Introduction
In July 2021 challenge of EFY, article “Solar Pooja Lamp That Runs Nonstop” was printed. It makes use of supercapacitors to energy LEDs within the evening. In FEB 2023 challenge of EFY, “POWER SUPPLY FOR A CLOCK Using Supercapacitor And Small Solar Panels” was printed.
Right here, an improved Pooja Lamp is proposed with 32 additional LEDs (5 mm 20 mA) to get extra gentle within the day time. Additional, clock energy provide circuit is built-in, which drives two wall clocks. The facility provide circuit attracts energy from the identical PV panel used for Pooja Lamp.
System runs continuous for 15 years without having a lot consideration. It might preserve edible oil and get rid of AA batteries. This can be a very cost-effective and enticing mixture and is anticipated to spice up demand for supercapacitors.
Improved Pooja Lamp
Circuit diagram of improved Pooja Lamp is proven in Fig. 1. It consists of two PCBs. PCB_L for Left lamp and PCB_R for Proper lamp. In every PCB, one 500 F supercapacitor is accommodated. These PCBs are mounted on the backside part of two silver lamps. For interconnections between the 2 PCBs, 8 pin polarized headers (CON_L, CON_R) have been used. A ten W Photo voltaic PV panel (17.5V Vmp, 580mA) is used to energy the circuit.
Word that, within the circuit diagram the screw terminals are proven by black bullets. The indicators going to the 8 pin headers are proven by triangles. Desk 1 exhibits the interconnections between CON_L and CON_R. The jumper cable is made by doing one-to-one pin connections utilizing two 8 pin housings.
| Node Identifier | EL+ | EL- | A | B | Vc | JL+ | JL- |
| Node Identifier | ER+ | ER- | A | B | Vc | JR+ | JR- |
| CON_L, CON_R pins | 1 | 2 | 3 | 4 | 5 | 6 | 7, 8 |
Recap of Pooja Lamp
LED1 to LED10 are 1 W orange LEDs which flip ON throughout day time. 5 of those LEDs are related in collection for every lamp and their present is restricted by resistors R1 and R2 (27Ω 1W). The present flowing by these resistors flows by D1 (1N5819) and expenses supercapacitors C1 and C2 (500 F 2.7V). Resistor R3 (0.33Ω) and Zener Diode ZD1 (2.7V 1W) limits the supercapacitor voltage to 2.7V. Additionally, diode D2 (1N5819) and D3 (6A4) and LED11 to LED26 (Orange 5mm 20mA) stop C1 and C2 from getting overcharged. Word that, all these 16 LEDs are related in parallel (OM) and these flip ON solely when the supercapacitors are absolutely charged. Charging time of those capacitors might vary from 2 to 4 hours relying upon the daylight depth.
Within the evening, the vitality saved within the capacitors is utilized by the Joule Thief circuit made utilizing transistor T1 (BC547C), and Toroidal transformer TCT1 (50:50 turns, 32 mm diameter). It powers LED27, LED28 and LED29, LED30. These LEDs are 5mm 20 mA superbright white LEDs which maximize gentle output. Within the day time, the PV voltage sensing circuit consisting of transistor T2 (BC546), resistors R5 (6.8kΩ) and R6 (1kΩ) cease the joule thief circuit from oscillating. When PV voltage does down within the night, the Joule Thief circuit begins functioning.
Ideas for Toroidal Transformer: For the first winding, a thicker enameled wire is advisable, eg SWG 20. For secondary a really skinny wire might be chosen eg SWG 30. It will be sure that each windings might be wound in single layer. Additionally, we are able to improve the variety of turns as much as 80 turns. (major and secondary variety of turns must be equal). Growing the variety of turns will barely scale back losses in T1.
Additional LEDs
LED101 to LED132 (Inexperienced 5 mm 20 mA) are all related in parallel. These are grouped in two rings of 16 every. One ring is mounted on the left lamp, the opposite on the suitable lamp. These LEDs are inserted between PV+ and LL+ (and LL-) nodes. Which introduces ahead voltage drop of 1 LED. Even after inserting these additional LEDs, the efficiency of authentic pooja lamp just isn’t affected. The reason is, PV panel voltage will increase by ahead voltage drop of 1 LED, as a result of PV panel acts as present supply. The Pooja Lamp voltage stays similar for given depth of photo voltaic radiation.
Equation for PV voltage when C1 and C2 are absolutely discharged is as follows:
Vpv = VLED(G) + [5 * VLED(Or)] + VR1 + VD1
18V = 2.75V + 5 * 2.1V + VR1 + 0.3V
Drop throughout R1 = VR1 = 4.45 V
Present by R1 = 4.45V / 27Ω = 165 mA
Equally, 165 mA present flows by R2.
Present by particular person inexperienced LEDs = 165/16 = 10.31 mA
Thus, present in every inexperienced LED is about 10 mA. Which is inside the max present ranking.
Choice of Additional LEDs: Since all 32 LEDs are related in parallel, it’s needed to make sure that all these LEDs have matching ahead voltage. So that every one LEDs will present uniform gentle depth. On this design, inexperienced LEDs have been chosen. Nevertheless, consumer can choose every other coloration. The ahead voltage of particular person LEDs might be measured by making a easy take a look at circuit. To a 5 V adaptor optimistic terminal, join 220Ω present limiting resistor on a bread board. Join LEDs between resistor and the bottom, one after the other and measure the ahead voltage of every LED. Group the LEDs having similar ahead voltage. A small variation of ± 0.1 V is appropriate.
Determine 2 exhibits two assembled PCBs with one supercapacitor mounted on every of them. The screw terminals are soldered on one facet of the PCB. The varied connections to be made to those terminals have been recognized. 8 pin headers are soldered to every of the PCBs for interconnections between the 2 PCBs. These PCBs are mounted within the cavities on the backside part of small silver lamps. For connections to the LEDs mounted on the lamp, use of very skinny (7/42) white wires. These are simply obtainable available in the market.
Single Lamp
It’s potential to make one single larger lamp to accommodate the total circuit of Fig. 1. On this case, the 8 pin headers are eliminated and the nodes recognized in every column of Desk 1 are shorted. Fig 3 exhibits the {photograph} of single PCB design. Word that nodes LL+ and LL- merged and named as L+. Equally, EL+ and ER+ merged as E+, EL- and ER- merged as E-, JR+ and JL+ as J+.
Fig 4 exhibits the 2 supercapacitors assembled lengthwise and related in parallel. This meeting is mounted within the vertical area obtainable on the backside part of the large lamp. PCB is fastened on the base in order that capacitor meeting will get help on the middle of this PCB.
Fig 5 (a) exhibits the large lamp with all of the day gentle LEDs turned on. Two rings of inexperienced LEDs are mounted on the underside part of this lamp. Fig 5 (b) exhibits two small lamps with the day gentle LEDs turned on. For every lamp one inexperienced led ring is mounted at their backside sections.
Fig 6 exhibits white LEDs turned ON throughout evening, with the assistance of joule thief circuit. On the left facet, single lamp has 4 white LEDs. On the suitable facet, for the 2 lamps 2 white LEDs every are ON.
Integration of clock energy provides
As talked about within the article on Clock Energy Provide, the wall clocks want very small energy. Which might be tapped from the PV panel used within the Pooja Lamp. I addition, we’d like a supercapacitor to drive the clock throughout evening. Nevertheless, we cannot use the supercapacitors used within the Pooja Lamp. The reason is, the joule thief circuit makes use of all of the vitality saved in these capacitors by out the evening. The capacitor voltage within the early morning drops under 1 volt. Clock minimal working voltage is 1 volt. Therefore, we have to use a devoted supercapacitor for the clock driver circuit. The design of this circuit is given under:
Design of Clock1 energy provide
Determine 7 exhibits the facility provide circuit for the Clock1. It consists of a supercapacitor C101 (100F 2.7V). It’s related by diode D101 (1N5819) to node A of the Pooja Lamp circuit (see Fig.1). Node A provides charging present to C101. Additionally, the over charging safety circuit consisting of D1 & ZD1 and D2, D3 and LED11-LED26 additionally supplies safety to C101 towards overcharging.
Supercapacitor is related to the +Vclock1 terminal by present limiting resistor R101 (220Ω). A filter capacitor C102 (4700µF 10V) is related throughout the clock terminals. Diodes D102, D103 and D104 (1N4007) are additionally related to clamp the voltage under 2V. Throughout C101 a 2 pin polarized connector header CON1 is related. This connector supplies energy to the second clock driver circuit as defined under.
Design of Clock2 energy provide
Determine 8 exhibits the circuit diagram of Clock2 energy provide circuit. It consists of two pin connector header CON2. A 2 pin jumper cable is used to faucet the facility from Clock1 PCB to Clock2 circuit. Present limiting resistor R102 (220Ω) is related from CON2 to +Vclock2 terminal of the second clock. Additionally, filter capacitor C103 (4700µF 10V) and clamping diodes D105, D106 and D107 (1N4007) are related throughout clock2 terminals. Word that this circuit makes use of the vitality saved in C101. There is no such thing as a want of extra supercapacitor for Clock2, thus decreasing the price and dimension of this PCB.
Fabrication and Interconnections
Determine 9 exhibits the assembled PCBs for Clock1 and Clock2. These PCBs need to be stored close to to the respective clocks as a result of the filter capacitors must be near them. Run a cable from terminals A and PV- (see Fig. 3) to the respective terminals of Clock1 PCB. There is no such thing as a restriction on the size of this cable. Make a 2 pin Jumper of required size and interconnect the 2 PCBs. Once more, there isn’t a size restriction for this jumper cable. Join the outputs of those PCBs to respective clocks. For making all these cables very skinny wires (7/42) can be utilized, that are simple to hide.
Conclusion
An built-in system consisting of Photo voltaic Pooja Lamp and Clock energy provides is proposed right here. It makes use of supercapacitors to retailer vitality, for powering the lamps and clocks throughout evening time. These capacitors can deal with day by day cost and discharge cycles and are setting pleasant. They’ve 15 years of life. This built-in system can discover use in each home and has potential to avoid wasting great amount of cooking oil and get rid of AA cells all through the lifetime of the clocks. It will get rid of hazardous chemical waste. The consumer can have the satisfaction of utilizing photo voltaic vitality of their houses.
