Dear All,
I have installed a PWM Solar Charge Controller for a off-grid street light system. Where specs are as follows: LiFePO4 25.6V Battery 60 Ah, Streetlight = 30W (rated to operate at Vin: 16-32 V DC), Charge Controller I have made is PWM charge Controller which is designed as per 24V System i.e. Panel's Max Voc= 44V DC. Panel used = 200W Voc= 44V, Vmp= 36V, Imp= 5.5 Amps.
My PWM charge controller has Transistor and Zener Diode based Linear Voltage Regulator to generate 15V stable voltage from Panel's Connection (0-44V DC) for using it in Gate Control of the Charging Mosfet (N channel Mosfet Vgs≤ 20V). Mosfet Vds= 100V, Id= 110A.
NPN Transistor Used for Voltage Regulation= BD139 i.e. 80V (Vcbo & Vceo) 1.5A (Ic) NPN Transistor. Zener Diode = 15V / 1W.
The Voltage Regulator (of Transistor) has 6.8k Ohms resistor in series after output of +15V before it goes to switching circuit for Mosfet. Thus the power rating of transistor is always under limit. The Base Resistor of NPN Transistor is 20k Ohms where Zener is attached in reverse bias to ground (Panel -ve).
Now this system is working well in other locations from almost last 1.5 to 2 years but in one system the transistor which regulates 15V is getting burnt repeatedly. Only strange situation is, that suspected system is close to a High Voltage Transmission Line which is passing in near vicinity of the garden where the system is installed.
Also what I have noticed it that my Charge Controller don't have MOV (Varistor) of 45-60V DC which many manufacturer use at the Panel +ve & -ve connections in charge controller to withstand / bypass the surge from Panel Side. I am unaware of this type of surge from Panel side in off-grid system.
If anyone has some data regarding same or any International Standards to test the charge controller with respect to surge from Panel Side then please share the same.
For now I am not considering the impact of the HV line passing nearby but is there any other possibility of the transistor getting damaged ?.
I know it is an electronic cum Solar based question, I am not sure if this should be in thid forum or not but I would appreciate your valuable input, Thank you in advance.
I have installed a PWM Solar Charge Controller for a off-grid street light system. Where specs are as follows: LiFePO4 25.6V Battery 60 Ah, Streetlight = 30W (rated to operate at Vin: 16-32 V DC), Charge Controller I have made is PWM charge Controller which is designed as per 24V System i.e. Panel's Max Voc= 44V DC. Panel used = 200W Voc= 44V, Vmp= 36V, Imp= 5.5 Amps.
My PWM charge controller has Transistor and Zener Diode based Linear Voltage Regulator to generate 15V stable voltage from Panel's Connection (0-44V DC) for using it in Gate Control of the Charging Mosfet (N channel Mosfet Vgs≤ 20V). Mosfet Vds= 100V, Id= 110A.
NPN Transistor Used for Voltage Regulation= BD139 i.e. 80V (Vcbo & Vceo) 1.5A (Ic) NPN Transistor. Zener Diode = 15V / 1W.
The Voltage Regulator (of Transistor) has 6.8k Ohms resistor in series after output of +15V before it goes to switching circuit for Mosfet. Thus the power rating of transistor is always under limit. The Base Resistor of NPN Transistor is 20k Ohms where Zener is attached in reverse bias to ground (Panel -ve).
Now this system is working well in other locations from almost last 1.5 to 2 years but in one system the transistor which regulates 15V is getting burnt repeatedly. Only strange situation is, that suspected system is close to a High Voltage Transmission Line which is passing in near vicinity of the garden where the system is installed.
Also what I have noticed it that my Charge Controller don't have MOV (Varistor) of 45-60V DC which many manufacturer use at the Panel +ve & -ve connections in charge controller to withstand / bypass the surge from Panel Side. I am unaware of this type of surge from Panel side in off-grid system.
If anyone has some data regarding same or any International Standards to test the charge controller with respect to surge from Panel Side then please share the same.
For now I am not considering the impact of the HV line passing nearby but is there any other possibility of the transistor getting damaged ?.
I know it is an electronic cum Solar based question, I am not sure if this should be in thid forum or not but I would appreciate your valuable input, Thank you in advance.