¶ How to Set Up The AutoLevel Bypass Configuration On The WatchMon
This describes the process to enable the CMU CellMon modules to adopt the AutoLevel extra bypass configuration to improve the management beyond top-level balancing.
AutoLevel is NOT suited to LiFePO4 battery chemistry as the Voltage Curve is too flat for this to be effective. Use "R4 Timed Latch" instead
Leaving cells permanently balancing all the time will damage the cell monitor. This should only be used when cells are significantly out of balance. Cell monitors are not designed to run continuously indefinitely — this will shorten their life.
When wanting to use it for short term (running for a few days) such as when first commissioning a pack is fine; however, running 24/7 for weeks is not ideal and not their intended use. If this is required or configured to have this outcome, it's best to revisit the battery pack, check what might be wrong and take action (cell replacement, etc). The cell monitors are designed to handle up to 6Ah/day with a typical system only needing 0.15Ah/day close to its end of life.
¶ 1. Navigate to the Hardware menu.
¶ 2. Navigate to the CellMon tab.
¶ 3. Put in Edit mode to make changes.
Only available when in Technician mode.
¶ 4. Select the Extra Bypass mode in the drop-down field.
The following options are available:
| Mode | Description |
|---|---|
| None | Disable any additional adjustment. |
| Reserve 1 (Idle Shunt ) | Triggers bypass any high cell voltage to match low only when Shunt Idle state. Recommend to adopt Auto Level if wanting to use Reserve 1 and 2. |
| Reserve 2 (Same Cell Volt) | Trigger bypass on any high cell voltage to match low. Recommend to adopt Auto Level if wanting to use Reserve 1 and 2. |
| Auto Level Optimized for LMC chemistry |
Trigger bypass on any high cell voltage to match when the criteria allow this process to run. |
| Reserve 4 (Latched Bypass) Optimized for LifePO4 chemistry |
A latched approach is used to utilise the charging better and continue even when the charging is paused to ensure that the cells continue to balance. Holds the balancing when the cell reaches the target voltage even after charging has been paused and the voltage drops so that the cell continues to discharge to allow the remaining cells in the pack to catch up. |
¶ 5. Navigate to the Extra Bypass configuration via More.
¶ 6. Adjust field values.
¶ 7. When done press OK to save.
¶ 8. Save on form.
To store the values in the system and return to read-only mode.
¶ 9. Monitor supervisor, when activated shows a balance status icon
¶ Field Definitions
| Different Gap Cell Volt | The threshold that the cell voltage is greater to start adjusting to bring to the limits. Typically 0.01V |
| Bypass Banding Cell Volt | Limit the cell monitors within the range. Hence only process the highest values rather than all at once. Typically 0.05V |
| Cell Volt Low Cutout Limit | Ensure that if the lowest cell voltage goes below this threshold the process will not run. |
| SoC% Low Cutout Limit | Ensure that if the SoC% goes below this threshold the process will not run. |
| Shunt Charge Current Limit | Maximum shunt current that the bypass process will run when the batteries are charging. |
| Shunt Discharge Current Limit | Maximum shunt current that the bypass process will run when the batteries are discharging. |
| Bypass Extra Time Interval | The duration that the bypass will be run if triggered (seconds) |
| Cell Volt Stable Time Interval | The duration that the cell monitoring voltages need to not vary, typically 120 seconds. This prevents the process from running when the battery has a transient. |
| Bypass Thermal Relief | This is an indicator only. Thermal relief occurs when bypassing overheats the circuit board, It will stop till it cools down below the maximum temperature. How long this takes isn't fixed as using a fan or having good air flow will reduce the time to cool down. |
¶ Targets
| Shunt Charge Current Limit | Enough to allow balancing whilst in bulk charging mode. Hence if a solar charger has 5kW output for a 48V nominal system. Example: 85.0A = 5000 Watts / (4.10v x 14) |
| Shunt Discharge Current Limit | Enough to allow balancing is typical of the base load of the system that varies for every project. Example: 3.0A = 150 Watts / (50V) |
| Cell Volt Low Cutout Limit | This is dependent on the cell chemistry. Typically for LMC, this is 3.85v or higher is a good starting place. Take care with using this function for LiFePO4 as this chemistry is not suited to this balancing style where voltage does not indicate SoC%. If you do adopt for LiFePO4 a target greater than 3.45V is a starting point. |
| Target Bypass Extra | Limits the maximum use per day of Bypass Extra. This is to prevent this from being used constantly as continuous use will reduce the life of the cell monitor. |
¶ Troubleshooting
Remember: Text will appear in yellow when exceeded the targets or when not being met.
- If the cell voltage changes by more than 0.01V on the min or max reading then the system will restart the interval timer to wait for the stable time interval.
Sample: Anything below the value of 3.4V is below the threshold hence why it is not balancing.
- The SoC% need to be met even for a system without a shunt. Hence set the SoC% actual value to that of your threshold set.
Sample: Anything below the value of 85% is below the threshold hence why it is not balancing.
- The default values of the Shunt Charge/Discharge Current Limit are close to zero (0) to ensure balancing only occurs when idle. However, you can increase this number if you want it to have this balancing when charging or discharging.
Balancing will only start when it's allowed to balance and within the threshold of the following:
