i saw this cct in circuit gallery and i have some question about it

1-what will be the voltage on( cv or pin 5)coz it internally connect to voltage divider
2-i think red led always on ..then what is purpose of it ?

http://www.circuitsgallery.com/2013/04/automatic-battery-charger-controller.html
Working

• Positive terminal of the upper comparator of 555 is connected with reference voltage in order to turn OFF the charger if the battery charges above 13.8V.
• why they said Positive terminal ?????? i think ( cv or pin 5) is negative terminal

 

It is another stupid circuit concocted by a newbie. The use of a 555 as a Schmitt-Trigger is not novel.

How long do you think it will take to recharge a standard 65Ah automotive battery by passing the current through a 5Ω resistor? It's maximum current delivery will be about 200mA.

 

Definitely one of the poorer ones I've seen...

200mA isn't even sufficient for trickle charging; let alone charging hard enough and long enough to minimize sulfation.

 

i saw this cct in circuit gallery and i have some question about it

1-what will be the voltage on( cv or pin 5)coz it internally connect to voltage divider
2-i think red led always on ..then what is purpose of it ?

1- V at pin 5 = zener voltage = 5.1V
2- It is here to indicate that the charger is on, i.e connected to the power and not related to batt state

 

It's maximum current delivery will be about 200mA.

...if it survives having a 555 supply voltage greater than the rated absolute maximum.