BMS Protection Measures

Created by Scott Chen, Modified on Mon, 2 Feb at 12:40 AM by Scott Chen

Protection measures are the automatic safety actions performed by the Battery Management System (BMS) to protect the battery, connected equipment, and user when abnormal conditions occur.

In simple terms:

 They are the built-in “self-defense mechanisms” of the battery.

 Typical Protection Measures in LFP Batteries

Protection Measure

What It Protects Against

What the BMS Does

Over-charge protection

Voltage too high

Stops charging

Over-discharge protection

Voltage too low

Cuts off output

Over-current protection

Excessive current

Disconnects load

Short-circuit protection

Direct short

Instantly disconnects

High-temperature protection

Battery too hot

Stops charge/discharge

Low-temperature charge protection

Charging below 0°C

Blocks charging

Cell imbalance protection

Cells drifting apart

Activates balancing

Communication fault protection

Data loss/errors

Enters safe mode

What “Protection Measures Triggered” Means

When an app or log says:

Protection measures triggered

It means:

The BMS detected an unsafe condition
It temporarily disconnected charging or discharging
The battery is preventing damage

It does NOT automatically mean the battery is defective.

? Common Real-World Causes

  • Load draws more current than battery rating
  • Charger voltage too high
  • Battery discharged too deeply
  • Charging attempted below freezing
  • Loose or undersized cables
  • Corroded terminals
  • Short circuit or wiring fault

 Why Repeated Triggers Matter

Occasional trigger = normal protection
 Frequent triggers = system problem

Repeated protection events usually indicate:

  • Undersized wiring
  • Incorrect charger settings
  • Load exceeding battery capability
  • Installation issues

 These should be corrected.

 

Bottom Line

Protection measures are a feature, not a failure.

They mean the battery is:

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