diagnose-battery-charging-problem

diagnose-battery-charging-problem is a skill for Claude Code from jeffreytse/grimoire-core. It costs 47 tokens per session (1,401 once invoked), scanned A, original, MIT.

A step-by-step guide for finding the cause of vehicle starting or electrical charging problems. It covers the battery, alternator, and charging circuit.

In plain words
What is it for?
Use it to diagnose starting failures, battery warning lights, and other charging-system symptoms.
Why use it?
It reduces guesswork and helps avoid replacing a battery or alternator that is not actually faulty.

Skill for Claude Code

Written for Claude Code: shipped in a Claude Code plugin.

Part of the grimoire-automotive plugin — 16 skills shipped together

Good fit Use it to diagnose starting failures, battery warning lights, and other charging-system symptoms.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jeffreytse/grimoire-core/diagnose-battery-charging-problem
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add jeffreytse/grimoire-core --skill diagnose-battery-charging-problem
Clone the repo
git clone --depth 1 https://github.com/jeffreytse/grimoire-core

Made for: Claude Code.

Or install grimoire-automotive, the plugin that ships this one along with the rest of its 16 skills.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for diagnose-battery-charging-problem

README.md
[![agentmods](https://agentmods.dev/badge/skills/jeffreytse/grimoire-core/diagnose-battery-charging-problem/github.svg)](https://agentmods.dev/skills/jeffreytse/grimoire-core/diagnose-battery-charging-problem)
Your own site
<a href="https://agentmods.dev/skills/jeffreytse/grimoire-core/diagnose-battery-charging-problem"><img src="https://agentmods.dev/badge/skills/jeffreytse/grimoire-core/diagnose-battery-charging-problem/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for diagnose-battery-charging-problem

Your own site · 80×15
<a href="https://agentmods.dev/skills/jeffreytse/grimoire-core/diagnose-battery-charging-problem"><img src="https://agentmods.dev/badge/skills/jeffreytse/grimoire-core/diagnose-battery-charging-problem.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 47 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 1,401 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00047 $0.01401
Opus 5 $0.00023 $0.00700
Sonnet 5 $0.00009 $0.00280
Haiku 4.5 $0.00005 $0.00140

Measured 10d ago against content hash 426823c2b419, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-10, from the pricing page.

Security

Grade A, and why

diagnose-battery-charging-problem scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 10d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

skills/automotive/maintenance/skills/diagnose-battery-charging-problem/SKILL.md · 97 lines

How it starts

The opening of the file, as written. The whole thing — 97 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Diagnose Battery and Charging Problem

Systematically test the battery, alternator, and charging circuit to identify the root cause of starting failures or electrical problems — preventing unnecessary parts replacement by following a test-first diagnostic sequence.

Why This Is Best Practice

Why best: A fixed test sequence — battery load test before alternator test before parasitic-drain test — catches the actual fault instead of guessing, because each stage's result depends on the previous stage being confirmed good first. Adopted by: ASE (Automotive Service Excellence) certification requires systematic charging system diagnosis as part of A6 Electrical/Electronic Systems competency. All major auto repair chains (Firestone, Jiffy Lube, Midas) offer free battery and alternator testing as a standard service. OBD-II scan tools used by professional technicians prioritize charging system voltage codes as primary electrical diagnostics. Impact: The most common diagnosis error is replacing the battery when the alternator is the fault — or replacing the alternator when the battery (unable to hold a charge) is masking a good alternator. AAA data shows that battery-related calls represent ~20% of roadside assistance requests. A systematic test sequence takes 10–15 minutes and eliminates guesswork, preventing the second-most expensive diagnostic error in automotive service: replacing good parts.

Steps

1. Gather symptoms before testing

Document the presenting complaint:

  • Slow crank / click on start: battery, battery terminals, or starter
  • No crank (complete silence): battery, terminals, ignition switch, neutral safety switch
  • Engine starts, battery light illuminates: alternator or drive belt
  • Battery repeatedly dies overnight: parasitic drain or battery can't hold charge
  • Electrical accessories dim at idle: alternator undercharging

2. Visual inspection first

Before any electrical test:

  • Check battery terminals: green/white corrosion indicates sulfation — clean with baking soda solution and wire brush before testing (corrosion increases resistance and mimics battery failure)
  • Check battery case: cracks or bulging indicate internal failure — replace immediately
  • Check alternator drive belt: frayed, cracked, or glazed belt prevents charging regardless of alternator condition
  • Check ground cables: black cables from battery negative to chassis and engine block — loose ground causes widespread electrical symptoms

Read the full file on GitHub · 97 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 10d ago First seen · 97 lines · 47 tokens per session scan A 426823c2b419

Subscribe to this mod's changes

diagnose-battery-charging-problem is a skill published in the GitHub repository jeffreytse/grimoire-core (4 stars, last pushed 22d ago), licensed MIT. It adds 47 tokens to every session and 1,401 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-31.