Bypass Extra Mode

Bypass Extra Mode allows bypassing to balance batteries whilst not full.  It is not recommended for LiFePO4

Do not leave on permanently.  

This is usually a short term fix where your batteries are seriously unbalanced and top balancing is not possible.

The standard bypass is a function controlled by the cell monitors where as they reach the Bypass limit they release energy via heat allowing the other batteries to catch up.  This continues to operate whether or not a WatchMon is connected.

Extra Bypass Mode There are 3 options and they follow our development with each extra option getting better than the last,  Bypass Extra Mode is not recommended on LiFePO4 due to the nature of it's voltage curve and EV due to fact it cycles empty to full already frequently and hence is unnecessary.

This mode is most important where the full and empty state are rarely achieved and hence the need to find another balancing option is vital.  If the system is rebooted this is automatically changed to off as it is important that it is consciously chosen and set to suit your system rather than just left on permanently,

Evolution

Our first try was - Idle Shunt -  This triggers bypass on any high cell voltage to match low but only occurs when no other charging occurs i.e. when Shunt Idle state.

Next we tried - Same Cell Volt - This can occur without a shunt being present and triggers bypass on any high cell voltage to match low.

Our latest option is - Auto Level - Here we have a more complex algorithm for using bypass to balance the batteries when not full.  You can set limits on how many will bypass at once, how much higher a battery needs to be and in what other circumstances.  You can set limits to not bypass below a particular SOC% and it will not bypass if any of the set rules will be broken.  When you select the More option next to Bypass Extra Mode any rules that are currently broken preventing auto-level are highlighted in yellow giving you the option to go in an decide if that rule is one you want to keep or not,

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 - press Save on form 

To store the values into system and return to read only mode.  

Step 6 - Monitor supervisor, when activated shows a balance status icon

AutoLevel Bypass settings are accessed via the More 

By clicking on More

Any fields highlighted in yellow will prevent Bypass Auto Mode from activating.

Cell Volt Comparison;  - This is the difference necessary before balancing will occur.

Cutout Limit:  These are the criteria that causes existing bypassing to stop.  An individual cell measurement below the Cell Volt Low Cutout, An overall SOC% too low and for bypass relief to allow the cell monitor to cool.

Time Interval:  The first field specifies maximum time bypass occurs for if it doesn't cutout for thermal relief and the second is the time from bypass ceasing till the next measurement is taken.  Temperature does effect the calibration of the cell monitors

Current Threshold:  These are the limits for the amount of current for bypass.

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