Differences

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--- battery_compatibility:pylontech_phantom [2019-05-17 15:01] – [1. Product & system compatibility] mvader
+++ battery_compatibility:pylontech_phantom [2019-06-21 13:43] – [My system only charges the battery to 52V] iburger
@@ Line 247: / Line 247: @@
 You can confirm if this is affecting your installation be entering the Pylontech Battery menu on your Venus-device, and then the Parameters Menu. This will report the Charge Current Limit (CCL) and Discharge Current Limit (DCL).
+==== My system only charges the battery to 52V ====
+When DVCC is enabled, the battery (via the CAN-bms) is responsible for the charge voltage. The Pylontech battery requests a charge voltage of 53.2V. We have however found that in practice this is too high.
+The Pylontech battery has 15 cells in series, so 53.2V equates to 3.55V per cell. This is very highly charged and makes the system prone to go overvoltage.
+It should also be noted that a LiFePO4 cell stores very little additional energy above 3.45V.
+For this reason we opted to override the BMS and cap the voltage at 52V. This sacrifices almost none of the capacity and greatly improves the stability of the system.
+==== The battery won't charge to 100% ====
+Also see the question above. The state of charge of the battery is estimated based on the overall voltage and on how well balanced the internal cells are. Because we cap the battery voltage at 52V, the state of charge will sometimes rise very slowly once it reaches the mid-90s. This is normal and usually resolves over time.
 ===== 10. Further Information =====