Aaron's Homepage Forum
Aaron's Homepage Forum
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password
Forgot your Password?

 All Forums
 Electronics
 Auto
 car charger using pc power supply
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

tikbalang
Apprentece

Philippines
21 Posts

Posted - Jan 13 2010 :  06:49:49 AM  Show Profile  Visit tikbalang's Homepage  Send tikbalang a Yahoo! Message  Reply with Quote
can i use a pc power supply for an 12v car battery charger? what mods/additional circuit will be needed?


sergiosparks
Apprentice

Philippines
132 Posts

Posted - Jan 14 2010 :  09:42:09 AM  Show Profile  Send sergiosparks an ICQ Message  Reply with Quote
yes why not ,yellow and black is 12v regulated it will shut down your
power supply if it senses that you have a very drained battery put a series resistor about 10 ohms or a brake light as voltage regulator.It will be a lot of waiting though...
Go to Top of Page

Aaron Cake
Administrator

Canada
6718 Posts

Posted - Jan 16 2010 :  10:37:13 AM  Show Profile  Visit Aaron Cake's Homepage  Send Aaron Cake an ICQ Message  Send Aaron Cake a Yahoo! Message  Reply with Quote
No. An automotive lead acid battery needs more then 12V to charge. It needs to be charged at 13.8V at least, 14.2 or 14.4V is better.
Go to Top of Page

tikbalang
Apprentece

Philippines
21 Posts

Posted - Jan 17 2010 :  11:38:16 AM  Show Profile  Visit tikbalang's Homepage  Send tikbalang a Yahoo! Message  Reply with Quote
i found a mod:

http://www.mp3car.com/vbulletin/power-supplies/31652-car-power-supply-battery-charger-old-pc-supply.html


But they dont work too well as a battery charger as the open circiut voltage on these switch mode supplies is just that, 12v. But you can change that

if you look at the yellow wire to the circiut board, somewhere along that track it has to lead to two resistors, in a T config. One goes to ground, one to the 12v. and the connection between goes to the regulator chip, (power supply controller) 
If you change one of these resistances values, you can set your output voltage higher. Typicaly you would set it to 13.8v


comments?


Go to Top of Page

Aaron Cake
Administrator

Canada
6718 Posts

Posted - Jan 30 2010 :  10:31:05 AM  Show Profile  Visit Aaron Cake's Homepage  Send Aaron Cake an ICQ Message  Send Aaron Cake a Yahoo! Message  Reply with Quote
Good info, I didn't realize it was that easy to change the voltage of a typical computer power supply.

Two things to watch are they probably don't like power being applied to their outputs when switched off, and of course you will have to monitor charge voltage.

It may be easier and just as inexpensive to build an automatic charger like the one at http://www.aaroncake.net/circuits/charger2.asp
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
Aaron's Homepage Forum © 1995-2020 AARONCAKE.NET Go To Top Of Page
This page was generated in 0.08 seconds. Snitz Forums 2000