{
  "slug": "diesel-battery-and-charging-system-maintenance",
  "title": "Battery, Charging, and Controls: The Electrical Side of a Diesel PM",
  "description": "Why batteries, charging, and controls get their own section in a PM for diesel trucks and generators, why a standby generator's start circuit matters most, and what the customer's record should show.",
  "track": "maintenance",
  "kind": "article",
  "isRegulatoryAdjacent": false,
  "publishedAt": "2026-10-18",
  "cfr": [],
  "related": [
    "semi-truck-preventive-maintenance-checklist",
    "diesel-generator-maintenance-checklist",
    "generator-load-bank-exercise-record",
    "what-belongs-in-a-pm-report-for-the-customer",
    "record-a-pm-service"
  ],
  "topics": [],
  "nextStep": null,
  "sources": {
    "citations": [],
    "bcpRole": "Blue Collar Parts records the work and sends the report to your customer. It does not perform, certify or approve inspections.",
    "reviewed": "2026-10-18",
    "reviewedEdition": null,
    "reviewedText": "Reviewed 2026-10-18"
  },
  "url": "https://shopbluecollarparts.com/kb/diesel-battery-and-charging-system-maintenance",
  "markdownUrl": "https://shopbluecollarparts.com/kb/diesel-battery-and-charging-system-maintenance.md",
  "body": "**The electrical system decides whether the engine starts, and on a modern diesel it also runs the controls that decide how the engine behaves.** A PM gives batteries, charging, and controls their own section because electrical failures are common, often intermittent, and cheap to catch early compared with the call they cause.\n\nThis page describes the electrical side of a PM at the category level. Test procedures and specifications come from the battery, engine, and controller manufacturers' documentation.\n\n## Batteries and charging\n\nBatteries wear out with age, heat, cold, and how they are used, and the charging system has to keep them ready. Connections corrode and loosen. A PM records the condition of the batteries, their connections, and the charging system so the customer can plan a replacement instead of finding out at a cold start.\n\n## Trucks and tractors\n\nOn a truck, the electrical section of the PM is about one question: will the truck start, and will the charging system keep it running, until the next visit?\n\n## Diesel generators: the start circuit is the job\n\nA standby generator exists to start when the power fails. Its electrical system and controls are what make that happen without anyone present, so generator PM gives them particular weight, and pairs it with an exercise record that shows the unit has actually started and carried load. See [the generator load bank and exercise record](/kb/generator-load-bank-exercise-record).\n\n## What the customer's record should show\n\nThe record should say what was tested, what condition the batteries, connections, and charging system were found in, what was serviced or replaced, and what to plan for. A reading that informed the result belongs with the finding. See [what belongs in a PM report for the customer](/kb/what-belongs-in-a-pm-report-for-the-customer).\n\n## Record it in Blue Collar Parts\n\nThe truck PM form has one **Electrical & Battery** section. The generator form splits it in two: **Battery & Charging System**, where a cranking test reading can go with its item, and **Electrical System & Controls**, which covers the auto-start circuit and the control panel. Findings, readings and notes are entered item by item, and they land in the record your customer receives. See [how to record a PM service](/kb/record-a-pm-service), then [send the record to your customer](/kb/send-a-record-to-your-customer).\n\n---\n\n*Preventive maintenance is not a federal annual inspection and does not establish regulatory compliance. This page describes a system at the category level. Use the equipment manufacturer’s current service documentation for the items to check, procedures, specifications, and service intervals.*",
  "license": "CC BY 4.0",
  "licenseUrl": "https://creativecommons.org/licenses/by/4.0/"
}