How to setup the AutoLevel bypass configuration on the WatchMon
Process to enable the CMU CellMon modules to adopt the AutoLevel extra bypass configuration to improve the management beyond top level balancing.
PLEASE NOTE: AutoLevel extra bypass is NOT suited to LiFePO4 battery chemistry as the Voltage Curve is too flat for this to be effective.
WARNING: Leaving on long term may cause overheating that will shorten the life of the cell monitor. To be used short term where top balancing is not possible.
Step 1 - Navigate to the Hardware menu.
Step 2 - Navigate to the CellMon tab.
Step 3 - Put in Edit mode to make changes, only available when in Technician mode.
Step 4 - Select the Extra Bypass mode in the drop down field
There are 3 options:
- None - disable any additional adjustment.
- Idle Shunt - triggers bypass on any high cell voltage to match low when Shunt Idle state.
- Same Cell Volt - trigger bypass on any high cell voltage to match low.
- Auto Level - trigger bypass on any high cell voltage to match when the criteria allows this process to run.
Step 5 - Navigate to the Extra Bypass configuration via more
Step 6 - Adjust field values
Step 7 - when done press OK to save
Step 8 - press Save on form
To store the values into system and return to read only mode.
Step 9 - Monitor supervisor, when activated shows a balance status icon
Different gap cell volt: 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 that are 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: Duration that the bypass will be run if triggered (seconds)
Cell volt stable time Interval: Duration that the cell monitoring voltages need to not vary, typically 120 seconds. This prevents the 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.
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 this is typical 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 style of balancing where voltage is 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 being used constantly as continuous use will reduce the life of the cell monitor
All targets need to be met, hence if one is outside the requirements this then disables the process until all are 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.
The SoC% need to be met even for a system without a shunt. Hence set the SoC% actual value to that about your threshold set.