Battery runtime with own assumptions
Capacity, usable depth, remaining-capacity factor and conversion efficiency are your assumptions.
- Runs in your browser
- No upload
- Check before download
Capacity, usable depth, remaining-capacity factor and conversion efficiency are your assumptions. Constant power/current uses stated fixed voltage; Ah and Wh normalize accordingly. No Peukert exponent guessed, discharge curve, cutoff, temperature/aging or safety prediction.
Model, grammar and limits
Wh=Ah·V; t=Wh·DOD·derating·η/P; P=I·V
Numbers can have up to 48 characters, with a decimal point or scientific e, and no thousands separators. Voltage is generally 60 V or less; the 555 timer accepts 4.5 to 16 V. R is 1e−9 to 1e12 Ω (555: 1 to 1e9), C is 1e−18 to 100 F (555: at least 1 pF), and L is 1e−12 to 1e6 H. Curves use 2 to 501 samples, plus up to 502 cutoff and resonance points. Networks have up to 32 nodes and depth 8, with positive R only. Boolean expressions take 2 to 6 variables, 4096 characters, 1024 tokens, 512 AST nodes, depth 32, 64 rows, 729 cubes and 200000 search nodes; up to 16 ties are shown. LEDs: 1 to 100. Wire current: up to 1000 A, with your own linear temperature from −100 to 500 °C. These numeric bounds never certify that a design is physically suitable.
Values are converted to SI units and use explicit circuit layouts and ideal models. Results show up to 10 significant digits; CSV keeps the numeric values and units. A Boolean minimum is exact only when the bounded search finishes and all required (non-don't-care) rows check out. CODATA 2022 μ0 and ε0 are rounded measured constants with an uncertainty, not exact definitions; c = 299792458 m/s is exact. Nothing here is an approval for hardware, critical systems, installations or production.
Everything runs in a local worker with a 15-second time limit. Editing, resetting, canceling or leaving the page stops pending work. Inputs are never saved or uploaded automatically. An input backup is only made when you ask, up to 1 MiB, and your original files stay untouched. Input data, formulas and filenames are never sent. Only with your optional consent, Refentra sends aggregate counts of actions and outcomes, without input content.
Use this model
- Own inputs
Choose Ah or Wh capacity and a fixed voltage. Select constant power or constant current, and enter the usable depth, the remaining-capacity factor and the efficiency as percentages.
- Model, grammar and limits
Example: 10 Ah × 12 V = 120 Wh. With usable 80%, remaining 100%, efficiency 90% and a load of 24 W, you get 86.4 Wh and 3.6 h.
- Download CSV report
Compare the nominal and available Wh before you look at the runtime. Save the report with your assumptions, then check them against the real battery and load specifications.
Questions and model limits
What does this result mean?
Ah is charge capacity, and Wh is energy at the voltage you supply. At a fixed voltage, a current load becomes power through W = V × A.
How do I resolve rejected or missing input?
Use decimal points and the matching unit. A factor of zero can give a runtime of zero, and the load and voltage must be positive. Correct any fields that are rejected before you recalculate.
What are the limits of this tool?
This is a constant-load model. It is not a discharge curve, a battery-health test or a safety prediction. Voltage sag, temperature and a varying load need separate evidence.