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Simple Battery Low Voltage Beeper circuit provides an audible and visual low voltage warning for 12V battery powered devices. When the battery voltage is above the set point (typically 11V), the circuit is idle. If the battery voltage should fall below the set point, the LED will light and the speaker will emit a periodic beeping sound to warn of the impending loss of power. The circuit was designed for monitoring solar systems, but it could also be useful for automotive and other 12V applications. Specifications: Nominal operating voltage: 12V Idle current: 6ma Low Voltage Warning current: 15ma Theory: U2 provides a 5V regulated voltage reference. U1 is wired as a comparator, it compares the fixed 5V regulated voltage to the voltage on the wiper of VR1, that is proportional to the 12V supply. When the supply drops below the set point, the output of U1 goes low, turning on Q1 and powering the beeper and the LED. The beeper consists of U4, a tone generator, and U3, a low duty cycle pu...

I’ve owned a Iphone for a while now, it’s an amazing phone, the best I have ever used so far. But when I first started using it, my only concern was that the battery didn’t last as much as I expected. After two days, it was gone, and when I needed it, the phone just didn’t turn ON. I used to let the wireless on almost all the time and downloading many new apps. Now that I have some more experience on how my little gadget works, I will try to share some ideas on how you can optimize your iphone’s battery life and have a better iExperience. Wireless connectivity will drawn your battery even if you are not using it. Keeping it on, it will always try to connect to some open hot spot, try to check your emails and much more. So a good idea is to turn it on when using, and after, turn it off. Bluetooth have a similar battery usage as Wi-Fi, so there’s not much reason to leave it on if you are not using it (I believe that the most common usage for bluetooth today is the headsets and car kits)....

Ultra Fast Battery Chager for Nickel-Cadmium battery cells [NiCad] which will be discussed in this article is Fast NiCad Battery Charger, called the Ultra Fast Charger Battery Charger NiCad because it can make filling fast NiCad Batteries Cell. A battery charger in Desai has a fast charging capabilities such as Ultra Fast Battery Chager for Nickel-Cadmium battery cells [NiCad] on this article shall be equipped with some ability to protect the battery and charger circuit itself. Feature owned by Ultra Fast Battery Chager for Nickel-Cadmium battery cells [NiCad]  Autoshut-off, is the ability of the charger to stop charging current to a NiCad battery if the capacity NiCad battery is fully charged. Polarity Protection, with the existence of this capability so if there are mounting the battery on the charger upside yan can be known. Constant output voltage Output currents enough to fill some NiCad batteries at once in parallel. Short Circuit Protection, with the existence of this protec...

Battery-life measurement for a portable system is a time-consuming task and many methods used for it do not give reliable results. Presented here is a circuit using which you can measure the battery-life very easily. Here, an analogue clock tracks the discharge time of the battery used in battery-powered portable devices. Circuit and working The circuit for battery-discharge measurement is shown in Fig. 1. It is built using low-power single-/dual-supply comparator MAX921 (IC1), MOSFET VN0300L (IRF1), an analogue clock and a few other components. IC1 monitors the life of the BUT (battery under test) and controls the power supply for the analogue clock. When the BUT voltage falls below the threshold value set by VR1, IC1’s output becomes low, which turns off MOSFET IRF1. This means, power supply for the analogue clock is cut off and so the clock stops running. The reading on the clock at this point gives the discharge time of the BUT, provided you had set the clock to 12:00 before testin...

A simple battery charger that disconnects the battery when charge voltage reaches its nominal voltage and reconnects when battery voltage falls below a predefined level, can be designed using this circuit diagram. Circuit diagram : Autoconnect Disconnect Battery Charger Circuit diagram A fraction of the battery voltage is taken from the voltage divider R1-R2-R3-R4 and compare with a reference voltage with the help of IC2b. As long as the battery voltage is 0 V. The input current of AO produces a small voltage drop on R5, so IC2c pass in "0". Therefore, the relay remains disengaged. When connecting a battery, low residual voltage provide switch of IC2c, diodes D4 and D5 are reverse biased, a voltage reference applied to the noninverting input of IC2d and relay is activated. In these conditions, the battery charge until its voltage reaches the nominal level. Calibration is performed with a voltmeter connected to the output of IC2a, then P2 is adjusted, to obtain an indi...

The circuit below illuminates an LED to indicate unequal charges between two 12 volt lead batteries. It can be used to verify that two batteries are connected in parallel or isolated since the LED will be off when the voltages are equal within a tollerance, or on if the voltage difference is greater than 100 millivolts. Three comparators and three voltage dividers are used to determine battery conditions. Battery Equal Charge Indicator Circuit Diagram The upper left comparator (+) input at pin 5 is set to about 10 volts with battery #1 at 12 volts. The negative input (pin 4) is set to a slightly lower voltage by adding an additional 240 ohms to the voltage divider so that the output of the comparator will be positive when both battery voltages are equal and negative if battery 2 rises above battery 1 by 100 millivolts or more. The voltage at pin 5 is used as a reference for the lower comparator and the negative input of the lower comparator is set to a lower voltage with the addition o...

Build a 12V 7.2Ah SMF Battery Charger Circuit Diagram . The LM317 is an adjustable three-terminal positive-voltage regulator capable of supplying more than 1.5A over an output-voltage range of 1.25 V to 37 V. It is exceptionally easy to use and requires only two external resistors, R2’ and R2” (R2= R2’+ R2”) to set the output voltage. Furthermore, both line and load regulation is better than standard fixed regulators. In addition to having higher performance than fixed regulators, this device includes on-chip current limiting thermal overload protection, and safe-operating-area protection. All overload protection remains fully functional, even if the ADJUST terminal is disconnected. By connecting a fixed resistor, R1 the ADJUST and OUTPUT terminals, the LM317 can function as a precision current regulator. An optional output capacitor can be added to improve transient response. Schematic Diagram using LM317   The ADJUST terminal can be bypassed to achieve very high ripple-rejectio...

The circuit may be accustomed charge 12V lead acid batteries. Overview Pin one of the LM317 IC is that the management pin that is employed to manage the charging voltage, Pin a pair of is that the output at that the charging voltage seems, Pin three is that the input to that the regulated DC offer is given. The charging voltage and current is controlled by the electronic transistor (Q1), electrical device (R1) and POT (VR1). once the battery is 1st connected to the charging terminals, the present through R1 will increase. This successively will increase the present and voltage from LM317. once the battery is totally charged the charger reduces the charging current and also the battery are charged within the trickle charging mode. Circuit Notes The input voltage to the circuit should be a minimum of 3V more than the expected output voltage. luminous flux unit 317 dissipates around 3V throughout its operation. Here I used 18V DC because the input. The charging voltage may be set by victi...

A very simple universal battery charger electronic project can be designed using the LM317 voltage regulator and some other electronic components . As you can see in this schematic circuit this charger has extreme few components , but is doing a very good job . When power is applied to the circuit the SCR1 is off, so there is no bias-current path to ground. Universal Battery Charger Circuit Diagram: The LM317 is connected to the battery through diode D1, limiting resistor R1, and bias resistor R2. The D1 diode is used to prevent the battery from discharging through the LED and the SCR when power is removed from the circuit. When LED1 is on, the circuit is in the voltage-regulating mode and when LED1 is off, the circuit is in the current-regulating mode.

This circuit is even simpler and employs a 6V feed from one of the stator connections on the vehicle’s alternator. This is connected to a 6V automotive relay (RLY1) which controls a Continuous Duty Solenoid (RLY2). This solenoid electrically connects or isolates the batteries. When the engine is started and the alternator stator voltage rises, the 6V relay turns on. This turns on the Continuous Duty Solenoid to connect the two batteries in parallel. As long as the engine is running, the vehicle’s alternator will maintain charge in both batteries. Circuit diagram: Simple Battery Isolator Circuit Diagram When the engine is shut down, the alternator stator voltage drops and the Continuous Duty Solenoid switches off, thus isolating the second battery from the vehicle’s electrical system. Provided that camping accessories are only connected to the second battery, the main battery should never discharge. Because the concept is entirely dependent upon the alternator’s stator output voltage, y...