Transcript Auto turn off battery charger

Auto turn off battery
charger
INTRODUCTION
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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.
Circuit diagram
Operation
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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.’
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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.
About I.C used in this
experiment
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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.
Specifications
 Vout range 1.25V - 37V
 Vin – Vout difference 3V - 40V
 Operation ambient temperature 0 125°C
 Output Imax <1.5A (assuming factorysuggested heat sinking)
 Minimum Load Currentmax 10mA
About relay
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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 .
Advantages
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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.
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
Conclusion
 In this report we explained the methodology to
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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.
Thank you