eSyndiCat Directory v2.3.05

Charger Extends Lead-Acid Battery Life

Sat, 30 Mar 2013 00:03:00 MST

The circuit furnishes an initial charging voltage of 2.5 V per cell at 25Â°C to rapidly charge a batt

Battery charger with LM317

Mon, 25 Mar 2013 00:03:00 MST

An LM317 voltage regulator is configured as a constant-current source. It is used to supply the 50 mA charging current to S01-S06, an array of AA-cell battery holders. Each of the battery holders is wired in series with an LED and its associated shunt resistor. When the battery holder contains a battery, the LED glows during charging. Each battery holder/LED combination is paralleled by a 5.1-volt Zener diode. If the battery holder is empty, the Zener conducts the current around the holder.

Battery-Temperature Sensing Nicad Charger

Tue, 19 Mar 2013 00:03:00 MST

Two simple circuits permit Nicad charging of a battery based on temperature differences between t

Ni-cad charger

Sun, 17 Mar 2013 00:03:00 MST

This circuit uses constant current LEDs to adjust charging current. It makes use of LEDs that pass a constant current of about 15 mA for an applied voltage range of 2-18 V. They can be paralleled to give any multiple of 15 mA and they light up when current is flowing

Intelligent Battery-Charging Circuit Circuit

Sat, 16 Mar 2013 00:03:00 MST

Intended for a Nicad application this charging circuit can be used with a wide range of batteries. A low-battery detector is intended. The trip voltage is set via the 500-kQ pot.

Ni-Cd Baterry Charger 12-18V

Thu, 28 Feb 2013 00:02:00 MST

A clever charger circuit that safely can charge any Ni-Cd battery. Offers charge current sellection, polarization detection and protection and the ability to connect many batterys in siries. Ni-Cd bateries can be recharged more than 1000 times before become useless. the charging current shoud be the 1/10 of the (Ah) of the battery. The bateries need 14 hours to be fully charged..

Battery charge-discharge indicator

Sat, 16 Feb 2013 00:02:00 MST

This circuit monitors car battery voltage. It provides an indication of nominal supply voltage as well as low or high voltage. RV1 and RV2 adjust the point at which the red/yellow and yellow/green LEDs are on or off. For example the red LED comes on at 11V, and the green LED at 12V

Ni-cad charger with current and voltage limiting

Wed, 13 Feb 2013 00:02:00 MST

Lamp LI will glow brightly and the LED will be out when the battery is low and being charged, but the LED will be bright and the light bulb dim when the battery is almost ready. Ll should be a light bulb rated for the current you want (usually the battery capacity divided by 10). Diode D1 should be at least 1 A, and Z1 is a 1W zener diode with a voltage determined by the full-charge battery voltage minus 1 V

Lithium battery indicator

Mon, 11 Feb 2013 00:02:00 MST

State-of-Charge indication of-a sloping-voltage discharge can be used as a state-of-charge indicator. A typical voltage comparator circuit that gives a visual indication of state-of-charge is shown.

Universal-battery-charger

Sun, 10 Feb 2013 00:02:00 MST

The charger"s output voltage is adjustable and regulated, and has an adjustable constant-current charging circuit that makes it easy to use with most NiCad batteries. The charger can charge a single cell or a number of series-conoected cells up to a maximum of 18 V. Power transistors Ql and Q2 are conoected as series regulators to control the battery charger"s output voltage and charge-current rate. An LM317 adjustable voltage regulator supplies the drive signal to the bases of power transistors Ql and Q2.

Rapid battery charger

Wed, 23 Jan 2013 00:01:00 MST

Rectified and filtered voltage from the 24 Vac transformer is applied to the LM723 voltage regulator and the npn pass transistor set up for constant current supply. The 470 ohm resistor limits trickle current until the momentary pushbutton (S2) is depressed, the SCR turns on and current flows through the previously determined resistor network limiting the charging current.

Battery charger

Wed, 16 Jan 2013 00:01:00 MST

A diac is used in the gate circuit to provide work for the signal being applied to the gate. R1 a threshold level for firing the triac. C3 and R4 is selected to limit the maximum charging cur-provide a transient suppression network

Charger circuit V

Thu, 03 Jan 2013 00:01:00 MST

The charger is based on a charging voltage of 2.4 V per cell, in accordance with most manufacturers' recommendations. The circuit pulses the battery under charge with 14.4 V (6 cells ? 2.4 V per cell) at a rate of 120 Hz. The design provides current limiting to protect the charger's internal components while limiting the charging rate to prevent damaging severely discharged lead-acid batteries. The maximum recommended charging current is normally about one-fourth the ampere-hour rating of the battery.

Single cell charger

Fri, 14 Dec 2012 00:12:00 MST

This circuit detects a full-charge state and automatically switches to a float conditionâ€”from 240 mA to 12 mA.

Equipment on reminder

Mon, 03 Dec 2012 00:12:00 MST

Due to the low duty cycle of flashing LED, the average current

Heavy duty battery charger

Tue, 13 Nov 2012 00:11:00 MST

Operation amplifier A1 directly drives the VN64GA with the error signal to control the output voltage. Peak rectifier Dl, CI supplies error amplifier A1 and the reference zener. This extra drive voltage must exceed its source voltage by several volts for the VN64GA to pass full load current. The output voltage is pulsating dc which is quite satisfactory for battery charging. To convert the system to a regulated dc supply, capacitor C2 is increased and another electrolytic capacitor is added across the load. The response time is very fast, being determined by the op-amp.

200Ma-12v ni-cad battery charger

Sun, 11 Nov 2012 00:11:00 MST

This circuit charges the battery at 75 mA battery can be left in the charger indefinitely, until the battery is charged, then it reduces the To set the shut-off point, connect a 270-ohm, current to a trickle rate

Wind battery Charger

Fri, 09 Nov 2012 00:11:00 MST

The dc motor is used as a generator with the voltage output being proportional to its rpm. The LTC1042 monitors the voltage output and provides the following control functions. If generator voltage output is below 13.8 V, the control circuit is active and the Ni-Cad battery is charging through the LM334 current source. The lead acid battery is not being charged. If the generator voltage output is between 13.8 V and 15.1 V, the 12 V lead acid battery is being charged at about 1 amp/hour rate (limited by the power FET).

Relay Fuse For Battery Charges Circuit

Mon, 08 Oct 2012 00:10:00 MST

Charged capacitor C3 and momentary pushbutton switch S2 are used to momentarily energize relay RE 2. The batteiy under charge energizes the relay to hold it closed.

12Vdc Mobile Battery Charger

Tue, 18 Sep 2012 00:09:00 MST

This circuit provides up to 20 V output from a 12-V automotive supply, to enable constant current charging o

Portable-nicad-battery-charger

Mon, 27 Aug 2012 00:08:00 MST

This circuit was designed to charge NiCad battery packs in the range of 4.8 to 15.6 V from a convenient remote power source, such as an automobile battery. When power is first applied to the circuit, a small bias current supplied by Rl via winding Wl, starts to turn on the transistor TRl. This forces a voltage across W2 and the positive feedback given by the coupling of Wl and W201uses the transistor to turn hard on, applying the full supply across W2.

Automatic shutoff battery charger

Sat, 25 Aug 2012 00:08:00 MST

Adjust by setting the 500 ohm resistor while attached

Ujt-battery-charger

Mon, 20 Aug 2012 00:08:00 MST

This circuit will not work unless the battery to be charged is connected with proper polarity. The battery voltage controls the charger and when the battery is fully charged, the charger will not supply current to the battery. The battery charging the current is obtained through the SCR when it is triggered into the conducting state by the UJT relaxation oscillator.

Rf-Type Battery Charger Circuit

Wed, 15 Aug 2012 00:08:00 MST

This type of charger couples RF from L2 to an external pickup coil. The pickup coil connects to a rectifier and battery to be charged. This idea is handy because no wire or contacts are required. L2 is 10T #24 wire and L3 is 10T #30 wire.

Battery charging regulator

Thu, 09 Aug 2012 00:08:00 MST

The circuit is capable of charging a 12 volt component selection. When the battery voltage battery at up to a six ampere rate

Portable Nicad Charger

Sat, 04 Aug 2012 00:08:00 MST

The portable charger is intended primarily to give model enthusiasts the opportunity of charging their Nicad batteri

Fast charge Controller with MAX712 / MAX713

Tue, 24 Jul 2012 00:07:00 MST

The MAX712 and MAX713 are nickel cadmium (Ni-Cd) battery fast charge controllers which will fast charge batteries from a DC source at least 1V higher than the maximum battery voltage. 1 to 16 series cells can be charged at rates up to 4C. A voltage-slope detecting analogue-to-digital converter, timer, and temperature window comparator determine charge completion. The MAX712 or 713 are powered by the DC source via an on-clip +5V shunt regulator, and draw a maximum of 5uA from the battery when not charging. A low-side current-sense resistor allows the battery charge current to be regulated while still supplying the power to the battery's load.

Lithium charger circuit

Sat, 14 Jul 2012 00:07:00 MST

Charging is accomplished with a constant current of 60 mA for AA cells to a cutoff voltage of 2.4 V per cell at which point the charge must be terminated. The charging system shown is designed for multi-cell battery packs of 2 to 6 series-connected cells or series/parallel arrangements. It is essential that all cells assembled in the pack be at an identical state-of-charge (voltage) prior to charging.

Simple ni-cad battery zapper

Sat, 30 Jun 2012 00:06:00 MST

This circuit is used to clear internal shorts in nickel cadmium batteries

Put-battery-charger

Mon, 18 Jun 2012 00:06:00 MST

A short-circuit-proof battery charger will provide an average charging current of about 8 A to a 12-V lead/acid storage battery. The charger circuit has an additional advantage; it will not function nor will it be damaged by improperly connecting the battery to the circuit. With 115 V at the input, the circuit commences to function when the battery is properly attached. The battery provides the current to charge the timing capacitor Cl used in the PUT relaxation oscillator. When Clcharges to the peak point voltage of the PUT, the PUT fires turning the SCR on, which in tum applies charging current to the battery.

Simple ni-cad battery charger

Sun, 10 Jun 2012 00:06:00 MST

This circuit provides an adjustable output voltage up to 35 Vdc and maximum output current of 50 mA

NiCad Charger with temp control

Thu, 07 Jun 2012 00:06:00 MST

One way to charge Ni-Cad batteries rapidly without abuse is to measure cell temperature and taper the charge accordingly. The circuit uses a thermocouple for this function. A second thermocouple nulls out the effects of ambient temperature. The temperature difference between the two thermocouples determines the voltage which appears at the amplifier's positive input. As battery temperature rises, this small negative voltage (1Â°C difference between the thermocouples equals 40 ??) becomes larger.

Universal-battery-charger

Mon, 04 Jun 2012 00:06:00 MST

When power is applied to the circuit, SCRl is off, so there is no bias-current path to ground; thus, L~317 acts as a current regulator. The LM317 is umnected to the battery through steering diode Dl, limiting resistor Rl, and bias resistor R2. The steering diode prevents the battery from discharging through the LED and the SCR when power is removed from the circuit.

Lead-acid-battery-charger

Thu, 31 May 2012 00:05:00 MST

This circuit furnishes an initial voltage of 2.5 V per cell at 25Â° C to rapidly charge a battery. The charging current decreases as the battery charges, and when the current drops to 180 mA, the charging circuit reduces the output voltage to 2.35 V per cell, leaving the battery in a fully charged state. This lower voltage prevents the battery from overcharging, which would shorten its life. The LM301A compares the voltage drop across R1 with an18 mV reference set by R2. The comparator"s output controls the voltage regulator, forcing it to produce the lower float voltage when the batterycharging current, passing through R1, drops below 180 mA.

Current-Limited 6-V Charger

Fri, 11 May 2012 00:05:00 MST

An LM317HV regulator is used as a current-limited charger. If current through R4 exceeds 0.6 A, Ql is biased on

Low-battery-warning

Wed, 09 May 2012 00:05:00 MST

A voltage divider consisting of Rl, R2, and R3 is used to set the input reference voltage below which the batteries are to be replaced. That reference voltage, at point A, is varied by Rl. With the voltage divider shown in Fig. 9-7, a range of 2 to 3.5 Vis possible. When the battery voltage drops below that at point A, the output ol IC1a, 1/. of a LM339 quad comparator, switches from high to low. That triggers IC1b, which is configured as an astable multivibrator. Feedback resistors R6 and R7, coupled with capacitor Cl, determine the time constant of the multivibrator.

Ni-Cad battery charger

Mon, 30 Apr 2012 00:04:00 MST

The short in a Ni-Cad battery can be "burned off" with this zapper. Use of the SCR keeps heavy discharge current from damaging switch contacts.

NiCad Charger IV

Mon, 23 Apr 2012 00:04:00 MST

This zapper clears internal short in nickel cadmium batteries by burning it away. CAUTION: The negative battery terminal is connected to one side of the ac line.

Ni-cad discharge limiter

Wed, 18 Apr 2012 00:04:00 MST

The circuit disconnects the battery from the load when output voltage falls below a preset level. Cl charges through R1 and turns on Q2. Collector current flows through R2 turning Ql on and battery is connected to the load

Battery Charger

Wed, 11 Apr 2012 00:04:00 MST

This high-performance charger quickly charges gelled lead-acid batteries, and turns off at full charge. At first, the charg

Battery Charger Circuit

Fri, 06 Apr 2012 00:04:00 MST

The circuit is capable of supplying either a trickle (50 mA) or high-current (1-A) charge. You can select either charging method or an automatic mode that will first trickle charge a battery if it is particularly low before switching to high-current charging.If the battery`s voltage is low, Zener-diode D5 will not conduct sufficient current to produce a voltage drop across R6 to turn Q2 on. With Q2 off, R4 pulls the base of Ql high, turning it on. That activates Kl. With K1 active, the only thing between the battery and the power supply is R2 and D4 (which prevents current from flowing through the circuit from the battery).

Standalone NiMH/NiCd Battery Charger

Fri, 29 Mar 2013 00:03:00 MST

The LTC®4010 and LTC4011 are NiCd/NiMH battery chargers that simplify Nickel-based battery charger design and include power control and charge termination for fast charging up to 16 series-connected cells using a synchronous buck topology. The LTC4011 provides a full feature set in a 20-lead TSSOP while the LTC4010 comes in a 16-lead TSSOP.

Battery charger indicates rate of charge

Sun, 24 Mar 2013 00:03:00 MST

A single LED indicates whether the battery charger in Fig 1 is delivering a trickle charge or a fast charge. During fast charges, the LED stays lit continuously because IC2`s FASTCH output sinks dc. During trickle charges, the LED flashes because D1 and Q1 enable the 555 timer. The timer is an astable multivibrator operating at 60 Hz (f=1/1.4RC).

Charge Li-ion batteries from ac

Sat, 23 Mar 2013 00:03:00 MST

The circuit converts energy from 120V ac to a regulated voltage or current as necessary to charge two Li-ion cells in series. IC1, a popular controller for offline power-supply applications, operates as a forward converter, producing an isolated, half-wave-rectified battery voltage or current from the full-wave-rectified line voltage. This converter operates at 250 kHz and handles ac inputs from 90 to 135V.

Ideal Car Battery Charger

Sun, 17 Mar 2013 00:03:00 MST

The usual chargers of battery automotive, are simple and cheap appliances that charge continuously the battery, with a rythm of few amperes, for the time where the appliance is ON. If the holder do not close in time the charger, the battery will overcharge and her electrolytic faculty are lost with evaporation or likely exists destruction of her elements. The charger of circuit exceeds these faults. It checks electronic the situation of charge of battery and it has circuit of control with retroaction, that forces the battery charge with biggest rythm until charge completely. When charge completely, it turns on one RED led (LD2).

Capacitor Charger Lead Acid Battery

Sat, 23 Feb 2013 00:02:00 MST

Leaving aside the complex chargers, "stuffed" electronics capacitor charger is one of the best connections. Charging current is limited by the resistor (or other element of the changing excess energy into heat), but the reactance of the capacitor to the primary side. The charger is not heated, the greatest loss occurs only at the transformer and rectifier diode. Connecting the charger is in the picture 1 . On the primary side switch is transformátru P?1a, which we include in series with the primary winding of the transformer capacitors C1 to C3. Capacitors its reactance to limit current through the primary winding. B

Nickel Metal Hydride ( NiMH ) Charger

Fri, 15 Feb 2013 00:02:00 MST

This circuit will charge a 12v battery (10 NiMH cells) @ approx 220mA. It is a very simple circuit but requires correct setting up. The circuit is designed around a 12vDC, 500mA plug pack. This type of plug pack delivers about 17.5v to 18.5v DC on no-load and about 13v when the current is 500mA. Our circuit delivers 220mA to a set of AA cells and the output of the plug pack is approx 16v (when 220mA flows) and the voltage across a set of 10 NiMH AA cells is approx 13.5v during the charging process. This gives approx 4.5v for the "head voltage," and this creates the situation where the plug pack will deliver a current to the battery.

NiCd/NiMH Battery Charger

Fri, 08 Feb 2013 00:02:00 MST

Here we use the PIC16711. Rechargeable battery capacity is rated in mAH (milliampere-hours). The total capacity of a battery is defined as "C", that is it can supply C mA for 1 hour, or 2C for 30 minutes etc. Charge rates can vary from trickle charges to keep the battery 'topped up' of 3.3% of C to 5% of C, a slow current charge of 10% of C to 20% of C or a fast charge of 50% of C to 100% of C. Slow charges are not meant to be continually applied, and since NiCd/NiMH batteries are about 66% efficient, they normally last about 8-15 hours. Fast charges such as 100% of C should be terminated after about 1.5 hours, providing the battery is flat to begin with. Once a battery is fully charged, the battery produces gas creating a high internal pressure, and a sudden rise in temperature.

Motorcycle 13.6V 3A charger

Fri, 01 Feb 2013 00:02:00 MST

This 3A charger was originally designed to work with small batteries like those used in motorcycles. In principle it can be used to charge car batteries also but will take a lot longer.
The charger below charges a battery with a constant current to 14.1 volt. When this level is reached, the current charge drops automatically to a safer level (13.6V) and keeps charging at this slower rate untill the LED lights up indicating a fully charged battery. This project looks very much alike with the Gel cell II charger elsewhere posted in the 'Circuits' section. The difference is the IC, namely a LM1458 instead of a LM301A. Nice job Jan!

charge power drives battery

Thu, 31 Jan 2013 00:01:00 MST

A muscle-powered capacitor charger contains only a few components: a storage capacitor, a bridge rectifier, and a voltage-limiting zener diode that protects the capacitor from excessive voltages (Figure 1).

NiMH / Nicad Charger

Tue, 29 Jan 2013 00:01:00 MST

I Specifically Designed this circuit to charge 2 Batteries for my Digital Cameras, but it can be modified to charge 3, 4, 5 or more cell. However, It will Not Work with only One Cell as that voltage is too low for even this LDR Discharge Regulator. If you decide to Always charge 4 or more batteries, the REG1117A could be replaced with an LM317. But with only Two cell, this will not work. It is Recommended to set the discharge, Down to 1.1 volts per cell at a rate of 1/10 capacity. This Prevents any Memory from occuring. Therefore on an 1800 mAH battery, the Discharge current would be 180 mA. This is A SLOW PROCESS, And can take MANY HOURS, depending on the charge remaining in the battery.

Smart Battery Charging with COP8ACC

Mon, 28 Jan 2013 00:01:00 MST

Figure 1 shows a block diagram of the single slope, comparator based A/D converter. Using this approach an A/D converter can be configured by using only a single external capacitor. This capacitor provides the designer flexibility in controlling the resolution and conversion time.

Mobile Phone Charger with CA3130

Thu, 17 Jan 2013 00:01:00 MST

The circuit described here provides around 180mA current at 5.6V and protects the mobile phone from unexpected voltage fluctuations that develop on the mains line. So the charger can be left ?on? over night to replenish the battery charge. The circuit protects the mobile phone as well as the charger by immediately disconnecting the output when it senses a voltage surge or a short circuit in the battery pack or connector. It can be called a ?middle man? between the existing charger and the mobile phone. It has features like voltage and current regulation, over-current protection, and high- and low-voltage cut-off. An added speciality of the circuit is that it incorporates a short delay of ten seconds to switch on when mains resumes following a power failure.

Lithium Ion battery charging

Wed, 16 Jan 2013 00:01:00 MST

Portable hand-held applications such as cell phones, PDAs, etc are becoming increasingly complex with more and more features designed into every generation. This increasing number of features combined with a requirement for smaller size, extended battery life has made Lithium batteries the preferred choice for many of these applications.

Charge Limiter circuit

Tue, 15 Jan 2013 00:01:00 MST

Here is a deluxe version of the simple charge rate limiter, using the same idea but with the ability to charge two packs simultaneously from a single wall charger. For circuit description and parts list, see the simple charger page. Since wall chargers provide about 55 mA, you should not use this dual circuit to charge batteries at rates greater than 27 mA (for a total of 54 mA).

Nicad Battery Charger

Sun, 13 Jan 2013 00:01:00 MST

This simple charger uses a single transistor as a constant current source. The voltage across the pair of 1N4148 diodes biases the base of the BD140 medium power transistor. The base- emitter voltage of the transistor and the forward voltage drop across the diodes are relatively stable. The charging current is approximately 15mA or 45mA with the switch closed.

NiCads charger

Sun, 06 Jan 2013 00:01:00 MST

The driver circuit (see the complete schematic) has 4 main sections: * the voltage definition, * the integrator, * the current booster, and * the foldover. The schematic is drawn so that higher voltages are toward the top and lower voltages are towards the bottom. D1 is a voltage reference, LM385BZ-2.5 (you can get all these parts from Allied Electronics), that maintains a drop of 2.5 volts across its leads. Since B will be close to ground, there should be about 1.5 volts across R1 and about 0.8 mA of current, which is enough to keep D1 alive.

Li-Ion Linear Charger

Sun, 06 Jan 2013 00:01:00 MST

Linear battery chargers are typically smaller, simpler and less expensive than their switcher-based counter parts, but they have one major disadvantage: excessive power dissipation when the input voltage is high and the battery voltage is low (discharged battery).

Battery Charger

Fri, 04 Jan 2013 00:01:00 MST

This application note presents practical design considerations for battery chargers employing Green Mode FPS (Fairchild Power Switch). It includes designing the transformer and output filter, selecting the components and implementing constant current / constant voltage control.

Solar Charger circuit

Wed, 02 Jan 2013 00:01:00 MST

Few years back, I had been working on a project for solar auto lighting. The light will turn on when the the solar panel voltage drop below a set point indicating that it is dark. The detection is done by using D2 in the schematic. The zener diode value will be adjusted so that the transition between the switch depends on the amount of light the panel receive. Relay K1 is used to switch the load and the battery. If the battery power fall below a set threshold, the relay will cut the supply to the load. Relay K2 is used to control the charging of the circuit. When a Set point is reach the charging will be cut off. A Comparator is used for the voltage comparison.

Single Cell Lithium-ion battery charger

Wed, 02 Jan 2013 00:01:00 MST

The rechargeable Li-ion, I began to intensely interested last summer, when I managed to bring a holiday without a phone charger. After several experiments involving originated in Figure 1, which has proved. Involvement of the stage provides a limited current charging and constant voltage. Charging current from the rectified voltage of the transformer through the transistor T1, diode D5, resistor R2 and the battery back to AC power. Current flow creates a voltage drop on R2, which opens T2. The transistor T2 controls the current through T1 - the current is regulated so that R2 was approximately constant voltage drop. The collector is connected LED1 T2, indicating the stage of charging current.

Li-Ion Charge Termination IC

Sun, 23 Dec 2012 00:12:00 MST

Rechargeable lithium-ion batteries are rapidly becoming the battery of choice for many battery-powered products. These products include notebook computers, PDAs, video camcorders, digital cameras, cellular phones, portable test equipment and others. Compared to other rechargeable power sources, Li-Ion batteries have higher energy density for both weight and volume and provide longer run time between charges.

12V battery charger with 555

Sun, 23 Dec 2012 00:12:00 MST

The charger consists of two stages: The first is a capacitive voltage doubler, which uses a 555 timer IC driving a pair of transistors connected as emitter followers, which in turn drive the voltage doubler proper. The doubler has power resistors built in, which limit the charging current. The second stage is a voltage regulator, using a 7815 regulator IC. Its output is applied to the battery via a diode, which prevents reverse current and also lowers the voltage a bit. The resulting charge voltage is about 14.4V, which is fine for charging a gelled or AGM battery to full charge, but is too high as a trickle charger, so don't leave this charger permanently connected to a battery. If you would like to do just that, then add a second diode in series with D3!

NiCad charger with independent discharge

Fri, 14 Dec 2012 00:12:00 MST

If you use different batteries with actual capacity, with different self-discharge rate of batteries from different manufacturers, you will perhaps throw further described charger. Because each cell can be discharged separately recharge, can be charged with varying articles carrying charge. All of the described nabíjely NiCad battery chargers, or even be discharged all the articles (or group of cells) simultaneously. Such a charger is convenient to use if they are battery cells used in approximately the same capacity. It is met only with new and very long in storage batteries and battery assembled modellers, who can work with a collection of articles.

Stand-by Battery Charger

Thu, 13 Dec 2012 00:12:00 MST

This simple circuit will find many applications as a battery eliminator for low power requirements. It consists of a transformer, a bridge rectifier and an electrolytic capacitor followed by a zener controlled series pass transistor. The output is stabilized at +7.5V. The stand-by battery, 7.5V, in series with D7, floats across the output terminals, ready to take over in case of main failure. The voltage drop across D7 will then reduce the power supply to about 7V. The R3 has an additional function, when working off the mains it will trickle charge the dry cells or storage battery. It?s correct resistance can be found by dividing the voltage potential difference between the zener D6 and the battery by the safe trickle current, which may amount to some 0.7 milliamps.

12 VOLT GEL CELL CHARGER

Sun, 09 Dec 2012 00:12:00 MST

When a discharged gel cell is connected, the charger goes into a fast charge mode at a fixed rate of 400 ma. After the chip detects the voltage leveling off or when 4 1/2 hours has elapsed. (which ever happens first.) the fast charge will stop. After the fast charge has ended, the IC goes into a trickle charge rate of about 50 ma. This trickle charge continues until 13.8 volts is reached which will stop all charging current since the cell is now fully charged. If the cell voltage should drop for any reason, either a fast charge or trickle charge (IC will detect what is needed) will start again.

Built-in battery charger, Li-Ion

Sun, 09 Dec 2012 00:12:00 MST

Build-in charger for instruments powered by single lithium-ion or Li-Pol accumulator. If external power supply not conected to charger, current back from the accu charger is very small. New version improved temperature stability and Not Needed NTC thermistor. After a simple adjustment can be from initial engagement to launch a thermistor to compensate for temperature dependence. After adjustment (see Figure 1 ) operates as a transistor T4 not voltage follower, but as a switch. If charging voltage is present, transistor T4 is closed and the divider resistors R4 to R6 does not pass any current.

The Simplest Car Battery Charger

Fri, 07 Dec 2012 00:12:00 MST

This very simple circuit uses a transformer ,two diodes , a capacitor and an ammeter. To charge a battery just connect the + and - terminals of the circuit to the corresponding terminals of the battery. When the battery is not charged, the ammeter reading shows 1-3 amps. When the battery is fully charged the ammeter reads Zero or nearly zero, after which the battery should be removed from the charger.

Circuit Charges Lithium-Ion Cells

Sat, 01 Dec 2012 00:12:00 MST

The charger is built around a single LTC®1541, which contains a voltage reference, op amp and comparator. The high accuracy voltage reference (±0.4%) regulates the battery float voltage to ±1.2%, as required by most Lithium-Ion battery manufacturers.

Li-ion battery charger

Sun, 25 Nov 2012 00:11:00 MST

The circuit in Figure 1 can solve this problem by providing a constant 300-mV drop between VIN and VOUT at currents as high as 3A. The accuracy of the 300-mV drop is nearly as good as the accuracy of the input voltage, which in this case is approximately 1%. This circuit requires an input voltage that is fixed, regulated, and preferably current-limited.

Automatic Charger for Battery Hi-Fi Preamps

Sun, 25 Nov 2012 00:11:00 MST

This project is one for the experimenter, but as shown will work extremely well. The sensing circuit can be made so sensitive that a load of only 2.5mA is enough for the circuit to detect, and disconnect the charger. The idea is that the charger is left permanently connected, but of course that would normally introduce some hum into the supply lines.

Portable Ni-Cd Battery Charger

Sun, 25 Nov 2012 00:11:00 MST

The circuit shown in Figure 1 was designed to charge 12V, 2 ampere-hour Ni-Cd battery packs from a 12V source, but was made versatile enough to charge packs in the range of 4.8 to 15.6V to increase possible applications. To charge batteries that may reach a higher end voltage than the 12V supply input (even 12V Ni-Cd packs reach an end voltage of about 14.5V), a voltage converter of some kind is required.

Charger delivers 2.5A with 96% efficiency

Thu, 22 Nov 2012 00:11:00 MST

The circuit, which operates from a car battery, can charge a battery comprising one to six cells. IC1 is a buck-mode switching regulator that controls the external power switch, Q1, and the synchronous rectifier, Q2. These n-channel MOSFETs are more efficient than equivalent p-channel types, because the n-channel devices` on-resistance is lower, and they thus drop less voltage when conducting a given amount of current. IC1 includes a charge pump for generating the positive gate-drive voltage that Q1 requires.

Temperature Controlled NICD Charger

Sun, 18 Nov 2012 00:11:00 MST

This circuit is for a temperature controlled constant current battery charger. It works with NICD, NIMH, and other rechargeable cells. The circuit works on the principle that most rechargeable batteries show an increase in temperature when the cells becomes fully charged. Overcharging is one of the main causes of short cell life, hot cells pop their internal seals and vent out electrolyte. As cells dry out, they lose capacity.

Battery charger

Fri, 16 Nov 2012 00:11:00 MST

The NiCd and NiMH battery charger in Figure 1 applies a battery fast-charge controller IC in a way that not only provides peak-voltage fast-charge termination--as the IC was designed to do--but also precisely regulates the charge current. The design also features maximum-temperature backup shutdown. Efficiency exceeds 90% at a VIN of 14V.

Reasonable Car Battery Charger

Fri, 16 Nov 2012 00:11:00 MST

This charger will charge any 12V lead acid battery including flooded, gel and AGM. It is fully automatic and will charge at a rate up to about 4A until the battery voltage reaches a preset point at which it will switch to a very low current float charge. If the battery voltage drops again the charger will begin charging until the voltage once again reaches the cut off point. In this way it can be left connected to a battery indefinitely to maintain full charge without causing damage. An LED indicates when the battery is fully charged.

Lead Acid Battery Charger with LED indicator

Sat, 10 Nov 2012 00:11:00 MST

The above circuit is a precision voltage source, and contains a temperature sensor with a negative temperature co?ficient. Meaning, whenever the surrounding or battery temperature increases the voltage will automatically decrease. Temperature co?ficient for this circuit is -8mV per °Celcius. A normal transistor (Q1) is used as a temperature sensor. This Battery Charger is centered around the LM350 integrated, 3-amp, adjustable stabilizer IC. Output voltage can be adjusted with P1 between 13.5 and 14.5 volt. T2 was added to prevent battery discharge via R1 if no power present. P1 can adjust the output voltage between 13.5 and 14.5 volts. R4's value can be adjusted to accommodate a bit larger or smaller window.

Quick NiCd - NiMH Charger

Mon, 05 Nov 2012 00:11:00 MST

The charger is build around a LM317 (click to download datasheet) adjustable regulator. The charge starts when a battery is connected between pins JP1-JP4 or JP2-JP4 or JP3-JP4. For example, if a battery is connected to JP1-JP4 pins then the current that flows cause a voltage drop to R1, then D1 causes a voltage drop of 0,7 volts and ?1 conducts. Then through transistor's emitter flows a current that comes from Adjustment pin of LM317. Diode D4 prevents current to flow from battery back to the charging circuit. Resistors R1,R2 and R3 adjusts the charging current and it's value is given from : Rx=(1,25 + 0,1) / I , where x = 1,2,3.

Lead-Acid Battery Charger

Mon, 05 Nov 2012 00:11:00 MST

The circuit is actually a half-wave rectifier. It only charges the battery on every half cycle. The plug pack doesn't like this as it leaves residual flux in the core of the transformer and causes it to overheat. But that's the only drawback with the circuit. The SCR turns on during each half cycle and current flows into the battery. A voltage is developed across the two 1R8 resistors (in parallel) and this voltage is fed into the 47u electrolytic. It charges and turns on the BC547 transistor. The transistor robs the SCR of gate voltage and the SCR turns off. The energy in the 47u feeds into the transistor but after a short time it cannot keep the transistor turned on.

Li-Ion Charge Termination Using the LT1505

Sat, 03 Nov 2012 00:11:00 MST

Li-Ion batteries are normally charged with a current limited constant voltage for a fixed length of time. At the end of this time period, the voltage must be removed to prevent internal chemistry changes in the battery. At a minimum, a timer is needed to terminate the charging process after the maximum amount of time required to fully charge the battery.

Nicad / NiMh Battery charger

Sat, 27 Oct 2012 00:10:00 MST

Using this circuit will give Good Charging results to a Sealed Lead Acid Battery, like I use in the Metal Detector. This Circuit is Extremely Small in size and has a low parts count, making it ideal in some situations. It can also be adapted for Charging Nicads. This charger is both Current and Voltage Regulated and the Output is short circuit protected. The 1 Ohm resistor is a Fusing Resistor, Protecting the battery in case a short occurs. With the 2.2 ufd capacitor it will produce an output of about 100 Ma. A capacitor of 1 ufd will produce an output of about 50 Ma. The Zener used here, is rated at: 14 Volt and 5 Watts.

high-frequency battery-charger

Sun, 21 Oct 2012 00:10:00 MST

The waveforms in Figure 1 illustrate good and bad power-factor conditions. Trace A, at the top of the figure, is the voltage common to the current waveforms below. Trace B is an ideal current, in phase, with a 1.0 power factor and delivering peak current of 7.07A.

Dual Smart Battery Charger

Tue, 16 Oct 2012 00:10:00 MST

Figure 1 shows a typical dual battery charger. This circuit can charge batteries with up to 4A and switch continuously down to zero load currents. This circuit takes advantage of ceramic capacitors space saving features without producing any audible noise. The high 300kHz switching frequency allows the use of small low cost 10µH inductors.

Lead Acid Battery Charger III

Thu, 11 Oct 2012 00:10:00 MST

This high-performance circuit first quickly starts (and holds) the charge at 2 amp, but as the voltage rises the current will consequently decrease. When the current falls below 150mA, the charger automatically switches to a lower 'Float' voltage to prevent overcharging. At the point that a full charge is reached, Q1 will bias and the LED will light. The LM301A is a 8-pin OpAmp. Transistor Q1 is a PNP, Silicon, AF-Out type with a TO-39 metal case and can be substituted for a NTE or ECG129. Diode D1, a Si, GP Det. type, can be substituted with a NTE177 or ECG177. The LM350 (U1) needs to be cooled. The input voltage should equal or about 18volts.

Charger serves load while charging battery

Fri, 05 Oct 2012 00:10:00 MST

The battery-charger circuit in Figure 1 monitors the battery voltage and automatically initiates a recharge if required. Its output-current capacity is sufficient to simultaneously charge the battery and supply the load. It thus provides continuous power to the load during recharge operations. The circuitry in IC2 provides "smart" charge terminations for either NiCd or NiMH batteries.

Chargers Use LM2576

Fri, 05 Oct 2012 00:10:00 MST

This design is a 3A battery charger intended for use with 5-cell Ni-Cd or Ni-MH battery packs (but can be modified to suit other numbers of cells). The circuit includes automatic shutoff that occurs when the battery temperature rises 10°C above ambient.

Power inverter bidirectional

Thu, 04 Oct 2012 00:10:00 MST

The circuit can generate a negative output from a positive supply or a positive output from a negative supply. When the circuit starts up, the substrate diode of the output FET bootstraps the output voltage to the point where synchronous switching takes over.

Car Battery Charger

Fri, 28 Sep 2012 00:09:00 MST

This Charger Can't be used as a Power Supply, Without having a battery in place. The Battery MUST be Connected to get power out. Note: This Charger Features a Reverse polarity Indicator. Instructions: Before plugging this charger into the 110 volt line (or turning it on if you use a Switch), FIRST Connect this Charger to the Battery. In doing so, No Damage will occur if the battery is accidently connected in reverse, but the Reverse Polarity LED will light up. If that LED Does light, Reconnect the battery Correctly, than apply the 110 line voltage. Connecting the Line voltage, With a reversed battery connection, WILL Result in Damage. Especially if you don't use the fuse on the output, as shown in the schematic. Although Not Shown in the schematic, A suitable Line fuse would also be advisable.

New Charger Maximizes Charging Speed

Tue, 25 Sep 2012 00:09:00 MST

The block diagram in Figure 1 shows the basic functions performed by a battery charger IC using this patented topology*. The LT1511 is a high efficiency 200kHz switching regulator IC in a step-down configuration suitable for charging lithium-ion batteries. It contains multiple feedback loops for constant charge voltage, constant charge current and input current limit.

Lead Acid Battery Charger with voltmeter

Mon, 24 Sep 2012 00:09:00 MST

This simple circuit makes it posible to monitor the charging process to a higher level. If you need more information then check out the LM3914 Datasheet. Final adjustsments are simple and the only thing needed is a digital voltmeter for the necessary accuracy. Connect an input voltage of 12.65 volt between the positive and negative poles and adjust the 10K trimmer potentiometer until Led 10 lights up. Lower the voltage and in sequence all other Led's will light up. Check that Led 1 lights up at approximately 11.89 volts.

Step-up supply charges battery

Sun, 23 Sep 2012 00:09:00 MST

The circuit in Fig 1 supports portable applications in which a microprocessor controls battery charging. Step-up switching regulator IC1 boosts VIN (5V) to supply a combination of charging and load current. (Note that the 5V source must have short-circuit protection.) IC2 is a high-side current-sense amplifier that monitors charging current. Commands from the processor are CHARGE ON /OFF and FAST/TRICKLE CHARGE.

A Solar Cell Battery Charger

Sat, 15 Sep 2012 00:09:00 MST

This Circuit will allow for Voltage Regulation and Isolation when Charging Lead Acid Batteries with a Solar Cell.

12 Volt 20 Amp Solar Charger

Thu, 13 Sep 2012 00:09:00 MST

The SCC3 is a solar charge controller, it`s function is to regulate the power flowing from a photovoltaic panel into a rechargeable battery. It features easy setup with one potentiometer for the float voltage adjustment, an equalize function for periodic overcharging, and automatic temperature compensation for better battery charging over a wide range of temperatures. The SCC3 rev C design is able to handle reverse polarity connection of both the battery and photovoltaic panel.

MOBILE CELLPHONE CHARGER

Thu, 13 Sep 2012 00:09:00 MST

Charging of the cellphone battery is a big problem while travelling as power supply source is not generally accessible. If you keep your cellphone switched on continuously, its battery will go flat within five to six hours, making the cellphone useless. A fully charged battery becomes necessary especially when your distance from the nearest relay station increases. Heres a simple charger that replenishes the cellphone battery within two to three hours.

Fast charging batteries with Zetex

Tue, 11 Sep 2012 00:09:00 MST

The advances of digital technology and a waiting market have created a huge demand for portable products including cellular telephones, PDAs, laptop computers, CD players, and gaming systems. By their nature, all of these products must derive their energy from an integral rechargeable cell/battery pack that must periodically be re-charged from a mains outlet.

Smart Battery Charger

Sun, 02 Sep 2012 00:09:00 MST

Typically such applications require low power from the battery. With this in mind, every feature of the LTC4100 Smart Battery charger exists to reduce board real estate and profile requirements. The LTC4100 is a Level 2 (slave) Smart Battery charger that is compliant with both Smart Battery Charger V1.1 and SMBus V1.1 standards.

CHARGER WITH ANALYSER

Fri, 31 Aug 2012 00:08:00 MST

Nowadays maintenance-free lead-acid batteries are common in vehicles, inverters, and UPS systems. If the battery is left in a poor state of charge, its useful life is shortened. It also reduces the capacity and rechargeability of the battery. For older types of batteries, a hygrometer can be used to check the specific gravity of the acid, which, in turn, indicates the charge condition of the battery.

AA Battery Solar Charger

Mon, 20 Aug 2012 00:08:00 MST

This almost trivial circuit may be used to charge a pair of AA or AAA sized rechargeable battery cells from sunlight. The circuit has been used to keep a Palm Pilot and walkman radio running perpetually. This is an unregulated charger, proper charging is achieved by placing the unit in the sun for a known amount of time, this time varies according to the battery type.

Solar charger for lead-acid batteries

Fri, 17 Aug 2012 00:08:00 MST

This circuit 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.

Ni-Cd Battery Automatic Charger

Thu, 16 Aug 2012 00:08:00 MST

The circuit presented in the above schematic has been designed to charge automatically two series 350mAh "AAA" size batteries. Set the 20KOhms multiturn potentiometer to get a 2.78V on the 3rd pin of the LM311 which is a comparator. So if the net voltage of batteries reaches at 2.81V, the output of the LM311 goes high and then the state of the transistor becomes off, resulting in charging operation stops. When the red LED is lighted, it indicates that the charging is in the progress, and vice versa.

Microcontroller controls battery charger

Thu, 16 Aug 2012 00:08:00 MST

Figure 1 is a generalized block diagram of a multichemistry battery charger. A COP8ACC5 µC handles its key charging features. The µC is available in a 20-pin (15 I/O pins) SOIC or a 28-pin (23 I/O pins) SOIC/DIP. It contains 4 kbits of internal ROM.

PIC16F84 Solar Charger

Sun, 05 Aug 2012 00:08:00 MST

The previous version of this device used pulse width modulation (pwm) to control the power from the five solar panels to charge the battery bank. Under full sun conditions the MOSFETS got a bit warm and the whole unit radiated a lot of RFI. This design uses a set of relays - one for each panel. If the controller decides the battery voltage is too low, it engages another relay; if its too high, it drops one out. This tends to 'float' the voltage at about 14 volts as long as sufficient sunlight is available.

Battery Charger

Thu, 02 Aug 2012 00:08:00 MST

Using this circuit will give Good Charging results to the Gell Cell Battery used in the Metal Detector, or any other simular and smaller type battery. This charger is both Current and Voltage Regulated.

Buck-converter charger

Thu, 26 Jul 2012 00:07:00 MST

The design in Figure 1 uses two simple-switcher buck converters. The first regulator, IC1, efficiently steps down the unregulated input voltage from the rectifier`s output. This buck converter generates the input voltage for the battery and provides voltage to the second regulator. The second regulator, IC2, is a small DIP or SOIC capable of providing as much as 0.5A of system VCC. You must consider the system-current requirements when setting the charger`s current-limit value. You must increase the current-limit value (set by the gain of IC2) by the amount of current necessary to supply system power.

Lithium-lon Battery Charger

Wed, 25 Jul 2012 00:07:00 MST

FAN7563 (FAN7564) was carefully designed to achieve the required characteristics as follows. FAN7563 has basically three functions, which are voltage sensing for constant voltage, peak charging(load) current sensing for constant current and a charging current monitoring function for the charging state.

Lead-acid charger

Tue, 24 Jul 2012 00:07:00 MST

This charger design comprises a 12V, 0.5A wall transformer and an LM2941CT voltage regulator, IC2. The wall transformer provides the unregulated dc voltage to IC2, which the circuit uses to charge the battery and hold its voltage at 13.8V. R3, R4, and D3 through D12 set the regulator output voltage. You should adjust R4 for an output voltage of 13.8V with the battery disconnected.

Charger for 12V lead acid battery

Mon, 16 Jul 2012 00:07:00 MST

A battery is a vital element of any battery-backed system. In many cases the battery is more expensive than the system it is backing up. Hence we need to adopt all practical measures to conserve battery life. As per manufacturer's data sheets, a 12V rechargeable lead-acid battery should be operated within 10. IV and 13.8V. When the battery charges higher than 13.8V it is said to be overcharged, and when it discharges below 10.IV it can be deeply discharged. A single event of overcharge or deep discharge can bring down the charge-holding capacity of a battery by 15 to 20 per cent. It is therefore necessary for all concerned to monitor the charge level of their batteries continuously.

Broken Charger-connection Alert

Sat, 14 Jul 2012 00:07:00 MST

The above circuit can be useful to detect if the load of any battery charger or plug-in adaptor supply is not properly connected. The load can be a set of batteries to be charged or any other type of battery or low dc voltage operated device.

Sealed Lead-Acid Charger

Sat, 14 Jul 2012 00:07:00 MST

Here`s how to make a good charger for a sealed lead-acid battery (this will NOT work with NiCad batteries) that`s faster (because it allows more current into the battery initially) and safer (because it uses lower voltage when the charging is finished). The battery can be left plugged into this charger indefinitely, and it won`t bother it in the slightest. In fact this is the "float" or "standby" charging method recommended by battery manufacturers.

Battery Charging Systems

Tue, 10 Jul 2012 00:07:00 MST

With the introduction of the LM317, a 3-terminal adjustable regulator, it becomes relatively easy to design high-performance, low-cost battery charging systems. Even single battery cells can be charged on this new regulator, which is adjustable down to 1.2V. The internal protection circuitry can be used to limit charging current as well as to protect against overloads. The output voltage is easily adjusted so multiple voltage chargers can be made.

LM3647 Reference Design

Tue, 10 Jul 2012 00:07:00 MST

The LM3647 provides a single-chip charge management solution for Nickel Cadmium, Nickel Metal Hydride and Lithium-Ion cells. The device handles the entire charging process from rejuvenating deeply discharged cells to providing a number of charge termination and maintenance options. The LM3647 Demo Board allows users to create a battery charging solution with little effort.

Charge Monitor for 12V lead acid battery

Tue, 03 Jul 2012 00:07:00 MST

As per manufacturer`s data sheets, a 12V rechargeable lead-acid battery should be operated within 10. IV and 13.8V. When the battery charges higher than 13.8V it is said to be overcharged, and when it discharges below 10.IV it can be deeply discharged. A single event of overcharge or deep discharge can bring down the charge-holding capacity of a battery by 15 to 20 per cent. It is therefore necessary for all concerned to monitor the charge level of their batteries continuously.

9 V NiCd or NiMH accumulator charger

Tue, 03 Jul 2012 00:07:00 MST

Most universal chargers to charge the battery 9 V (8.4 V more). However, while the charging of NiCd or NiMH rechargeable governed by a special circuit or a microprocessor, 9 V batteries are recharged mostly from current sources. I use several of these batteries in measuring instruments, and several have already happened to me, that I forgot the battery and it nabíjel few days. Described charger charges while also just a constant current charging but after about 14 hours ends.

FAST CHARGER controlled by a 68HC11

Fri, 29 Jun 2012 00:06:00 MST

Note first the battery to be treated at the center of the figure. It is connected to contacts of a relay. The diagram shows the relay at rest. Under these conditions the battery is in SHOCK . His pole - is grounded and its positive pole to the circuit of constant current discharge. This circuit consists of N-channel MOSFET controlled by the TM2 IC2B OP amp. The input of this amp + e is at a potential adjustable by the digital potentiometer IC 4. The op amp will therefore act on the conduction of TM2 to pass in R17 to cause sufficient current to equal voltages and e + e-. It is understandable that by adjusting the voltage by e + IC4 is going to vary the intensity of discharge. The adjustable P4 allows the setting of the value of the intensity at the focus.

Automatic Charger with CD4541

Sat, 23 Jun 2012 00:06:00 MST

fixed Current Battery Charger

Tue, 19 Jun 2012 00:06:00 MST

A simple method of charging a battery from a higher voltage battery is shown in the circuit below to the left. Only one resistor is needed to set the desired charging current and is calculated by dividing the difference in battery voltages by the charge current. So, for example if 4 high capacity (4000 mA hour) ni-cads are to be charged at 300 mA from a 12 volt battery, the resistor needed would be 12-(4*1.25)/0.3 = 23.3 ohms, or 22 ohms which is the nearest standard value. The power rating for the resistor is figured from the square of the current times the resistance or (0.3)^2 * 22 = 2 watts which is a standard value but close to the limit, so a 5 watt or greater value is recommended.

RC Charger

Wed, 13 Jun 2012 00:06:00 MST

Charge current: I=0,45V/R2 Power-dissipation by R2: (0,45 * 0,45 / R2) ! Please adjust 13,8V by R5 without connected battery.

Li-ion Battery Charger

Fri, 08 Jun 2012 00:06:00 MST

The features of the MC68HC908QY/QT include a 4-channel Analog to Digital Converter and Timer module which can be set to generate PWM signals. This feature makes this MCU suitable for application such as a single cell Li-ion battery charger. The MC68HC908QY/QT is available in several packages with different memory size to fit into various applications.

Simple Lead Acid Battery Charger

Thu, 07 Jun 2012 00:06:00 MST

The above pictured schematic diagram is just a standard constant current model with a added current limiter, consisting of Q1, R1, and R4. The moment too much current is flowing biases Q1 and drops the output voltage. The output voltage is: 1.2 x (P1+R2+R3)/R3 volt. Current limiting kicks in when the current is about 0.6/R1 amp. For a 6-volt battery which requires fast-charging, the charge voltage is 3 x 2.45 = 7.35 V. (3 cells at 2.45v per cell). So the total value for R2 + P1 is then about 585 ohm. For a 12 V battery the value for R2 + P1 is then about 1290 ohm.

Car-Battery charger for Nokia 8210

Wed, 06 Jun 2012 00:06:00 MST

It`s just a simple power supply with a 7805 regulator, the chip must be mounted on a large metal radiator, because the current requested by the regulator is near 0.4 A

Nicad/NiMH Charger

Fri, 01 Jun 2012 00:06:00 MST

This device is built around a PIC12F675 (a dandy little part from Microchip). The number of cells (1 to 8) is programmed in using the one button. The cell count is saved in EEPROM the next time you power up the device. Using just one button for all operations is a bit tricky, but easy once you try it a few times. There are 2 types of button operations: Hit (less than 1 second), and Hold (over 1 second). Here is what to do. Apply power (12 to 24 volts DC) to the jack. Then, connect the batteries.

Li-ion boost circuit uses no inductors

Fri, 18 May 2012 00:05:00 MST

The circuit in Figure 1 senses the battery voltage via the R1-R2 resistor divider at comparator IC2. The comparator turns off the converter when the battery voltage exceeds 3.6V. The regulator alone suffices in the battery range of 4.2 to 3.5V, but below that level, the battery voltage needs boosting to keep the LDO IC in regulation.

Emergency Light with Charger

Sun, 13 May 2012 00:05:00 MST

The circuit shown here is that of the IC controlled emergency light. Its main features are: automatic switching-on of the light on mains failure and battery charger with overcharge protection.

Battery charger and PSU

Thu, 10 May 2012 00:05:00 MST

This circuit was created for digital cameras. It's known the digital cameras have considerable power consumption. For example my camera Minolta E223 requires approximately 800 mA. In practice a mains power supply or high capacity NiMH accumulators (batteries) can satisfy this demand. This circuit consists of two parts, charger and adapter. The transformer, rectifier bridge and buffer condensator are common. Adapter is quite simply its main part is an adjustable voltage regulator LM 317 according to usual setting. Output is a suitable for camera jack plug. Voltage can be adjusted in range 2-9 V.

Lead Acid Battery Charger II

Wed, 09 May 2012 00:05:00 MST

The above pictured schematic diagram is just a standard constant current model with a added current limiter, consisting of Q1, R1, and R4. The moment too much current is flowing biases Q1 and drops the output voltage. The output voltage is: 1.2 x (P1+R2+R3)/R3 volt. Current limiting kicks in when the current is about 0.6/R1 amp.
For a 6-volt battery which requires fast-charging, the charge voltage is 3 x 2.45 = 7.35 V. (3 cells at 2.45v per cell). So the total value for R2 + P1 is then about 585 ohm. For a 12 V battery the value for R2 + P1 is then about 1290 ohm.

Switching current pump charger

Tue, 08 May 2012 00:05:00 MST

The alternative design in Figure 1, which is based on a switching-inductive current pump, is much simpler and easier to build because it uses common discrete devices. Also, the primary design goal of a switching voltage regulator is to keep the constant output voltage under the different load conditions, but a current pump is designed to maintain constant load current under varying terminal voltages.

Lead Acid Battery Discharge protector

Tue, 08 May 2012 00:05:00 MST

In perfect discharge the batteries of lead acid, exists the fear they are destroyed. This circuit makes the work, this detection of discharge, protecting the batteries from destruction. At the discharge the polar voltage of batteries 12V of Lead acid, is not allowed it is decreased under 10.8V, thus we have warning with the turn on of Led, when the voltage falls under this price. In order to we achieve the control, we needed a stability voltage and a circuit that could him compare with the checked voltage. And two these condition provide to IC1- LM 723.

ALKALINE CHARGER

Mon, 07 May 2012 00:05:00 MST

This circuit was specifically designed to recharge alkaline cells. The unusual connection of the transistor in each charging unit will cause it to oscillate, on and off, thus transferring the charge accumulated in the capacitor to the cell. The orange LED will blink for around 5 times a second for a 1.37V cell. For a totally discharged cell the blinking is faster but it will decrease until it will come to a stop when the cell is charged. You may leave the cell in the charger as it will trickle charge and keep it at around 1.6V.

LM3647 Reference Design

Mon, 07 May 2012 00:05:00 MST

Car Battery Charger

Wed, 02 May 2012 00:05:00 MST

This charger will quickly and easily charge most any lead acid battery. The charger delivers full current until the current drawn by the battery falls to 150 mA. At this time, a lower voltage is applied to finish off and keep from over charging. When the battery is fully charged, the circuit switches off and lights a LED, telling you that the cycle has finished.

Switching regulator charges NiMH batteries

Sun, 29 Apr 2012 00:04:00 MST

In Figure 1, an MC34063A switching regulator and an MC33342 NiMH battery-charger IC combine to generate from an unregulated power supply a 600-mA battery charger for one to four NiMH cells.

Simple Li-Ion Battery Charger

Thu, 26 Apr 2012 00:04:00 MST

Charging current is about 100+mA, which is the internally-limited maximum current of the LP2951. For those wondering, this is compatible with just about any single-cell li-ion battery since li-ion can generally accept a charging current of up to about 1c (i.e. charging current in mA equivalent to their capacity in mAh, so a 1100mAh li-ion cell can be charged at up to 1100mA and so on). A lower charging current just brings about a correspondingly longer charge time. IMHO 100mA is quite low, low enough that the circuit can be used for an overnight charger for many typical single-cell li-ion batteries.

Charge indicator gauges lead-acid batteries

Wed, 25 Apr 2012 00:04:00 MST

A simple circuit measures the open-circuit voltage, such as the expanded-scale voltmeter circuit in Figure 2, which follows the curve in Figure 1. Sealed lead-acid batteries are available in several sizes, from a single D size (2.5 Ahr) to multicell rectangular battery packs.

High Efficiency Lithium-Ion Battery Charger

Wed, 25 Apr 2012 00:04:00 MST

The LT®1510 current mode PWM battery charger is the simplest, most efficient solution for fast charging modern rechargeable batteries including lithium-ion (Li-Ion), nickelmetal- hydride (NiMH) and nickel-cadmium (NiCd) that require constant current and/or constant voltage charging. The internal switch is capable of delivering 1.5A DC current (2A peak current).

Battery Charger & DC/DC Converter

Sun, 22 Apr 2012 00:04:00 MST

The LTC1980 manages both battery charging and generaton of the regulated system bus voltage via a unique bidirectional pulse-width modulator design (Figure 3). When the wall adapter is present, power passes directly to the system load DC/DC converters and to a pulse widthmodulated battery charger formed by M1, M2, T1 and the LTC1980.

3.6 Volt Lithium Ion Battery Charger (PIC12F675)

Sat, 21 Apr 2012 00:04:00 MST

Lithium Ion batteries pack a lot of power by weight compared to other types. There are 2 things that need to be handled differently than nicad on NiMH. They cannot be used as a direct substitute (even if they look like other AA's) since they run at about 3.6 (or so) volts. They cannot be charged in the same way as nicad or NiMH.

3.3V lithium-cell supply requires one inductor

Mon, 16 Apr 2012 00:04:00 MST

This converter also requires either a transformer or two inductors in place of the single inductor that most dc/dc converters require. You might overlook an alternative approach because the converter uses a linear regulator and takes an efficiency hit when you fully charge the Li-ion battery to about 4.2V (Figure 1).

1A Shunt battery charger

Mon, 16 Apr 2012 00:04:00 MST

The heart of the circuit is IC1, an LT1635, which contains an op amp and a reference. Operation is straightforward. A feedback divider comprising two 1-Mega-ohm resistors senses the battery voltage. The circuit amplifies the internal 200-mV reference to 7.05V and compares this voltage with the feedback signal.

Car Battery Charger

Sat, 14 Apr 2012 00:04:00 MST

Portable Solar Charger

Sat, 14 Apr 2012 00:04:00 MST

The circuitry for charging batteries is unregulated, and depends on the operator to disconnect the battery before it gets overcharged. The circuitry for the NiCads is an especially crude regulator, but it keeps the batteries from over-charging. Here, two series silicon rectifiers limit the voltage to about 1.3- 1.4 Volts (1.43 Volts is about ideal for a NiCad to terminate charge), A planned improvement is to add real regulators so that over-charging cannot occur. A 14 Volt fixed-voltage-regulator would be ideal for the lead-acid battery, and maybe something a little more sophisticated for the NiCads.

4-Cell Ni-Cad Regulator/Charger

Thu, 12 Apr 2012 00:04:00 MST

The new LTC1155 Dual Power MOSFET Driver delivers 12V of gate drive to two N-channel power MOSFETs when powered from a 5V supply with no external components required. This ability, coupled with its micropower current demands and protection features, makes it an excellent choice for high side switching applications which previously required more expensive P-channel MOSFETs.

NiCd Battery Fast Charger

Tue, 10 Apr 2012 00:04:00 MST

This is an advanced battery charger design based on Maxim`s battery charger IC MAX712. This device can, using a minimal set of external components, fast-charge an NiCd/NiMH rechargeable battery. Fast charge is terminated using several detection methods, including dV/dt, dT/dt and a time-based cutout. Full details can be obtained from the MAX712 datasheet, available at the Maxim Inc.

MOBILE PHONE BATTERY CHARGER

Sat, 07 Apr 2012 00:04:00 MST

Mobile phone chargers available in the market are quite expensive. The circuit presented here comes as a low-cost alternative to charge mobile telephones/battery packs with a rating of 7.2 volts, such as Nokia 6110/6150.

Shunt Regulator for Solar Cells

Thu, 05 Apr 2012 00:04:00 MST

One application is where you need a Higher Power Zener, Possibly even a 100 watt rating. Another useful application is as a Shunt Regulator for Solar Cells that are used to charge "Lead Acid Batteries". Simply Place it in parallel with the Solar Cell and use Diode De-coupling between it and the battery.

Charge Monitor for 12V Lead-acid Battery

Wed, 04 Apr 2012 00:04:00 MST

The circuit possesses two vital features: First, it reduces the requirement of human attention by about 85 per cent. Second, it is a highly accurate and sophisticated method. Input from the battery under test is applied to LM3914 IC. This applied voltage is ranked anywhere between 0 and 10, depending upon its magnitude.

Bringing NiCd`s from the dead

Sun, 01 Apr 2012 00:04:00 MST

The failures the article talks about occur in mutli-cell Ni-Cd battery packs, and are due to the voltage differences between cells. Say you have four 1.25 V cells in a pack connected to a 200 ohm load. The load "sees" 5 volts and draws 25 mA. Since each cell must pass the entire 25 mA and each cell`s potential is 1.25 volts, Ohm`s Law tells us that each cell sees the equivalent load of 50 ohms.