Alfa+ PCU
Alfa+ PCU
Alfa+ PCU

Off Grid PCU

Alfa+ PCU

PCU (Power Conditioning Unit) is an integrated unit consists of grid charger, inverter, MPPT Solar Charger. It continuously monitors Battery and Solar voltage as well as Grid and Output voltage with their currents.
MPPT based solar charger extracts the maximum power from the solar panels whereby it increases the efficiency of the system. MPPT charger has multistage charging which maintains the battery charging voltage such that it increases the lifespan of battery.
ALFA PCU is a Model of Power Conditioning Unit (PCU) which uses Solar  (primary) and  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 11.5V/Battery (Default 11.5V, Configurable).  

Grid power is also needed when solar power generation is less and battery voltage is reduced to 11.5V/Battery (Default 11.5V, Configurable).

Sr. No.



Possible Cause & Their Solution


System Not ON

No Indication,

no display light glow

  1. Check Battery Terminals & Wire also check dc bus at HT, it should be around 48v.

  2. Check the DC Fuse.

  3. 10 pin FRC Display Conn. May Be Loose.

  4. System On/Off switch (Micro Switch) may be faulty.


When Press switch and INV not ON

No INV ON indication, no buzzer, no output

  1. Check FRC cable connection may be loose.

  2. DSP card may be faulty.

  3. Check battery voltage reference at pin 12, it should be 1.65 volt for 48 volt system.


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.


Very low output voltage or fluctuation in inverter mode.

Inv mode/ups indication high

  1. One channels of mosfet’s may not be working then        

  2. Check the Drives of all channels also check the ICs, IR2110.

  3. O/P voltage preset may be faulty.

  4. o/p voltage step down TFR TX2 may be faulty


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. 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. 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.


Very Low back

Up time.

No Indication

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


DC fuse blowing

Continuously on

Inverter mode.

No Indication

  1. OPV more than 220V AC.

  2. DC fuse low rating.


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.


Over heat led is glowing

Over heat

  1. 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.


LCD card not displaying any data/No indication on

No indication

  1. 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.
5. Then switch ON the battery MCB.
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 while keeping SPV MCB OFF.
3. After verifying connections and checking voltage by multimeter switch ON the MCB.
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. Load can be connected at the terminal block marked as output and at the Output socket at the back.
2. Phase terminal of load must be connected to the phase terminal of the system and neutral terminal of load must be connected to the neutral terminal of the system. 
3. Phase terminal is marked as `P` and neutral terminal is marked as `N`.