Primary cells & rechargeable batteries · discharge analysis

Battery life & voltage profiles

Build a load schedule, specify the battery model, and explore terminal voltage, remaining charge and temperature. Datasheet identities and ratings are kept separate from simulation assumptions.

1. Choose a battery reference

BrandChemistryCell / battery formatManufacturer reference

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A product entry is not a complete validated model. A loaded discharge curve is not an open-circuit voltage curve; a 1 kHz impedance rating is not DC resistance. Unknown fields remain blank.

2. Define the cell or battery unit

Illustrative model: editable assumptions, not a manufacturer fit.

Reference capacity per unit (Ah) Effective DC resistance per unit (Ω) Cutoff per unit (V) Units in series Parallel strings Initial reference SOC (%) Accessible SOC reserve (%) Capacity state of health (%) Constant-power converter efficiency (%) Self-discharge (% of remaining charge/day) Per-unit discharge-current limit (A, optional) Default battery temperature (°C)

One “unit” may be a cell or a documented monobloc. For a 12 V lead-acid block, use block-level voltage, capacity and resistance consistently. Units are identical; mismatch and BMS behavior are not modeled. SOH is supplied capacity scaling, not an aging forecast.

Relaxed OCV curve: SOC %, voltage VSorted SOC from 0 to 100; nondecreasing voltage. Enter measured or documented relaxed OCV data.Temperature curve: °C, capacity factor, R factorNo extrapolation. Capacity factors are relative to the reference capacity and must be in (0,1]. Use a capacity reference that bounds the modeled temperatures.

Documented temperature scenario

This action replaces capacity, cutoff and temperature points with the reference’s stated test conditions. Resistance factors remain a declared constant assumption unless you supply data.

Manufacturer discharge-curve reference

This explicitly estimates OCV ≈ loaded test voltage + test current × your entered effective DC resistance. It is a reference-curve screening scenario at the reference conditions, not a measured relaxed-OCV curve or a qualified prediction at other loads.

Model / measurement provenance

3. Apply loads and temperatures

The rows run in sequence and repeat until service ends or the calculation horizon is reached. Each row holds its load and optional battery temperature constant. Use multiple rows for pulses, duty cycles and temperature changes.

seconds, load type, value, optional battery °C

Type	Value	Connection / meaning
current	A	Current at pack terminals; efficiency is not applied again.
power	W	Useful output power; the entered converter efficiency increases battery draw.
resistance	Ω	Resistor directly across the pack. Voltage and current are solved together.

Calculation horizon (hours)Maximum integration step (seconds)

Runtime & load service

Calculate to see the model result.

Plot

Hover or touch the plot to inspect a calculated point.

Points are an adaptively sampled numerical trace, not laboratory measurements. Load and temperature transitions can produce real model discontinuities.

Model equations, interpretation & limits

OCV is interpolated against accessible SOC. Pack resistance is Runit × series / parallel, and terminal voltage is Voc − I·R. Constant-power loads solve P/η = I(Voc − IR) on the low-current branch; an infeasible load ends service even if charge remains.

Reference charge is conserved across temperature changes. For a capacity factor f, the inaccessible lower charge window is Qref(1−f), and accessible SOC = (remaining reference charge − inaccessible window)/(Qref·f). Warming can make retained charge accessible; it does not create charge. This screening model needs a temperature curve appropriate to the actual cell, load and cutoff.

The model stops at the first cutoff, reserve, temperature-capacity, current or power constraint. Horizon/step-limited runs give a lower bound, not a predicted full lifetime. Very short pulses repeated over years may need a longer step budget or a separately justified averaged model.

Discharge only. No charge protocol, cycle-life prediction, Peukert/rate-capacity behavior, relaxation, hysteresis, transient polarization, self-heating, cell mismatch or protection dynamics. Fixed OCV/resistance and temperature factors do not establish accuracy across every current, chemistry or temperature. Primary cells must not be treated as rechargeable.

For a simple average-current calculation, use the separate Battery Runtime Arithmetic tool. Manufacturer operating limits and current limits remain separate from this model.