Glossary

Charge regulator

What is Charge regulator?

The device that controls the charging process: it sets the charging profile for each battery type, limits current and voltage and switches between the charging phases.

What matters about Charge regulator in practice?

An alternator with an internal regulator only holds a fixed voltage. Only an external multi-stage regulator turns this into a charge with a profile, temperature compensation and a final phase — with lithium it is not optional.

Every regulator kit includes two temperature sensors: one on the battery for voltage compensation, one on the alternator as protection against continuous operation at full output.

Which charging stages does a charge controller manage?

  • Bulk: constant current until the end-of-charge voltage is reached.
  • Absorption: constant voltage while the current drops and the last percent go into the battery.
  • Float: a lowered voltage for lead batteries, with lithium usually switching off instead of holding.

Why must the battery type be set?

Lead-acid, AGM, gel and LiFePO4 need different end-of-charge and float voltages. A wrongly set controller does not fully charge a lead battery or keeps a lithium battery at a high level permanently. The values are in the battery’s data sheet.

Where are charge controllers on board?

In every shore power charger, in solar controllers, in DC-DC chargers and as an external regulator on the alternator. The page charger and inverter gives an overview of chargers and inverters.

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