatible standard capacity above the planning result.
Adding Ah for batteries connected in series is incorrect; series raises voltage while the string Ah remains unchanged.
Required Ah = load × hours ÷ (voltage × batteries × DoD × efficiency)
Confirm whether batteries are arranged in series or parallel and choose a compatible standard capacity above the planning result.
Adding Ah for batteries connected in series is incorrect; series raises voltage while the string Ah remains unchanged.
Use this as a planning range. Confirm continuous rating, peak rating and battery compatibility with the manufacturer and a qualified installer.