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Battery Explorer

Offline · No tracking · Shepherd + Peukert
Model disclaimer: Curves are generated by the Modified Shepherd voltage model and Peukert's Law applied to an averaged generic alkaline cell capacity tier. These are mathematical approximations for ballpark estimation only and do not represent any specific manufacturer's cell or datasheet. Real cells vary with batch, age, storage, temperature, and duty cycle.

Configuration

Results

Pack voltage
1.50 V
Per-cell current
100 mA
Temp factor
1.00×
Peukert-effective cap
2660 mAh
Estimated runtime
26.6 h

How to read these charts

Discharge curve — voltage vs. how much capacity you've pulled out. Each colored line is a fixed current; the bold emerald line is your configured draw. It shows how the pack's voltage sags down to the cutoff as it empties at that current.

Runtime curve — how many hours the pack lasts vs. the current you pull (log–log). The ★ operating point is your configured draw; the dashed line drops to the current axis.

Example: at 500 mA the runtime curve might read ~30 h, but doubling the draw to 1 A drops it well below half — that bend is Peukert's law: pulling harder wastes capacity.

Discharge curve — Modified Shepherd

Thin colored curves are fixed reference currents; the bold emerald curve tracks your configured per-cell draw. Hover the plot for live values.

Runtime curve — Peukert (log–log)

Star = operating condition; dashed projection drops to the current axis. Hover the plot for live values.
Why a pack browns out while it still reads "good": under load the terminal voltage drops by I×R (internal resistance). A regulated product behaves like a constant-power load, so as voltage sags it pulls more current, deepening the sag. When loaded voltage falls below the unit's cutoff it shuts down — often with most of the pack's energy still unused. Enter a bench measurement to characterize your unit.

Load & pack

Per-level results

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What "operating point" means & how to read these

A battery and a device have to agree on one voltage and current. The battery can only hand over a voltage that sags as you draw more current (the cyan source line). Your device demands a fixed power, so as the voltage sags it pulls more current (each colored load curve). The single point where a load curve crosses the source line is the only place the system can settle — that's the operating point, marked with a ★.

Load-line chart: follow a colored load curve to where it crosses the cyan line. If the ★ is above the red cutoff, that load runs; if the curve never reaches the source line, there's no ★ and the pack collapses under it.

Brown-down chart: each colored line is the loaded voltage as the pack drains (left → right). Where a line crosses the red cutoff is the % discharged at which that load browns out. The cyan no-load line above it shows how much voltage the load is costing you.

Example (defaults): a 12 V pack with R = 1 Ω, so the source line is V = 12 − I. Take Load2 = 20 W: the load needs 20/V, and setting 12 − I = 20/I gives I² − 12I + 20 = 0 → I = 2 A, V = 10 V (its ★), well above the 6 V cutoff. The four defaults (11/20/27/32 W) land on exactly 11/10/9/8 V at 1/2/3/4 A. The pack's ceiling is V²/4R = 36 W; push any load past that and its ★ vanishes — collapse.

Load line — battery source vs constant-power load

The source line droops with current (slope = pack resistance); the load curve is the unit's constant-power demand. Their crossing is the operating point — if it sits below the red cutoff line, the unit browns out.

Loaded voltage as the pack drains

Cyan = resting (no-load) pack voltage; emerald = voltage under your load. Where emerald crosses the red cutoff is brownout — capacity to the right of that point is stranded.