Battery Pack Series/Parallel Configurator mechanism

Model scope

The core series/parallel arithmetic is standard and correct under the stated ideal assumptions. The specification needs an explicit voltage convention (nominal, maximum, or operating range), explicit validation constraints for S and P, and either removal of the optional weight output or a defined weight formula and required inputs.

• Vpack=S·Vcell, Cpack=P·Ccell, and Wh=Vpack·Cpack are correct for identical cells in an ideal SxP arrangement.
• The formulas do not account for voltage sag, usable-depth-of-discharge limits, charge/discharge efficiency, cell mismatch, wiring losses, or BMS limits; outputs are therefore nominal/theoretical values.
• The listed optional weight estimate has no formula, cell-mass input, enclosure-mass input, or definition of whether it is an estimate or a measured result.

Units and conventions

• Vcell is in volts (V), Ccell is in ampere-hours (Ah), and Wh is watt-hours.
• Vcell and Ccell are nominal cell ratings; Wh is nominal stored energy, not guaranteed usable energy.
• S and P are positive integer counts: S is the number of cells in series and P is the number of parallel strings.
• Cells in every series and parallel position are assumed identical and connected in a conventional SxP topology.
• If capacity is supplied in mAh, it must be divided by 1000 before applying Cpack=P·Ccell; for example, 2500 mAh=2.5 Ah.
• The spec does not explicitly state nominal versus maximum/minimum cell voltage, so the voltage interpretation is ambiguous.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "cell_voltage_V": 3.7,
    "cell_capacity_Ah": 2.5,
    "S": 3,
    "P": 4
  },
  "expected_outputs": {
    "pack_voltage_V": 11.1,
    "pack_capacity_Ah": 10,
    "pack_energy_Wh": 111
  },
  "working": "Vpack=S·Vcell=3·3.7=11.1 V. Cpack=P·Ccell=4·2.5=10 Ah. Wh=Vpack·Cpack=11.1·10=111 Wh."
}

Failure boundary

• Reject S<=0 or P<=0; zero or negative counts are physically invalid and can produce zero or nonsensical pack ratings.
• Require S and P to be integers; fractional cell counts are invalid.
• Reject missing, nonnumeric, zero, or negative cell voltage and capacity inputs.
• Avoid division by zero in any future reverse-calculation feature when deriving S, P, or cell values.
• Prevent accidental mixing of mAh and Ah; silently treating 2500 mAh as 2500 Ah creates a 1000-fold capacity and energy error.
• A pack's actual usable energy is lower or different than nominal Wh depending on cutoff voltage, load, temperature, aging, and efficiency.
• A weight output without a defined model must not be presented as an authoritative result.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• evidence-tranche4/tranche4-results.json