Battery Charge Time Estimator mechanism

Model scope

The core arithmetic is appropriate for a rough CC estimate, but the specification needs explicit unit conventions and an explicit percentage-to-fraction conversion before implementation. The verdict is NEEDS_REVIEW because those ambiguities can materially change the output.

• The formula is standard for a rough constant-current estimate only when efficiency is a dimensionless fraction. Because the input is specified as efficiency %, the implementation must convert it as efficiency_fraction = efficiency_percent / 100; using the percentage value directly produces a 100-fold error.
• The formula does not explicitly define capacity and charger-current units, so the result unit is ambiguous unless capacity is in Ah and current is in A, or equivalent units are consistently used.
• The CC-CV taper is mentioned but not modeled; therefore the result is not a full battery charge-time calculation and will generally underestimate actual time.

Units and conventions

• Capacity is in ampere-hours (Ah) and charger current is in amperes (A), producing time in hours.
• Capacity and current may use other matching prefixes, such as mAh and mA, because their ratio remains in hours; mixed units require conversion first.
• Efficiency input is a percentage from greater than 0% through 100%, converted to a fraction by dividing by 100.
• The charger current is treated as a constant effective current during the modeled charging interval.

Inspectable vector

One of 4 source-bound review vectors:

{
  "inputs": {
    "capacity_Ah": 2.4,
    "charge_current_A": 1.5,
    "efficiency_percent": 90
  },
  "expected_outputs": {
    "estimated_charge_time_hours": 1.77777778
  },
  "working": "efficiency_fraction = 90 / 100 = 0.90; base_time = 2.4 Ah / 1.5 A = 1.6 h; estimated_time = 1.6 h × (1 / 0.90) = 1.6 / 0.90 = 1.77777778 h."
}

Failure boundary

BREAK_CLAIMED · SELF_FLAGGED

A zero charging current produces an undefined division-by-zero result, and the CC-CV note describes a second regime without supplying a CV taper formula or data needed to calculate it. Negative-current handling is also unspecified and can produce a nonsensical negative time if applied literally.

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
• BOUNDARY_HAZARD_CATALOG.json