Battery isolator
A battery isolator, also known as a split-charge diode, is an electrical device used in multi‑battery electrical systems to permit a single direct current (DC) charging source, such as a vehicle alternator, to supply power to more than one battery while preventing electrical interaction between the batteries. In typical installations, the isolator employs one‑way current control devices (such as diodes or solid‑state switches) so that current from the charging source is directed into each battery circuit without allowing one battery to discharge into another.