• Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

help,i can't find the auto shut off handphone battery charger circuit!!

Status
Not open for further replies.

lazyhut

New Member
my sch ask me to make a auto shut off handphone battery charger..but in google, yahoo, etc..i cannot find the suitable circuit..i have done 2 project from google previous, but all cannot work also...

i'm having problem with finding the circuit, would anyone do me a favour..help me figure out a functionable circuit..

abstract: the idea is to be able to shut off the battery charger power when hand phone has been fully charged..


below is the circuit what i done previous, but cannot work..someone help me check what is the problem..since the circuit not complete



http://www.electro-tech-online.com/custompdfs/2009/05/Circ01-Feb05.pdf
 
Last edited:

audioguru

Well-Known Member
Most Helpful Member
The circuit from the website in India is extremely old. It over-charges old Ni-Cad batteries, it is not a charger for the modern lithium battery in a cell phone.
 

Hero999

Banned
Aren't you supposed to design it yourself?

Isn't that the whole point of an assignment?
 

lazyhut

New Member
The circuit from the website in India is extremely old. It over-charges old Ni-Cad batteries, it is not a charger for the modern lithium battery in a cell phone.
can u help me modify the circuit into lithium battery charger..i still newbie in these things..
but my sch start to ask us to find a circuit from website and make a auto shut off handphone charger
 
Last edited:

audioguru

Well-Known Member
Most Helpful Member
Ask your teacher to teach you about the details of charging a modern lithium battery.
More information is on the datasheet of a battery charger IC from semiconductor manufacturers.
More information is available at the website for The Battery University.
 

lazyhut

New Member
Ask your teacher to teach you about the details of charging a modern lithium battery.
More information is on the datasheet of a battery charger IC from semiconductor manufacturers.
More information is available at the website for The Battery University.
my lecturer don't want to teach, he said this is a project..
ask us find in internet..:(:(
 

audioguru

Well-Known Member
Most Helpful Member
Your teacher should tell you about the dangers of charging a lithium battery incorrectly. It can catch on fire with an extremely hot flame. Water on the fire makes it burn hotter.
Or maybe your teacher still has an old cell phone that has a huge and heavy old Ni-Cad battery.
 

lazyhut

New Member
Your teacher should tell you about the dangers of charging a lithium battery incorrectly. It can catch on fire with an extremely hot flame. Water on the fire makes it burn hotter.
Or maybe your teacher still has an old cell phone that has a huge and heavy old Ni-Cad battery.
my lecturer never tell us - -"" he just told us go back search website and get the circuit and make it...just like tat only..all people different project..
now i just know the dangerous of the lithium battery...:p
can u help me modify the circuit..
 
Last edited:

audioguru

Well-Known Member
Most Helpful Member
Simply use a battery charger IC and set it for charging a lithium battery.
 

lazyhut

New Member
mr,audiaguru..the pic above if i change my transformer to 6V izzit suitable or not ??
if i change to 6v the other components have to change or not ??

the output should use how much to charge the lithium battery ??
 

audioguru

Well-Known Member
Most Helpful Member
The absolute max charging voltage for a lithium battery cell is 4.2V for most of them or 4.1V for some of them. The charging current must be limited to the spec for the battery. The charging must be disconnected when the charging current reduces to 3% of the rating of the battery cell.

The charging current must be limited to a small amount if the battery has been discharged too low.

The Battery University website tells you all this stuff.
 
Status
Not open for further replies.

Latest threads

EE World Online Articles

Loading
Top