Stationary battery capacity sizing per IEEE Std 485 methodology — lead-acid, Li-ion and LFP
Dwg No.BAT-001
ScaleNTS
MethodIEEE 485
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Preliminary sizing only.This tool applies the IEEE Std 485 correction-factor approach (temperature × aging × design margin) to produce an initial capacity estimate. It does not replace the manufacturer's published discharge-rate tables, which are what actually determine whether a specific cell meets a specific duty cycle at a specific end-of-discharge voltage. Final selection must be verified against the battery manufacturer's data and reviewed by a qualified engineer.
1
SystemTag, DC bus voltage, chemistry
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Cell voltage auto-fills from the chemistry (2 V lead-acid, 1.2 V Ni-Cd, 3.7 V NMC, 3.2 V LFP) but can be overridden — enter the actual cell/module you intend to use from the manufacturer's catalogue.
2
Load ProfileSingle load, or a multi-period duty cycle
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Add one period for a simple constant load, or several to build a duty cycle (e.g. a large inrush for the first minute, then a lower continuous load). Watt-based loads are converted to amps at the nominal bus voltage — a conservative simplification, since real constant-power loads draw more current as the battery voltage falls.
3
Correction FactorsIEEE 485: temperature × aging × design margin
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IEEE 485 uses an aging factor of 1.25 (sizing so the bank still meets load at 80% end-of-life capacity) and a design margin of typically 1.10–1.15 for future load growth. Set efficiency below 1.00 only if the load figure entered is on the AC side of an inverter.
Result — Required Bank
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Required capacity (Ah)
Uncorrected demand
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Cumulative correction
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Cells in series
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Strings in parallel
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Total cells / modules
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Installed energy
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Bank Configuration
series × parallel arrangement
Calculation Ledger
IEEE 485 correction-factor method
Manufacturer Catalogues
verify final selection against published discharge tables