philippi Academy

Glossary

By Michael KögelLast reviewed

In short

Terms from vehicle electrical system technology, each defined in one to two sentences and supplemented with practical implications: typical values, units, formulas, and the most common mistake associated with each term. Sorted from A to Z, searchable, with each entry linking to a detailed technical article.

71 terms

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How the Entries Are Structured

Each term begins with a one-to-two-sentence definition—concise enough to be quoted. Below that, you'll find practical implications: typical values, common confusions, and the most frequent mistake made with that term. Where a quantity is meant, the unit is included; where a formula is involved, the formula is provided.

Why a Dedicated Glossary

Vehicle electrical systems are full of terms that are taken for granted in datasheets and used inconsistently in forums. Ampere-hours and watt-hours are confused, depth of discharge and state of charge are equated, potential equalization and ground are lumped together. These ambiguities are not a matter of language—they lead to incorrectly designed systems.

From Term to Depth

Where a term deserves more than just a definition, the entry refers to the specialist article that elaborates on it—and to related terms within the same context. The glossary thus serves as an entry point into the academy, not merely an appendix.

Michael Kögel · Managing Director, philippi elektrische systeme GmbH

Michael Kögel is Managing Director of philippi elektrische systeme GmbH in Remseck am Neckar. Since 1978, the family-owned company has developed and manufactured on-board electrical systems for yachts, motorhomes and special vehicles.

Articles in the philippi Academy are written together with the engineering department and technically reviewed. If a standard or a product specification changes, the article is revised and the review date updated.

Published · Last reviewed

Frequently asked questions. Answered briefly.

How is a glossary entry structured?

Each term begins with a definition in one or two sentences, short enough to be quoted. Below it you will find what it means in practice: typical values, common confusions and the mistake most often made with the term. Where a quantity is meant, the unit is given; where a formula is involved, the formula.

Why is there a dedicated glossary for on-board electrics?

On-board electrics is full of terms that data sheets take for granted and forums use in different ways. Ampere-hours and watt-hours are confused, depth of discharge and state of charge are equated. These inaccuracies lead to incorrectly designed systems. Where a term deserves more than a definition, the entry refers to the relevant Academy article.

Can I compare amp-hours from 12- and 24-volt systems?

No, not directly. An ampere-hour is a quantity of charge, not a quantity of energy: 100 Ah at 24 volts contains twice as much energy as 100 Ah at 12 volts. Only watt-hours are comparable across voltage levels, i.e. ampere-hours times nominal voltage. This also applies when you compare batteries of different voltages using their data sheets.

Glossary

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