These days solar panels and PV cells have grown to be very well liked and in the near future we could quite possibly observe everyone of us utilizing it in a few or the other way in our life. One crucial utilization of these devices continues to be in the field of street lighting. The following article talks about one such fascinating circuit which widely describes the providing of a 40 watt fully automatic solar street light system circuit (specifically manufactured by me).
The circuit which includes already been mentioned here has the majority of the normal specs offered with it, the following data clearly shows it a lot more elaborately:
LED Lamp Features
Voltage: 12 volts (12V/26AH Battery)
Current Consumption: 1.4 Amps @13 volts, and 1.2 Amps @12V
Power Consumption: 1.2 * 12 = 14.4 watts, (comparable to light provided by 39 watt LED lamp)
Light Intensity: Somewhere around 2000 lm(lumens)
Input: 32 volts from a solar panel stipulated with around 32 volts open circuit voltage, and short circuit current of 5 to 7 Amps.
Output: Max. 14.3 volts, current restricted to 4.4 Amps
Battery Full - Cut OFF at 13.98 volts (set by P2).
Low Battery - Cut OFF at 11.04 volts (set by P1).
Battery charged at C/5 rate with float voltage limited to 13.4 volts after “battery full cut OFF”.
Automatic Day/Night Switching with LDR Sensor (set by choosing R10 appropriately).
Within this initial section of the post we are going to analyze the solar charger/controller phase and the related over/low voltage cut-off circuit, as well as the automatic day/night cut-off section.
R1, R3,R4, R12 = 10k
R5 = 240 OHMS
P1,P2 =10K preset
P3 = 10k pot or preset
R10 = 470K,
R11 = 100K
R8=10 OHMS 2 WATT
T1----T4 = BC547
A1/A2 = 1/2 IC324
ALL ZENER DIODES = 4.7V, 1/2 WATT
D1---D3,D6 = 1N4007
D4,D5 = 6AMP DIODES
IC2 = IC555
IC1 = LM338
RELAYS = 12V,400 OHMS, SPDT
BATTERY = 12V, 26AH
SOLAR PANEL = 21V OPEN CIRCUIT, 7AMP @SHORT CIRCUIT.
Solar Charger/Controller, High/Low Battery Cut OFF and Ambient Light Detector Circuit Stages:
Talking about the circuit diagram above, the panel voltage is controlled and maintained to the needed 14.4 volts by the IC LM 338.
P3 is utilized for setting the output voltage to precisely 14.3 volts or somewhere near to it.
R6 and R7 forms the current reducing parts and ought to be determined properly as talked about Right here.
The under control voltage is following placed on the voltage/charge control and the connected steps.
Two opamps A1 and A2 are connected with converse configurations, which means the output of A1 turns into high when a preset over voltage value is identified, while the output of A2 turns out high on detection of a specific low voltage guideline.
The above high and low voltage thresholds are correctly set by the fixed P2 and P1 respectively.
Transistors T1 and T2 reply appropriately to the above outputs from the opamps and triggers the specific relay for managing the charge levels of the associated battery with regards to the presented guidelines.
The relay attached to T1 in particular manages the overcharge limit of the battery.
The relay hooked up to T3 is liable for holding the voltage to the LED lamp phase. Providing the battery voltage is above the low voltage limit and provided that no ambient light occurs around the system, this relay maintains the lamp turned on, the LED module is immediately turned OFF in the event the required problems are not finished.
IC1 together with the connected elements forms the light detector circuit, its output goes high in the existence of ambient light and vice versa.
Believe it's day time and a partially discharged battery at 11.8V is attached to the appropriate points, also believe the high voltage cut off to be set at 14.4V. On power turn on (either from the solar panel or an external DC source), the battery will begin charging via the N/C contacts of the relay.
Since it's day, the output of IC1 is high, which switches ON T3. The relay hooked up to T3 holds the battery voltage and prevents it from achieving the LED module and the lamp stays shut OFF.
As soon as the battery gets completely charged, A1's output goes high activating T1 and the linked relay.
This disconnects the battery from the charging voltage.
The above scenario latches ON with the aid of the feedback voltage from the N/O contacts of the above relay to the base of T1.
The latch continues until the low voltage situation is attained, when T2 switches ON, grounding T1's base biasing and reverting the top relay into the charging mode.
Within the next Post we can easily talk about the PWM managed, easy LED lamp module and discover how the above circuit is built-in along with it.