When diagnosing a Pylontech battery module, it’s helpful to understand the key voltage, current, and temperature thresholds programmed into the BMS. The following table summarises thefactory-level thresholdsfor a US2000B(Plus) with firmware V2.4.
🔋Module Voltage Settings
Parameter
Value (V)
Description
Module Over-Voltage Threshold
54.0
Maximum pack voltage before charge cut-off
Module Over-Voltage Release
52.0
Voltage where charge resumes
Module High-Voltage Threshold
53.7
Warning level before over-voltage protection
Module High-Voltage Release
52.5
Recovery point after HV alarm
Module Low-Voltage Threshold
46.0
Low pack voltage protection point
Module Low-Voltage Release
47.0
Voltage where discharge resumes
Module Under-Voltage Threshold
44.5
Critical pack undervoltage limit
Module Under-Voltage Release
49.0
Recovery voltage after UV protection
Module Sleep Voltage
38.0
BMS low-power sleep threshold
🔋Cell Voltage Settings
Parameter
Value (V)
Description
Cell Over-Voltage Threshold
3.65
Maximum cell voltage during charge
Cell Over-Voltage Release
3.50
Charge resumes once below this
Cell High-Voltage Threshold
3.60
Warning prior to full over-voltage
Cell High-Voltage Release
3.50
HV recovery point
Cell Low-Voltage Threshold
3.05
Minimum safe discharge voltage
Cell Low-Voltage Release
3.10
Resume discharge after recovery
Cell Under-Voltage Threshold
2.90
Deep undervoltage protection
Cell Under-Voltage Release
3.25
Resume normal operation
Cell Shutdown Voltage
2.50
Hard cutoff to protect the cell
🌡️Temperature Protection (Charge)
Parameter
Value (°C)
Description
Charge Over-Temp Threshold
61
Charge cut-off to prevent overheating
Charge Over-Temp Release
55
Temperature where charging resumes
Charge High-Temp Threshold
59
High-temp warning limit
Charge High-Temp Release
55
Recovery temperature
Charge Low-Temp Threshold
−9
Charging disabled below this point
Charge Low-Temp Release
−5
Resume charging when warmed up
Charge Ultra-Low Temp Threshold
−11
Safety limit for extreme cold
Charge Ultra-Low Temp Release
−5
Resume after warming
🌡️Temperature Protection (Discharge)
Parameter
Value (°C)
Description
Discharge Over-Temp Threshold
61
Cut-off to prevent cell overheating
Discharge Over-Temp Release
55
Resume discharging
Discharge High-Temp Threshold
59
Warning level before OT protection
Discharge High-Temp Release
55
Recovery temperature
Discharge Low-Temp Threshold
−9
Discharge limit in cold conditions
Discharge Low-Temp Release
−5
Resume once warmed
Discharge Ultra-Low Temp Threshold
−11
Absolute minimum operating temp
Discharge Ultra-Low Temp Release
−5
Recovery temperature
⚡Current & Protection Delays
Parameter
Value
Description
Charge Over-Current Trip
102 A
Charge current cut-off
Charge Over-Current Alarm
50 A
Early warning threshold
Charge Over-Current Release
40 A
Recovery point
Discharge Over-Current Trip
−100 A
Discharge current cut-off
Discharge Over-Current Alarm
−50 A
Warning level
Discharge Over-Current Release
−45 A
Recovery point
Over-Current Delay
15 000 ms
Time before protection triggers
Over-Current Release Delay
60 000 ms
Reset delay after protection
🔁Secondary & Short-Circuit Protection
Parameter
Value
Description
Secondary Charge Over-Current Trip
200 A
Secondary protection threshold
Secondary Discharge Over-Current Trip
−200 A
Secondary protection threshold
Secondary Protection Delay
100 ms
Trigger delay
Secondary Release Delay
60 000 ms
Recovery delay
Short-Circuit Trip
−400 A
Instant cut-off
Short-Circuit Delay
0 ms
Immediate trigger
Short-Circuit Release
60 000 ms
Reset delay
Idle Shutdown
72 h
Automatic sleep timer
Under-Voltage Shutdown
2 400 s
Deep-discharge timer
🧭 Summary
These parameters define how theBattery Management System (BMS)protects each cell and the overall module from over-voltage, over-current, temperature extremes, and prolonged under voltage.
They are designed to be conservative by design—ensuringcell longevity,thermal safety, andconsistent balancingacross the pack, but these could be lowered further to help protect cells from swelling.
