8/16/2019 12v Battery Charger Circuit With Auto Cut Off

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12v Battery Charger Circuit with Auto Cutoff 

This is a simple DIY charge controller schematic posted in response to a

request by one of our readers on our facebook page. The main component of

this auto battery charger circuit is a 555 timer which compares the voltage in

the battery. It turns ON the charger if the battery voltage is below the variable

preset voltage (1 volt chosen here! and turns O"" the charger if the voltage

reaches 1#.$ volt. The battery charging voltage of the charger can be varied by

ad%usting the variable resistor.

Recommented for you:

• LED dot display based Battery charge level indicator circuit diagram

• Simple battery charger circuit and battery level indicator with low battery

recharge alarm

To understand the wor&ing of this 12 volt battery charge controller circuityou must have an idea of the internal diagram of 555. 'ou can refer the pin out

section at the bottom. 'ou must also chec& charge controller using LM32

!" where you can find video demonstration too.

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8/16/2019 12v Battery Charger Circuit With Auto Cut Off

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 Automatic battery charger circuit diagram

Components Required

#$ !" %%%

2$ &ransistor B" %'

3$ Diode ()* +% ,#-../0

$ 1ener diode (%$#0

%$ LED (red, green0

)$ "apacitor /..u,2%

/$ 4esistor (#5 + 3,'2.,2+#.E #.60

'$ ariable resistor #.5 

7$ 4elay #2,#.*

#.$ &ransformer 23.8.9#%,%*

 Working

• :ositive terminal of the upper comparator of %%% is connected with

reference voltage in order to turn ; the charger if the battery charges

above #3$'$

• 4eference voltage is obtained by connecting a

8/16/2019 12v Battery Charger Circuit With Auto Cut Off

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• !f the battery voltage is greater than #3$', comparator output goes high

and =ip =op will be set$ &his turns ; the transistor and the relay$ or

understanding relay working see>ow to connect relay? 4elays working

with animation

• !f the battery voltage is below the preset voltage (set by us0, lower

comparator will reset the =ip =op$ &his turns ;- the transistor and the

relay will switch to charge the battery$

•  &he recharge voltage (preset voltage0 can set by varying the variable

resistor$

• :ower ;- is indicated by a red LED and charger ;- status is indicated by

a green LED$

Components pin out

http://www.circuitsgallery.com/2012/09/working-of-relay-and-connection.htmlhttp://www.circuitsgallery.com/2012/09/working-of-relay-and-connection.htmlhttp://www.circuitsgallery.com/2012/09/working-of-relay-and-connection.htmlhttp://www.circuitsgallery.com/2012/09/working-of-relay-and-connection.html

8/16/2019 12v Battery Charger Circuit With Auto Cut Off

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