Showing posts with label charger. Show all posts
Showing posts with label charger. Show all posts
Thursday, November 20, 2014
Automatic Battery Charger Circuit
Basically the circuit designed above have a very simple way of working, where the circuit is designed so that does not happen short circuit or short circuit between the voltage supply with batteries that will be in-charge.
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It is true that if any one wants to try to direct mengghubungkan between supply with batteries then the batteries can be sure will be filled. But the current flowing through a charged battery can not be controlled and if the battery is full, the batteries will be damaged or worn out if it remains on the short circuit condition.
Working Principle Battery Charger
By the time we put an empty battery charging terminals, transistor Q1 will be activated immediately because the current flows through R1 and would trigger a transistor Q1 base. In this condition the flow that would fill the batteries mostly comes from the collector of Q1 is connected directly to the positive terminal of supply. Then during the charging process increases the battery voltage will increase the current flowing in Q2 base via 10 Kohm R5, VR1 and diode D2. VR1 is a component that is used as an initial calibration to determine the exact position in the planning process of switching circuit. For VR1 you can use a trimpot or potensio according to your taste. At the beginning of filling, arrange potensio at position D3 LED indicators on the condition of death, and the current flowing into the collector of Q1 is not too big and not too small.
If the battery is fully charged, the LED indicator will light up automatically because of an increase in voltage on the battery charge will cause the increase of current flowing at the base of transistor Q2 and will terminate the charging cycle due to transistor Q1 having a cut-off due to lack of base current. Why on condition Q1 base current will experience a shortage of this is because almost all the current flowing in R1 10 Kohm will switch to a diode D1 which is logically connected directly with ground experience due Q2 saturated.
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Component List
1. Resistors: R1 (10 Kohm), R2 (680 ohms), R3 (100 Kohm), R5 (10 Kohm) and VR1 (Potensio / trimpot = 100 Kohm)
2. Diodes: D1 & D2 (IN4002) and D3 (Led)
3. Transistors: Q1 and Q2 (2N3904)
4. 9 volt power supply
By the time we put an empty battery charging terminals, transistor Q1 will be activated immediately because the current flows through R1 and would trigger a transistor Q1 base. In this condition the flow that would fill the batteries mostly comes from the collector of Q1 is connected directly to the positive terminal of supply. Then during the charging process increases the battery voltage will increase the current flowing in Q2 base via 10 Kohm R5, VR1 and diode D2. VR1 is a component that is used as an initial calibration to determine the exact position in the planning process of switching circuit. For VR1 you can use a trimpot or potensio according to your taste. At the beginning of filling, arrange potensio at position D3 LED indicators on the condition of death, and the current flowing into the collector of Q1 is not too big and not too small.
If the battery is fully charged, the LED indicator will light up automatically because of an increase in voltage on the battery charge will cause the increase of current flowing at the base of transistor Q2 and will terminate the charging cycle due to transistor Q1 having a cut-off due to lack of base current. Why on condition Q1 base current will experience a shortage of this is because almost all the current flowing in R1 10 Kohm will switch to a diode D1 which is logically connected directly with ground experience due Q2 saturated.
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Component List
1. Resistors: R1 (10 Kohm), R2 (680 ohms), R3 (100 Kohm), R5 (10 Kohm) and VR1 (Potensio / trimpot = 100 Kohm)
2. Diodes: D1 & D2 (IN4002) and D3 (Led)
3. Transistors: Q1 and Q2 (2N3904)
4. 9 volt power supply
Monday, October 20, 2014
Simple Solar Cell Array Charger with Regulator
Solar Cell Array Charger with Regulator circuit can be used to charge batteries from a solar cell array. The circuit consists of an oscillator, a DC-DC step-up or ‘boost’ converter and a regulator that pro-vides regulation of the output voltage.The oscillator is built around a hex Schmitt trigger inverter IC, the 40106B, one resistor, R1, inserted between the input and the output of one of the gates in the 40106 to supply charge to C3. Depending on the values of resistor R1 and capacitor C3 you’re using in the circuit, the oscillator will operate at different frequencies, but a frequency below 100 kHz is recommended.
By consequence, the oscillator frequency should not exceed the maximum ripple frequency of capacitor C2 connected on the output. C2 should be an electrolytic capacitor with a DC working voltage larger than the desired output voltage. Besides, it should have a low ESR (equivalent series resistance).
Solar Cell Array Charger with Regulator Circuit Diagram :
IC1A is used as a buffer, ensuring that the oscillator sees a light, fairly constant load and so guaranteeing that the output frequency remains stable (within limits, of course). VCC of the Schmitt trigger can be connected directly to the battery charged, provided the charged batter y voltage does not exceed the max. or min. limits of the Schmitt trigger’s supply voltage. This ensures the Schmitt trigger can operate even if little power is obtained from the solar cell array.
When transistor T2 is turned on, (output from oscillator buffer IC1A is high), a collector current flows through inductor L1 which stores the energy as a magnetic field and creates a negative voltage VL1. When transistor T2 is switched off, (output from oscillator buffer IC1A is low), the negative voltage VL1 switches polarity and adds to the voltage from the solar cell array. Consequently, current will now flow trough the inductor coil L1 via diode D1 to the load (capacitor C2 and possibly the battery), irrespective of the output voltage level.
Capacitor C2 and/or the battery will then be charged. So, in the steady state the out-put voltage is higher than the input voltage and the coil voltage VL1 is negative, which leads to a linear drop in the current flowing through the coil. In this phase, energy is again transferred from the coils to the out-put. Transistor T2 is turned on again and the process is repeated. A type BC337 (or 2N2222) is suggested for T2 as it achieves a high switching frequency. Inductor L1 should have a saturation current larger than the peak current; have a core material like ferrite (i.e. high-frequency) and low-resistance. Diode D1 should be able to sustain a forward current larger than the maxi-mum anticipated current from the source. It should also exhibit a small forward drop and a reverse voltage spec that’s higher than the output voltage. If you can find an equivalent Schottky diode in the junk box, do feel free to use it.
The most important function of the shunt regulator around T1 is to protect the batteries from taking damage due to overcharging. Besides, it allows the output voltage to be regulated. Low-value resistor R3 is switched in parallel with the solar cell array by T1 so that the current from the solar cell array flows through it. Zener diode D2 is of course essential in this circuit as its zener voltage limits the output voltage when T1 should be turned on, connecting the solar cell array to ground via R3. In this way, there is no input voltage to the boost converter and the battery cannot be overcharged.
Sealed lead-acid (SLA) batteries with a liquid electrolyte produce gas when over-charged, which can ultimately result in damage to the battery. So, it’s important to choose the right value for zener diode D2. Special lead-acid batteries for solar use are available, with improved charge-discharge cycle reliability and lower self-discharge than commercially-available automotive batteries.
Finally, never measure directly on the out-put without a load connected the ripple current can damage your voltmeter (unless it’s a 1948 AVO mk2). Link
Thursday, September 25, 2014
Simplest Automatic Ni Cd Battery Charger Circuit Using IC 555
The 555 timer can conveniently function as the heart of an automatic Ni-Cd battery charger, the circuit is intended to maintain a full charge on a standby battery supply for an instrument that is always connected to the mains, whether in use or not. lt can also be used for the charger unit for pocket calculators, etc.
The circuit uses the timer’s two on-chip comparators, the flip flop and driver amplifier. A zener provides a reference voltage somewhere near the battery voltage with an allowance for adjustment.
The two potential divider networks supply the comparators with adjustable voltages, one for LOW (switch on) and the other for HlGH (switch off). When on, the output gives a maximum of 10V and when off gives GV, the maximum current is 150mA which is limited by the ·47 ohms and protected by the diode. The circuit is calibrated by substituting a variable voltage supply for the Ni-Cd batteries., The HIGH adjustment is set first so that the output switches off at the maximum battery voltage and then the LOW is set for minimum battery voltage. It is simplest to leave the output disconnected from the resistor until after the setting up procedure.
The circuit uses the timer’s two on-chip comparators, the flip flop and driver amplifier. A zener provides a reference voltage somewhere near the battery voltage with an allowance for adjustment.
The two potential divider networks supply the comparators with adjustable voltages, one for LOW (switch on) and the other for HlGH (switch off). When on, the output gives a maximum of 10V and when off gives GV, the maximum current is 150mA which is limited by the ·47 ohms and protected by the diode. The circuit is calibrated by substituting a variable voltage supply for the Ni-Cd batteries., The HIGH adjustment is set first so that the output switches off at the maximum battery voltage and then the LOW is set for minimum battery voltage. It is simplest to leave the output disconnected from the resistor until after the setting up procedure.
Monday, September 15, 2014
USB Battery Charger for Lithium Ion Battery
This schematic diagram is used for charging lithium ion battery. The power source is from a computers USB port. With this schema, you do not need to build power supply diagram for charging your battery.
A USB port is a great power source for charging a single cell li-on battery. It is capable of supplying maximum 5.25V and 500 mA. The schema above is a USB powered single cell li-on battery charger. LM3622 is used as the controller. This special purpose IC has a precise end-of-charge control and low battery leakage current about 200nA.
Wednesday, September 3, 2014
Solar Energy Powered an iPhone Battery Charger
The project was termed as Mighty Minty Boost as it was developed to function as iPod/iPhone charger with solar power. Aside from being small, it has a large battery capacity of 3.7V at 2000mAh and it accepts input power from 3.7V to 7V. As shown in the images below, it can become a compact USB power supply when the solar cell is removed after charging. The Velcro is used to secure the Mighty Minty Boost inside a backpack or messenger bag after unplugging the solar cell.
For faster charging, a larger solar cell can be attached to the bag. Enough power can be generated to fully charge an iPhone in about 5.5 hours and an iPod Touch in 4 hours using a slightly larger solar cell with 6V at 250mAh. The charger will automatically switch to trickle charging when the cell reaches full charge. The charging current is limited to 100mA when charging using the mini USB port and the charging is limited to 280mA when charging using the barrel plug jack
For faster charging, a larger solar cell can be attached to the bag. Enough power can be generated to fully charge an iPhone in about 5.5 hours and an iPod Touch in 4 hours using a slightly larger solar cell with 6V at 250mAh. The charger will automatically switch to trickle charging when the cell reaches full charge. The charging current is limited to 100mA when charging using the mini USB port and the charging is limited to 280mA when charging using the barrel plug jack
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The materials needed to build the charger include a small solar cell, Lithium Polymer battery charger, minty boost kit, adhesive backed Velcro, Altoids tin, connector/wire, and small double adhesive squares as shown in the images below. An input power that ranges from 3.7V to 7V maximum can be accepted by the single cell Lithium Polymer. In bright sunlight, the solar cell maxes out at approximately 5V at 100mA. A larger solar cell with 6V at 250mA can be used for faster charging.
The images below show the assembly of minty boost kit where a JST connector is soldered to the minty boost PCB instead of connecting the battery holder in the kit. The minty boost schema is allowed to connect to the Lithium Polymer battery charger schema with this tiny connector. The minty boost is tested by connecting the battery pack and the charger schema, the Lithium Polymer battery connects to the connector marked GND on the charger board and the minty boost connects to the connector marked SYS.
To fit the charger, a notch is cut out of the other side of the Altoids tin and used double sided adhesive to secure the charging schema to the bottom of the Altoids as shown below. The bottom of either one of the schema boards should not touch the bottom of the Altoids tin while reconnecting the minty boost PCB and the battery to the charging schema.
Connecting or adding the solar cell can be done in different ways. Shortening the connector leads and plugging the barrel plug into the barrel jack on the charging schema is one way. The other method is using another JST connector to replace the connector and plugging it into the third connector marked 5V on the charging schema. Since there is no bog barrel plug sticking out of the side of the tin, using the second method is cleaner.
As shown in the photos below, some 2” Velcro was used to attach the solar cell to the top of the Altoids. To help protect the battery, a layer of clear packing tape was used for wrapping. N top of the two schema boards, the battery pack is then set down. A red LED on the charger board will light up when the Mighty Minty Boost is set out in the bright sun. The iPod/iPhone/USB powered device can be connected once it is fully charged.
Sunday, August 31, 2014
Car Mobile Phone Charger Circuit
Cellphone battery charging process when were done traveling is a big problem. Because when traveling source of power supply is generally difficult to find. If you turn on your phone then the battery continuously over time will run out within a period of five to six hours and eventually mobile phones unusable. Here is described a series of simple charger that will increase battery life two to three hours.
In principle, the charger uses a series of Limited Voltage Current Source. Generally requires cellphone battery voltage 3.6 - 6 volts DC and currents 180-200 mA to perform the charging process. Cellphone battery usually consists of three NiCd battery cells, and each cell has a voltage of 1.2 volts potential. At the speed - average low flows required to charge mobile phone battery about - about 100mA.
In this series there is a 12V voltage source consists of 8 regular battery cells (each cell 1.5 Volt) able to supply current at 1.8 A which is connected with output terminals.
The circuit is also able to monitor the battery voltage level which is in charge. And will automatically cut off the charging process when the output terminal detects a certain battery voltage level predetermined. Timer IC NE555 is used to charge and monitor the voltage level in the battery, Pin 5 (IC1) as the control voltage using a reference voltage zener voltage 5.6Volt. Voltage at Pin 6 as the threshold set by VR1 and the voltage at Pin 2 as the trigger is set by VR2.
When the cellphone battery is connected in series (the Charging Process) applied voltage on PIN2 (IC1) as a trigger would be below the value 1 / 3 Vcc and will cause the Flip-Flop in IC1 will ON and on Pin 3 (IC1) will be high (Cause transistor T1 saturation.). When the battery is full (Full Charge) then the voltage will rise and the voltage on the PIN2 (IC1) will be above the level of trigger point threshold. This will cause the Flip Flop OFF and the output will be low (transistor T1 causes the cutoff) and indirectly also the charging process will stop.
Pin 6 (Threshold IC1) is set at 2 / 3 Vcc by using VR1, transistors T1 which is used to increase the charging current. R3 value is very important to provide the charging current, by setting the value of R3 to 39 ohms then the charging current supplied approximately 180mA. This circuit can be built on any type of PCB (General Purpose PCB) for the calibration process using the DC voltage level cutoff Variable Power Supply. Connect the output terminal circuit with Variable DC Power Supply and set on 7 volts. Adjust VR1 in middle position and slowly adjust VR2 until LED1 OFF, this indicates Low Output. LED1 should turn on when the DC Variable Power Supply voltage is reduced below 5V. LED1 Status flame shown in the table below. Closed circuit with plastic casing and use a suitable connector for connecting to the Battery for Mobile.
Thursday, August 21, 2014
5v Powered Charge Pump Battery Charger
The schema below will trickle charge a four cell pack of AA or AAA NiMH batteries. The schema draws current from the +5v available a USB connection and pumps about 70ma of current into the battery. This should be enough current to fully charge a pack of 2500ma-hour cells in about 36 hours. The schema uses a single 74HC14 hex Schmitt trigger inverter in conjunction with a voltage doubler charge pump schema.
5v Powered Charge Pump Battery Charger Circuit Diagram
Source: DiscoverCircuits
Thursday, August 14, 2014
Universal battery charger with 12V source voltage
In this post I will share about using Accu source to charge batteries that can be used on any mobile brand, or can be called universal phone battery charger. Because the battery charger using a source of 12V, the charge accumulator can also be used in cars and others.
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Wednesday, August 13, 2014
Solar Charger for Lead Acid Batteries
This schema is still under development, but works well as shown.
This schema is intended for charging lead-acid batteries with a solar panel. The customary diode that prevents the battery from discharging through the solar panel has been replaced by a FET-comparator combination. The charger will stop charging once a pre-set voltage (temperature compensated) has been reached, and recommence charging when the voltage has dropped off sufficiently. The load is disconnected when the baterry voltage drops below 11V and reconnected when it gets back to 12.5V.
The schema has the following features:
- Charges until Vbat = 13,8V (adjustable), then float charges;
- Shuts down load when Vbat < 11V (adjustable), resets at 12,5V;
- Temperature compensation;
- Will work with cheap and readily available components like LM393 comparators and BUZ11 FETs;
- Uses less than 1.3mA (Attempts to use micropower comparators have failed spectacularly so far, see below);
- Burns less than 20mW in FETs when charging at 0,5A. (More expensive FETs with a lower RDSON will yield even better results).
Note that the charging current is limited only by the solar panel used.
Heres the schema:
Note the funny place of grounding of the first 2 comparators. Theres some weirdness here: this bit of the schema gives me headaches. Two problems:
- If I ground the first two comparators (LM393) in the same place as the third, i.e. not between the FETs, the thing wont work and the battery will discharge over the solar panel. Why? Am I playing to close to the rails? How can this be remedied/improved/redesigned? Do I need a diode between the comparators imputs?
- If I use micropower comparators like the Texas Instruments TLC393, the comparators blow up spectacularly, but with the standard LM393 everything works fine. Why? What did I miss?
Help would be greatly appreciated!
Next attempt
This one works fine and uses about 0.5mA, but that might improve because Im not done tweeking yet:
by Oscar den Uijl, odu@xs4all.nl
Saturday, August 9, 2014
12V Battery Charger
This schema is a high-performance charger for gelled-electrolyte lead-acid batteries. This charger quickly recharges the battery and shuts off at full charge. Initially, charging current is limited to 2 A. As the battery voltage rises, current to the battery decreases, and when the current has decreased to 150 mA, the charger switches to a lower float voltage, which prevents overcharge.
Circuit diagram :
12V Battery Charger Circuit Diagram
When the start switch is pushed, the output of the charger goes to 14.5 V. As the battery approaches full charge, the charging current decreases and the output voltage is reduced from 14.5 V to about 12.5 V, terminating the charging. Transistor Q 1 then lights the LED as a visual indication of full charge.
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