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fixed Current Battery Charger
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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.
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9 V NiCd or NiMH accumulator charger
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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...
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NiCad charger with independent discharge
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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. ..
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Single Cell Lithium-ion battery charger
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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. ..
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| Clicks: 7456 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Built-in battery charger, Li-Ion
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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. ..
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Capacitor Charger Lead Acid Battery
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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..
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NiCd/NiMH Battery Charger
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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. ..
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Crossed from: Various Circuits | Clicks: 17556 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
Reasonable Car Battery Charger
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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...
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12V battery charger with 555
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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!..
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Charge Limiter circuit
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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)...
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Crossed from: Various Circuits | Clicks: 10305 | Votes: 0 | Comments: 0 | Rating: 0 | Rank: 0
The Simplest Car Battery Charger
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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. ..
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Charger for 12V lead acid battery
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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. ..
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Nickel Metal Hydride ( NiMH ) Charger
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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. ..
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Lead-Acid Battery Charger
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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. ..
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Lead Acid Battery Charger III
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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...
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