Micha Solar MSRx Charge Controller User Operation Manual
Page 4 of 46 Document: 802440-30.doc Date: December 2020 www.micha.co.uk
3.4. Battery Voltage Regulation Algorithm
In Software 801313 Version 5.0 and above the following Battery Voltage Regulation Algorithm is used:
The Battery Voltage is read every 0.1 seconds (the instant value). If the Compensated Instant Battery
Voltage is greater than or equal to the Battery Regulation Voltage, then all the Array Relays will be
disconnected and charging will stop immediately.
The Battery Voltage last 8 values are averaged, which is used for the Battery Voltage display. If the
Compensated Average Battery Voltage is less than the Battery Regulation Voltage minus the Regulation
Hysteresis Voltage (0.3V) then an Array Relay will be requested to be connected.
An Array Relay may only be connected if the open-circuit voltage of the PV Array is more than 2V above
the Battery Voltage.
The Array Connection Delay is 60 seconds.
After power up, there will be a delay of 60 seconds before the first Array is connected.
After any Array disconnection, there will be a delay of 60 seconds before any Array is connected.
After one Array is connected, there will be a delay of 60 seconds before the next Array is connected.
The Arrays will be used in such a way to distribute the operation among the Array Relays:
MSRx2 (2-stage Controller) => Array Relays are used in rotation: 1, 2
MSRx4 (4-stage Controller) => Array Relays are used in rotation: 1, 3, 2, 4
MSRx6 (6-stage Controller) => Array Relays are used in rotation: 1, 5, 3, 2, 6, 4
MSRx8 (8-stage Controller) => Array Relays are used in rotation: 1, 5, 3, 7, 2, 6, 4, 8
3.5. Array Voltage Measurement
The open-circuit Array Voltage is measured by disconnecting the Array from the Battery. If an Array
Input is connected to the Battery then the Array Relay is opened after a time interval to measure the
voltage.
3.6. System Normal / Common Alarm
System Normal is active if no Alarms are active.
Common Alarm is active if any Alarm is active.
3.7. High Voltage 1 & 2 Alarms
If the Compensated Battery Voltage is greater than or equal to the High Volts Set Voltage for the High
Volts Alarm Delay time, then the High Volts Alarm will be activated. If the Compensated Battery Voltage
is less than or equal to the High Volts Reset Voltage then the High Volts Alarm will be de-activated.
2 x High Volts Alarm functions are provided: HV1 and HV2 (HV2 is disabled by default).
When High Volts 1 Alarm is active, all the Array Relays will be disconnected.
3.8. Low Voltage 1 & 2 Alarms
If the Battery Voltage is less than or equal to the Low Volts Set Voltage for the Low Volts Alarm Delay
time, then the Low Volts Alarm will be activated. If the Battery Voltage is greater than or equal to the
Low Volts Reset Voltage then the Low Volts Alarm will be de-activated.
2 x Low Volts Alarm functions are provided: LV1 and LV2 (LV2 is disabled by default).
