Maker Pro
Maker Pro

Circuit problem

tenmen

Oct 5, 2012
13
Joined
Oct 5, 2012
Messages
13
Can anyone help me, Im trying to build a small 12v portable supply which is recharable, my problem is identifying how to connect it up so I have a flashing LED when connected to AC.
 

davenn

Moderator
Sep 5, 2009
14,043
Joined
Sep 5, 2009
Messages
14,043
hi tenmen
welcome to the forums :)

OK draw out and post what you have already and then we can go from there :)

There are flashing LED's available that along with a current limiting resistor could
be placed across the DC input to the charging cct

Dave
 
Last edited:

tenmen

Oct 5, 2012
13
Joined
Oct 5, 2012
Messages
13
What I have is a 12v rechargable battery, this is connected to a cigarette socket and a rocker switch to turn the unit on.

I have a 500Ma trickle charge which plugs into a mains supply for re-charging the unit, the 12v battery is directly connect to the jack plug socket so it can be charged, is it possible to include a flashing LED which will illuminate only when connected to mains supply and not the 12v battery.

Any help or advice will be much appriceated.

Regards
 

donkey

Feb 26, 2011
1,301
Joined
Feb 26, 2011
Messages
1,301
27384207.png

the easy way of doing it is to run an LED accross the 2 pins with a diode to stop it detecting the battery itself. I hope someone can correct me if I am wrong
if you use the same jack for both the car lighter as you do for the mains then this won't work
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
What I have is a 12v rechargable battery, this is connected to a cigarette socket and a rocker switch to turn the unit on.
What type of battery?

What is the battery's rated voltage, exactly? Is it actually 12V? Some "12V" batteries are actually specified as 13.8V.

I have a 500Ma trickle charge which plugs into a mains supply for re-charging the unit, the 12v battery is directly connect to the jack plug socket so it can be charged, is it possible to include a flashing LED which will illuminate only when connected to mains supply and not the 12v battery.
Donkey's suggestion is good (although it's drawn upside down, with negative at the top, and you need to confirm that the charger output connector is wired with negative on the outer and positive on the inner contact). But inserting the diode between the trickle charger and the battery could affect the battery's charging - it depends on exactly how the charger works.

Do you have a part number for the charger?

The more information and details you post, the more accurately we can answer your questions.
 
Last edited:

donkey

Feb 26, 2011
1,301
Joined
Feb 26, 2011
Messages
1,301
I thought it was upside down. still a newbie but I got the concept right i think lol
 

KrisBlueNZ

Sadly passed away in 2015
Nov 28, 2011
8,393
Joined
Nov 28, 2011
Messages
8,393
Just load the image into an image editor, flip it and rotate it 180 degrees, and you got it right first time!
 
Top