Public evidence

electrical.battery.pack_sizing

Machine-checked verification for calculation version 1.2.0 · tier internally_reviewed

Open calculator API Capability Download JSON CVP Manifest MCP Review policy

CVP: CVP VERIFIED · CVP protocol 1.0.0-proposed · Engineering assurance· Planning estimate — not BMS / chemistry pack design · Protocol · Schema · Production report

Declared partition coverage: PASS · 4/4 declared partitions (watts, amps, cells, invalid-domain)
Versions: Calculation 1.2.0 · CVP protocol 1.0.0-proposed · Evidence 2026-09-12.round-xcal-iface
Verification revision: 2026-09-12.round-xcal-iface · 7/7 property · digest 1e3949ba3d8e

Verification

Legacy regression suite: 27/27 calculation tests · Production surface contract 4/4

Three distinct suites: educational examples on the calculator page, this legacy regression count (27/27 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.2.0 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-09-12.round-xcal-iface. Calculation version 1.2.0. CVP 1.0.0-proposed. 3/3 golden · 16/16 CVP boundary · 14/14 invalid · 7/7 property · 2/2 round-trip · 3/3 cross-interface · 2/2 cross-calculator · 4/4 CVP contract. digest 1e3949ba3d8e.

Golden (oracle-backed) 3 / 3
CVP boundary 16 / 16
Invalid input 14 / 14
Property 7 / 7
Round-trip 2 / 2
Cross-interface 3 / 3
Cross-calculator 2 / 2
CVP contract 4 / 4
Interfaces PASS · UI (SSR) / REST / MCP
Interface claim ui-ssr is query-result HTML, not a live browser session.
Assurance Engineering

release artifacts aligned PASS
schema valid input executes PASS
engine success output validates schema PASS
schema rejects incomplete input PASS

Fingerprint sha256:b3a87a18a21fe41a5c7d2da0d313bf40be7ccbbf30980df5749b8ea96dbd34ca

Input schema sha256:efbfe6f1c002ef9ba44af12ce224324e0618ece83cfc78c98f4db8b38c5f70f3 · Output schema sha256:acb2f259f709c99aca6f4aac55846212b216b63f875beae2644fd0d8aecde756 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Build & scope

Engine identity and declared limitations.

Tool: battery-pack-sizing
Engine: battery-pack-sizing
Engine build: 2026-09-10
Evidence core: 2026-09-05T15:29:50.831Z
Rendered: 2026-09-16T22:03:43.720Z
Last reviewed: 2026-09-05

Assumptions

Constant load; ceil cell counts as nominal packing estimate; not Peukert or BMS design
Amps mode I_A is battery-side; η does not enter Ah
V is target/system nominal voltage; V_pack = Ns·V_cell may differ

Limitations

Constant-load inverse of BatteryRuntimeBaseInput / battery_runtime 1.2+
Amps mode = battery-side current; η does not enter Ah
Cell Ns/Np use ceil — nominal packing estimate only, not BMS / chemistry pack design
When V_pack ≠ V_target the result includes warning PACK_VOLTAGE_DIFFERS_FROM_TARGET
mode=watts requires P_W; mode=amps requires I_A
V_cell XOR incomplete pair → NEEDS_TWO_INPUTS (both or neither)

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

IEC 60050 — International Electrotechnical Vocabulary — Electric battery capacity and related quantities
Supports: Ah capacity and Wh energy relationship E ≈ Q·V for nominal estimates
Victron Energy — Battery capacity and Peukert exponent — SmartShunt / battery monitor documentation
Supports: Ideal Ah ≈ I·t under constant current; Peukert and rate effects as reasons this tool stays first-order (Not Peukert)
CalculatorX Battery Runtime capability — Constant-load watts/amps model (1.2+) — internal method dependency
Supports: Inverse capacity sizing; shared watts/amps semantics with electrical.battery_runtime

Methods

Algorithms this engine uses. Not external references.

derived_from:electrical.battery_runtime@1.2.0 — inverse constant-load watts/amps model

Legacy published checks

Golden and boundary cases from the legacy Evidence JSON. CVP property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the Manifest — including SKIP when a suite has no vectors.

ID	Kind	Status	Detail
`ideal-10Ah`	golden	pass	Expected capacity_Ah=10 · E_Wh=120 · Actual mode=watts · capacity_Ah=10 · E_Wh=120 · t_h=6 · V=12 · dod=1 · eta=1 · P_W=20
`cells`	golden	pass	Expected capacity_Ah=10 · n_s=4 · n_p=4 · n_cells=16 · Actual mode=watts · capacity_Ah=10 · E_Wh=148 · t_h=5 · V=14.8 · dod=1 · eta=1 · P_W=29.6
`cell-half`	boundary	pass	Expected NEEDS_TWO_INPUTS · Actual NEEDS_TWO_INPUTS
`missing-t`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`amps-eta-ignored`	golden	pass	Expected capacity_Ah=10 · E_Wh=96 · Actual mode=amps · capacity_Ah=10 · E_Wh=96 · t_h=4 · V=12 · dod=0.8 · eta=1 · I_A=2
`nonintegral-series`	boundary	pass	warning PACK_VOLTAGE_DIFFERS_FROM_TARGET
`boundary-10Ah`	boundary	pass	Expected capacity_Ah=10 · E_Wh=120 · Actual mode=watts · capacity_Ah=10 · E_Wh=120 · t_h=6 · V=12 · dod=1 · eta=1 · P_W=20
`boundary-cells`	boundary	pass	Expected n_s=4 · n_p=4 · Actual mode=watts · capacity_Ah=10 · E_Wh=148 · t_h=5 · V=14.8 · dod=1 · eta=1 · P_W=29.6
`boundary-cell-capacity-only`	boundary	pass	Expected NEEDS_TWO_INPUTS · Actual NEEDS_TWO_INPUTS
`boundary-invalid-mode`	boundary	pass	Expected INVALID_MODE · Actual INVALID_MODE
`boundary-dod-over-one`	boundary	pass	Expected FRACTION_OUT_OF_RANGE · Actual FRACTION_OUT_OF_RANGE
`boundary-eta-zero`	boundary	pass	Expected FRACTION_OUT_OF_RANGE · Actual FRACTION_OUT_OF_RANGE
`boundary-t-zero`	boundary	pass	Expected VALUE_MUST_BE_POSITIVE · Actual VALUE_MUST_BE_POSITIVE
`boundary-V-zero`	boundary	pass	Expected VOLTAGE_MUST_BE_POSITIVE · Actual VOLTAGE_MUST_BE_POSITIVE
`boundary-P-zero`	boundary	pass	Expected LOAD_MUST_BE_POSITIVE · Actual LOAD_MUST_BE_POSITIVE
`boundary-I-zero`	boundary	pass	Expected LOAD_MUST_BE_POSITIVE · Actual LOAD_MUST_BE_POSITIVE
`boundary-dod-zero`	boundary	pass	Expected FRACTION_OUT_OF_RANGE · Actual FRACTION_OUT_OF_RANGE
`boundary-eta-over-one`	boundary	pass	Expected FRACTION_OUT_OF_RANGE · Actual FRACTION_OUT_OF_RANGE
`boundary-watts-missing-P`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`boundary-amps-missing-I`	boundary	pass	Expected MISSING_REQUIRED_INPUT · Actual MISSING_REQUIRED_INPUT
`property-ah`	property	pass	10 Ah
`property-load`	property	pass	2P → 2Ah
`property-cells`	property	pass	4S4P exact stack (no voltage-diff warning)
`property-amps-eta-ignored`	property	pass	amps η ignored
`property-pack-voltage-differs`	property	pass	12 V / 3.7 V → V_pack 14.8 + PACK_VOLTAGE_DIFFERS_FROM_TARGET
`property-roundtrip-runtime-watts`	property	pass	pack sizing ↔ battery_runtime watts round-trip
`property-roundtrip-runtime-amps`	property	pass	pack sizing ↔ battery_runtime amps round-trip