ONYX BMS App (What It Shows and How to Use It)

This page is part of the ONYX Battery Guide

ONYX 72V 45Ah BMS App

This post explains how ONYX BMS apps function across 72V and 80V 45Ah batteries and 41Ah systems. It covers app compatibility, connection behavior, voltage interpretation, and the differences between read-only and configurable BMS platforms. It also explains what the app can and cannot show, and how to correctly use BMS data for real-world diagnostics.

BMS apps report battery data, but they do not represent full real-world behavior. Accurate diagnostics require combining BMS data with observed riding performance, especially under load.

The ONYX 72V 45Ah BMS app provides direct visibility into battery state without requiring external tools or manual measurement. It works whether the battery is installed in the bike or removed, giving consistent access to voltage, cell data, and temperature.

This app is designed for the ONYX 72V 45Ah battery and reflects its voltage range, thermal limits, and balancing behavior.

Compared to earlier ONYX battery systems, this version removes unnecessary controls. There is no option to disable charge or discharge ports. This is intentional, as the system uses a QS8 anti-spark connector on the discharge side, improving safety and simplifying operation.

The same BMS app is also used on the ONYX 80V 45Ah battery.

There is no difference in app functionality, layout, or behavior. The only difference is the operating voltage range of the battery.

All readings, including total voltage, cell data, temperature, and delta, behave the same way but scale to the higher voltage system.

BMS App Compatibility

ONYX uses different BMS apps depending on the battery type.

BMS Apps by Battery Model

BMS App iPhone & Android

Downloads

• Super Power BMS (iOS / Android)
• Overkill Solar BMS (iOS / Android)
• Xiaoxiang BMS (iOS)
• ANT BMS (iOS / Android APK via community folder)

Charge and Discharge Port Behavior

• QS8 batteries (ONYX 72V 45Ah and ONYX 80V 45Ah)

  • no need to disable discharge
  • no option to disable charge or discharge in the app
  • fully passive, plug-and-play operation
  • QS8 anti-spark connector prevents arcing

• SB50 batteries (ONYX 41Ah and similar systems)

  • discharge must be disabled in the BMS app before connecting
  • prevents connector arcing and damage
  • charge/discharge control is user-accessible

41Ah Battery Note

• no physical power switch
• discharge control handled through BMS app
• avoid modifying advanced settings

Incorrect configuration can cause:

• early cutoff
• incorrect state-of-charge reporting
• false imbalance readings
• unsafe operation

System Overview

Voltage Scaling Behavior (72V vs 80V)

Both 72V and 80V systems use the same underlying cell structure:

• 20 series cell groups (20s)
• identical per-cell voltage limits
• identical balancing behavior

The only difference is total pack voltage.

Implications:

• all diagnostics logic remains the same
• cell-level interpretation does not change
• only total voltage ranges differ

Misapplying 72V expectations to an 80V battery will lead to incorrect conclusions.

Behavior Overview

The app is structured into multiple pages, each exposing a different level of battery detail.

• Page 1 → connection / overview
• Page 2 → main dashboard (voltage, temperature, status)
• Page 3 → per-cell data and voltage delta

Core metrics update in real time when connected.

Configuration Access Differences

• 45Ah (Super Power BMS) → read-only monitoring
• 41Ah (Xiaoxiang / Overkill) → configurable settings
• ANT-based systems → fully configurable

Implication:

• 45Ah diagnostics rely purely on observed data
• 41Ah diagnostics may involve correcting configuration
• incorrect settings can create false diagnostic symptoms

Control Limitations (Super Power BMS)

The Super Power BMS app used on ONYX 72V 45Ah and 80V 45Ah batteries does not provide:

• charge port disable
• discharge port disable
• user-accessible protection settings

This is intentional.

The system is designed as:

• read-only monitoring
• fixed protection behavior
• hardware-based safety (QS8 anti-spark)

Setup / Connection

• power on the battery
• open the BMS app
• connect via Bluetooth
• wait for data to populate
• navigate between pages

Connection behavior is consistent whether the battery is mounted or removed.

Connection Issues

• app does not find battery
• connection drops immediately
• app connects but shows no data

Common causes:

• battery not powered on
• Bluetooth permissions disabled
• wrong app for battery type
• multiple BMS apps conflicting
• device compatibility limitations

Additional notes:

• some apps rely on Bluetooth Low Energy (BLE), which behaves differently across devices
• Android devices may have inconsistent BLE scanning behavior depending on version and manufacturer
• some users rely on specific APK versions for ANT or legacy app compatibility
• location permissions may be required for Bluetooth scanning on Android
• iOS behavior is generally more consistent across supported apps
• only one BMS app should be open at a time when connecting

Technical Fundamentals

The BMS monitors grouped lithium-ion cells and reports both pack-level and cell-level data.

• total voltage reflects overall state of charge
• temperature sensors monitor internal conditions
• cell balancing equalizes voltage across groups
• protection systems prevent unsafe operation

All values are reported in real time when connected.

Important:

• data is sampled and reported, not a perfect real-time physical representation
• rapid high-current events may not be fully reflected in app readings

Full Configuration Tables

Total Voltage

The main screen shows total battery voltage.

72V System

80V System

Important:

• always interpret voltage based on battery type
• applying 72V voltage expectations to an 80V battery will produce incorrect diagnostics

SOH

SOH (State of Health) reflects remaining usable capacity over time.

Cell Temp

Cell temperature is shown on the main screen.

Note:

• internal sensors do not always capture the hottest cell group
• temperature readings should be treated as representative, not absolute

Voltage Difference

Cell voltage delta is shown on the cells page.

Important:

• check delta at full charge and after riding
• evaluate alongside performance behavior
• low delta does not guarantee good performance
• high delta combined with cutoff indicates imbalance

Common BMS Misinterpretations

• full voltage does not mean full capacity
• low delta does not mean a healthy battery under load
• normal temperature does not mean safe operation at high current
• stable readings at rest do not reflect behavior under throttle

These are the most common sources of incorrect diagnosis.

Limitations of the BMS App

The app does not show:

• internal resistance
• true capacity under load
• real-time cell collapse under high current
• mechanical faults (loose balance leads, solder issues)

Important:

• a battery can appear normal in the app and still fail under load
• the app cannot detect all failure modes

Using This Data for Diagnostics

The BMS app provides the raw data needed to evaluate battery condition.

Live vs At-Rest Data

• at rest → shows balance and static condition
• under load → reveals weak groups and sag behavior

Best practice:

• check voltage and delta at full charge
• observe behavior during riding
• compare post-ride readings

When Not to Trust the App Alone

• battery cuts out under load but looks normal
• voltage rebounds immediately after cutoff
• performance is weak despite good readings

In these cases, real-world behavior overrides app data.

For interpreting voltage behavior, cell imbalance, temperature trends, and real-world performance:

• Read: ONYX Battery Diagnostics

Hardware / Cooling

• internal sensors track temperature across the pack
• QS8 connector reduces arcing during connection
• no user-controlled switching reduces failure points

Thermal behavior depends on:

• load
• ambient temperature
• airflow

Sensor readings represent internal averages, not exact hotspot temperatures.

Final Advice

• use voltage as your primary state-of-charge reference
• always match voltage expectations to battery type (72V vs 80V)
• monitor cell voltage delta periodically
• confirm behavior under load, not just at rest
• do not rely on app data alone for diagnostics
• avoid charging at elevated temperatures
• use the app regularly to understand long-term behavior trends

The BMS app is a monitoring tool. Correct interpretation requires combining app data with real-world performance.