Glossary

Load shedding

Also Battery protect, Low Voltage Disconnect

What is Load shedding?

Automatic disconnection of loads when the state of charge or the voltage falls below a set threshold. It protects the battery bank against deep discharge.

What matters about Load shedding in practice?

The threshold is chosen according to the battery type and should not be set too tight — under load the voltage sags without the battery bank being empty. Load shedding that responds to the measured state of charge rather than the voltage works much more reliably.

Safety-relevant loads — bilge pump, navigation lights, alarm — do not belong on the shed circuit. Digital switching modules often offer battery protection per output, which makes this separation easier.

When should load shedding switch?

For lead batteries typically before the permitted depth of discharge is exceeded, for lithium batteries well before the BMS disconnects. The BMS is the battery’s last line of protection; load shedding should act earlier and switch the supply off in an orderly way.

Voltage or state of charge as the threshold?

The voltage drops under load and recovers afterwards. Load shedding by voltage therefore needs a delay, otherwise it switches off when a large load starts. Load shedding by state of charge, supplied by a battery monitor with a shunt, works more precisely.

Which loads belong on load shedding?

  • Comfort loads such as cool box, inverter, lighting and entertainment.
  • Not bilge pump, navigation lights, gas detector and alarm system.

The term deep discharge explains what happens when a battery is discharged too far.

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