Alternators are used in modern automobiles to charge the battery and to power the electrical system when its engine is running. All cars with an internal combustion engine except for some hybrids have an alternator. When an engine is running, the alternator charges the battery and supplies additional electric power for the vehicle electrical systems. An alternator is bolted to the engine and is driven by a serpentine belt/drive belt.
Maxpeedignrods alternators have several advantages that are lighter, cheaper, more rugged, and can provide useful charge at idle speed.