FA-12301 / Battery state accounting / Open access

Series availability sums incompatible cell inventories · case 01

Series discharge is allowed to draw the sum of individual cell inventories.

Verified by executionVariant 1 · 6 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

Series discharge is allowed to draw the sum of individual cell inventories.

THE FAILURE

Series discharge is allowed to draw the sum of individual cell inventories.

Unsuccessful approach: Using the average still overdraws the smallest cell.

Case contract

For a nonempty list of nonnegative cell charge inventories and nonnegative request, return delivered charge and remaining cells; series cells each supply the delivered amount.

Why this case matters

An explicit synthetic battery bookkeeping model isolates this state-accounting error; it is not an engineering prediction or safety procedure.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(cells, request):
    d = min(request, sum(cells))
    return [d, [c-d for c in cells]]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('unequal', solve([2*N,8*N], 5*N), [2*N,[0,6*N]])
check('empty cell', solve([0,8*N], N), [0,[0,8*N]])
check('equal', solve([4*N,4*N], 3*N), [3*N,[N,N]])
check('single', solve([4*N], 8*N), [4*N,[0]])
check('no request', solve([2*N,8*N], 0), [0,[2*N,8*N]])
check('three cells', solve([9*N,3*N,7*N], 8*N), [3*N,[6*N,0,4*N]])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
unequal	`[5, [-3, 3]]`	`[2, [0, 6]]`	Failed
empty cell	`[1, [-1, 7]]`	`[0, [0, 8]]`	Failed
equal	`[3, [1, 1]]`	`[3, [1, 1]]`	Passed
single	`[4, [0]]`	`[4, [0]]`	Passed
no request	`[0, [2, 8]]`	`[0, [2, 8]]`	Passed
three cells	`[8, [1, -5, -1]]`	`[3, [6, 0, 4]]`	Failed

SHA-256 / d9fe7dd5baff55b5c0cd725af0c05a5951b625ab7f1ce89d9958dda60289f106

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(cells, request):
    d = min(request, sum(cells)//len(cells))
    return [d, [c-d for c in cells]]
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
check('unequal', solve([2*N,8*N], 5*N), [2*N,[0,6*N]])
check('empty cell', solve([0,8*N], N), [0,[0,8*N]])
check('equal', solve([4*N,4*N], 3*N), [3*N,[N,N]])
check('single', solve([4*N], 8*N), [4*N,[0]])
check('no request', solve([2*N,8*N], 0), [0,[2*N,8*N]])
check('three cells', solve([9*N,3*N,7*N], 8*N), [3*N,[6*N,0,4*N]])
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
unequal	`[5, [-3, 3]]`	`[2, [0, 6]]`	Failed
empty cell	`[1, [-1, 7]]`	`[0, [0, 8]]`	Failed
equal	`[3, [1, 1]]`	`[3, [1, 1]]`	Passed
single	`[4, [0]]`	`[4, [0]]`	Passed
no request	`[0, [2, 8]]`	`[0, [2, 8]]`	Passed
three cells	`[6, [3, -3, 1]]`	`[3, [6, 0, 4]]`	Failed

SHA-256 / 908e1a07649466efe7e32b179694b08d31b27a279243adf28249ffe6bdee245c

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 6 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

Member access is invitation-based. Sign in with your invited account to inspect the repair.

Verification & scope

Integer toy accounting with declared loss rules; no electrochemistry, hardware behavior, or safety claims. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:55.595315+00:00.

Case digest / 341036a84dc2a091b49a5600c9159a9f86e04c8dcb68628c93167c85243efd6a