Beta N
Beta N
Beta N

Off Grid PCU

Beta N

This product is specially for Nepal...
PCU is a Solar Power Conditioning Unit (PCU) which uses Solar energy (primary) and also the power from grid (secondary), to charge the batteries. Since usage of power from grid is secondary, grid power is only used when solar energy is not present and battery voltage level reduces to a certain level. Grid power is also needed when solar power is reduced to a certain level and battery voltage is reduced to a certain level.
Beta PCU has the following features:
1. DSP base design built in MPPT solar charge controller.
2. Most advanced LCD features with AC & DC energy meters.(optional)
3. USB/Ethernet based monitoring with 30 days data storage. (optional)
4. Maximum preference to solar. Smart PCU.
5. No load shut down.(optional) By default factory setting-Disable
6. Capability of 100% panel rating.
7. Unity power factor on requirement.
8. Compatible with all PV arrays having different no. of cells.(36 cell/60 cell/72 cell)
9. Tested as per IEC/MNRE parameters. 1-5 KVA MNRE Approved.
10. Single card design more reliable as less wiring is done and has less weight.
11. Lightening protection.
12. All fault display on front panel.
13. High efficiency MPPT and Inverter.
14.1-5 KVA MNRE Approved.
15. No Load Shutdown – Enable / Disable
16. Grid Charger – Enable / Disable 




Possible Cause & Their Solution


System Not ON.

No Indication,

No display light glow.

1. Check battery terminals & wire also check DC bus at terminal block, it should be around 48V.

2. Check the DC Fuse.

3. Check SMPS is working or not (if working then green LED will glow on main card),

4. 10 pin FRC display connector may be loose.

5. System On/Off Switch (microswitch) may be faulty.


When Press switch and INV not on

No INV ON indication, no buzzer, no output

1. Check FRC cable connection, it may be loose.

2. DSP card may be faulty.

3. MOSFETS may be faulty. If MOSFETs are faulty, change MOSFETs.


Inverter output voltage very high and not controlled by varying

the OPV voltage pot.

SYS ON high

,INV ON high


1. O/P FB pot. may be fault

2. Neutral Wire on CN5 CNG connector could be loose.

3. Check DC FUSE.


No output

on inverter mode

Sensing low battery

Bat. Low indication blinking


1. Battery connection at battery terminals are not proper, they should be tight. Check if there is Carbon/ sulphation. On batt. Terminal.


Overload without any load

Overload indication high

1. C.T. Wire/ SHUNT wire is not connected or open

2. CNG Connector CN5 may be loose.


No buzzer in

Battery low, overload & mains fail condition

Bat. On & bat. Low In mode/ UPS mode.

1. Transistor Q19 or buzzer may faulty.

2. Buzzer may be faulty


System not Sensing Main


1. Check AC fuse/ MCB. It may be blown off or it is not properly tight in the fuse holders before this it should be checked that mains voltage is present at Input Mains lead.

2. Trigger TFR TX1 (0-10v/0-220) may be faulty or dry soldered.

3. Input wire connected to relay (RED) could be loose.

4. Mains in PCU mode could be lower than 175V AC or higher than 270V AC.


System not Charging battery


Mains on

Inv. Mode.

1. Charging Pot may be faulty.

2. Check the external wire connection from shunt.

3. IC OP07 (U13) may be faulty.

4. Battery may be faulty.


Battery Charging




1. Charging Pot may be faulty.

2. Capacitor C4 (104pf) may be faulty.

3. R120 may be faulty.

4. +3.3V, check the OP07 Pin No-7.

5. 5819 diode D42 may be short.

6. Check the external wire connection from shunt.

7. IC OP07 (U13) may be faulty.

8. Battery may be faulty.


AC I/P fuse

Blowing repeatedly


Mains on

Inv. Mode

1. Inv. may have excessive load on it. Remove the extra load. Because in mains time, current passes through this fuse.

2. Charging current Uncontrolled.

3. Bypass switch may be short.


Humming Noise in Charging

Inv. On & Grid charging On

1. Charging current uncontrolled.

2. IR2110 ICs may be faulty.

3. MOSFETs may be loose.


Very Low back

Up time.


1. Duration of Mains supply may not be enough to recharge the Battery / Batteries.

2. Battery terminals may have corrosion on them. Clean with hot water. Shred the end of the wire connected battery, strip it and re-connect it to the battery terminals.(If there is corrosion on the wires). After re-connecting apply Vaseline or white Petroleum jelly on the terminals. Also check battery water level.

3. BV preset may be faulty and not proper setting.

4. One or more cells of the battery could be defective.


DC fuse blowing

Continuously on

Inverter mode.


No Indication

1. MOSFETs may be short.

2. Main transformer may be short.

3. DC fuse are of lower rating.


No output on

Mains mode .


Mains ON

Inv mode

1. Relay may be faulty.

2. Check the relay coil & 12V.

3. Check the transistor Q20 which is driving the Relay.


Sensing Mains without Mains


Mains ON/INV ON Blinking. Inv mode/ UPS Mode,

1. Mains low cut preset could be open.

2. Out capacitor dry or defective connected at O/P socket.

3. Relays could be stuck.

4. Reverse phase may be in O/P.


System is working on Mains/Battery


No Indication.

1. 10-Pin FRC connector may be loose.

2. LED may be faulty.

3. LCD Card Microcontroller pins are faulty.

4. UART PINs 33&34 may be faulty.


Over heat led is coming

Over heat

1. Check the NTC connected with MOSFET heat sink and PCB.

2. Check the fan connection.


Solar charger not ON


No Indication

1. Check open circuit voltage at CNG connector CON3. It should be in range between 60V to 180V.

2. R133 may be open.


Solar charger ON/ but not charging battery


1. Check status screen on LCD in which condition SPV charger off.

2. Check gate drive connector properly connect with IGBT module.


LCD card not display any data/No indication on

No indication

1. Check 10 Pin FRC connector, it may be loose.

2. LCD card controller may be faulty.

Connect Batteries:
    1. Check the polarity of batteries.
    2. Connect the red wire to the positive terminal and the black wire with the negative terminal of the battery.
    3. Depending on the system voltage we may need to connect the batteries in series.
    4. To connect batteries in series, connect negative terminal of one battery with the positive terminal of the adjacent battery. Continue this until you obtain the desired system voltage.
Connect Solar Panel(s):
    1. While connecting solar panel to the system, total solar array voltage must be less than maximum solar panel open circuit voltage of the system.
    2. Positive terminal (+ve) of solar array must be connected to the positive terminal (+ve) of the SPV terminal block and negative terminal (-ve) of solar array must be connected to the negative terminal (-ve) of SPV terminal block.
Connect Grid:
    1. Connect the phase of grid with phase terminal of the Mains terminal block marked as `P`.
    2. Connect the neutral of grid with neutral terminal of the Mains terminal block marked as `N`.
    3. Then switch ON the Mains MCB.
Connect Load:
    1. Connect the input plug of the load into the output socket of the system.