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--- battery_compatibility:byd_b-box [2022-08-18 09:29] – guystewart
+++ battery_compatibility:byd_b-box [2022-09-01 04:25] (current) – [12. High voltage warning or alarm shown on battery status] guystewart
@@ Line 490: / Line 490: @@
 ===== 12. High voltage warning or alarm shown on battery status =====
-The 'high voltage' warning or alarm is not unusual on new batteries that are not yet balanced. To help the batteries balance quickly, keep the batteries fully charged until the errors go away. In an ESS system, set it to 'keep batteries charged', in an off-grid system the fastest way is to either charge / balance the battery before installation, or to fully charge with a generator if not enough solar is available to keep the batteries fully charged.
+The 'high voltage' warning or alarm is not unusual on new batteries that are not yet balanced. While less common, It can also occur on systems that have been installed and previously working reliably as well.
+It is easiest to confirm this diagnosis in VRM in the Advanced Widget for the Battery Monitor as it logs this data over time.
+{{:battery_compatibility:vrm-enable_maxmin.jpg?600|}}
+It is also possible to see an instantaneous cell max/min on the GX device in the Menu -> BYD Battery -> Details
+In a normal well balanced battery installation, you can see the minimum and maximum cell voltages rising together through most of the charge cycle (within 10%), and power spikes are absorbed by both min and max cells when the battery is full. Once the battery is at 100%, the max cell voltage should fall back closely in line with the minimum cell voltage.
+{{:battery_compatibility:byd-balance_cells.jpg?600|}}
+In an imbalanced battery installation, you can see the minimum cell voltage does not rise as much (if at all), compared to the maximum cell voltage. Once the battery is at 100%, the maximum cell voltage does not fall back closely in line with the minimum cell voltage. Any power spikes are disproportionately affecting the high voltage cells, generating alarms, and putting the system at risk of shutting the battery down.
+{{:battery_compatibility:byd-imbalanced_cells.jpg?600|}}
+To help the batteries balance quickly, keep the batteries fully charged and the system voltage stable until the errors go away. In an ESS system, set it to 'keep batteries charged', in an off-grid system the fastest way is to either charge / balance the battery before installation, or to fully charge with a generator if not enough solar is available to keep the batteries fully charged.
 If you are unable to maintain the target voltage to balance the batteries without the 'high voltage' alarm occurring, you may need to temporarily enable and set the “Limit managed battery charge voltage” setting in the DVCC menu of the GX device. Reduce this voltage as necessary until the alarm stops. After sufficient time to balance the batteries, try increasing this value until it can be disabled again for normal operation.
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 {{:battery_compatibility:byd-highvoltage.jpg?400|}}
+Another method that may also help is limiting the maximum charge current that is provided by the solar chargers. In some cases this can allow a better charge without needing to reduce the overall battery charge voltage as much (or at all), by reducing the high current spikes. Charge current limits can be applied at a system level in DVCC - however they will be much more effective and quicker to react to changing conditions if applied at an individual unit level within the MPPT settings in VictronConnect:
+{{:battery_compatibility:vc_set_max_current.jpg?600|}}
+Start with a severe current limit (i.e 50%) and then see if that resolves the issue (while still making sure the system receives a full charge). If the issue is still not resolved, continue to restrict further.
+Once the alarms stop, then increase Max Charge Current back to the point where the issue reappears, and then reduce it again by 10%. Note this may also be seasonally affected (if solar window is limited with the changing sun angle).
+All of these values can be monitored, and the settings adjustments can be performed remotely with an internet connected system via VRM and VictronConnect Remote.
-If it is not possible to raise the voltage over time, and eventually disable this manual override:
+If it is not possible to raise the voltage or current limits over time, and eventually disable the manual overrides without the alarms reoccurring;
-: If you have 2 or more batteries in your system, you can try shutting down the system once it is as close to fully charged as possible, and then physically connecting the batteries in smaller groups (or even individually) so that balancing can occur on each individual battery without it being masked by the others connected in parallel. It may help you to see the indicator lights on the battery (if available on that model) to find which battery might be out of balance with the others.
+: If you have 2 or more batteries in your system, you can try shutting down the system once it is as close to fully charged as possible, and then physically connecting the batteries in smaller groups (or even individually) so that balancing can occur on each individual battery without it being masked by the others connected in parallel. It may help you to see the indicator lights on the battery (if available on that model) to find which battery might be out of balance with the others. You can also monitor this in VRM and the GX device using the min/max cell voltage reporting.
-: Contact your dealer for further assistance (they can provide additional software to see individual cell level data), or assist with other potential solutions.
+: Contact your BYD dealer for further assistance (they can provide additional software to see even more detailed individual cell level data), or assist with other potential solutions.
 ===== 13. Further Information =====