Editing Direct current (section)

===Automotive===
Most automotive applications use DC. An [[automotive battery]] provides power for engine starting, lighting, the ignition system, the climate controls, and the infotainment system among others.  The [[alternator]] is an AC device which uses a [[rectifier]] to produce DC for battery charging.  Most highway passenger vehicles use nominally  12&nbsp;[[volt|V]] systems.  Many heavy trucks, farm equipment,  or earth moving equipment with [[Diesel engine]]s use 24 volt systems. In some older vehicles, 6&nbsp;V was used, such as in the original [[Volkswagen Beetle|classic Volkswagen Beetle]]. At one point a [[42&nbsp;V electrical system]] was considered for automobiles, but this found little use. To save weight and wire, often the metal frame of the vehicle is connected to one pole of the battery and used as the return conductor in a circuit.  Often the negative pole is the chassis "ground" connection, but positive ground may be used in some wheeled or marine vehicles.
In a [[battery electric vehicle]], there are usually two separate DC systems. The "low voltage" DC system typically operates at 12V, and serves the same purpose as in an internal combustion engine vehicle.<ref>{{Cite journal |last1=Pradhan |first1=S. K. |last2=Chakraborty |first2=B. |date=2022-07-01 |title=Battery management strategies: An essential review for battery state of health monitoring techniques |url=https://www.sciencedirect.com/science/article/pii/S2352152X22004509 |journal=Journal of Energy Storage |volume=51 |pages=104427 |doi=10.1016/j.est.2022.104427 |bibcode=2022JEnSt..5104427P |issn=2352-152X}}</ref> The "high voltage" system operates at 300-400V (depending on the vehicle), and provides the power for the [[traction motor|traction motors]].<ref>{{cite web |last1=Arcus |first1=Christopher |title=Tesla Model 3 & Chevy Bolt Battery Packs Examined |url=https://cleantechnica.com/2018/07/08/tesla-model-3-chevy-bolt-battery-packs-examined/ |website=CleanTechnica |date=8 July 2018 |access-date=6 June 2022}}</ref> Increasing the voltage for the traction motors reduces the current flowing through them, increasing efficiency.