PPT Auto Turn Off Battery Charger
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1. Auto turn off battery charger.2. INTRODUCTION
An Auto turn off battery charger is a good option for people who don’t like having to mess with the battery charging process too much
Simply hook our battery up to an Auto turn off battery charger and we will find that it proceeds to charger our battery automatically.
When the battery is charged it will shut off. Hooking a battery up to an Auto turn off battery charger is really easy too.
Simply hook the alligator clips up to the battery posts and leave the Auto turn off battery charger plugged in. A battery will never get overcharged with an Auto turn off battery charger.
Many people choose an Auto turn off battery charger over a manual battery charger can fry our batteries by not shutting off when the battery is charger up.
This can cause a lot of headaches and prevent us from getting the life expectancy out of the batteries we purchase.
3. Operation
In the AC-to-DC converter section, transformer X1 steps down mains 230V AC to 9V AC at 750 mA,
which is rectified by a full-wave rectifier comprising diodes D1 through D4 and filtered by capacitor C1.
Regulator IC LM317 (IC1) provides the required 12V DC charging voltage.
When you press switch S1 momentarily, the charger starts operating and the power-on LED1 glows to indicate that the charger is ‘on.’
4. The relay driver section uses PnP transistors T1, T2 and T3 (each BC558) to Energies electromagnetic relay RL1 is connected to the collector of transistorT1.
Transistor T1 is driven by PnP transistor T2, which, in turn, is driven by PnP transistors T3.
Resistor R4 (10-ohm, 0.5W) is connected between the emitter and base of transistors T3.
When a current of over 65 ma flows through the 12V line, it cause a voltage drop of about 650V across resistor R4 to drive transistors T3 and cut off transistors T2. This, in turn, turns transistors T1 ‘on’ to energies relay RL1.
Now even if the pushbutton is released, mains is still available to the primary of the transformer through its normally open (N/O) contacts.
5. About I.C used in this experiment
The LM 317 is a popular variable ‘Voltage Regulator’.
It is an adjustable 3- terminal positive voltage regulator capable of supplying 100mA over a 1.2 to 3.7 output range.
It is easy to use
This offers full over load protection included on the chip are Current Limit, Thermal Overload Protection and Safe Area Protection.
All over load protection circuitry remains fully functional even if the adjustment terminal is disconnected
it makes an especially simple adjustable switching regulator, a programmable output regulator, or by connecting a fixed resistor between the adjustment and output, the LM317L can be used as a precision current regulator. Supplies with electronic shutdown can be achieved by clamping the adjustment terminal to ground which programs the output to 1.2V where most loads draw little current.
6. Specifications
Vout range 1.25V - 37V
Vin – Vout difference 3V - 40V
Operation ambient temperature 0 - 125°C
Output Imax <1.5A (assuming factory-suggested heat sinking) Minimum Load Currentmax 10mA
7. About relay This is an electrically operated switch . The coil current can be ON or OFF so relays have two switch positions and most have double throw Current flowing through the coil of the relay creates a magnetic field which attracts a lever and changes the switch contacts. These allow one circuit to switch a second circuit which can be completely separate from first. These are designed fort PCB mounting but we can solder wires directly to the pins providing you take care to avoid melting the plastic case of the relay .
8. Advantages A manual battery charger can fry our batteries by not shutting off when the battery is charged up where as this battery charger will never get overcharged with an auto turn off battery charger. This charger provides the full life expectancy out of the batteries we purchase. Easy to use. Simple circuit. Components are easily available and low cost. User friendly product.
9. Applications This battery charger is intended to charger any battery ranging from 0 to 15V. Some of the applications are Rechargeable Cells Motorcycle Batteries Car Batteries Mobile phone charger
10. Conclusion In this report we explained the methodology to charge any battery ranging from 0 to 15V. Using this system when the battery is charged fully it will shut off automatically. The circuit consists of very less components and simple in design. Think of the many ways that we can use an auto turn-off battery charger in our life. Whether we have marine batteries, motorcycle batteries, car batteries or other sources of electricity that need to be charged up, we can count on quality auto turn-off battery charges to add many years of life through the cycling cycles.
11. Thanks.
