UPS Circuit

[E2K]

I've got two batteries 12V 12Ah . I want to use them in an ups for my pc (pIII). Only for CPU.Did some one have a circuitfor it. Or how i can connect them directly to PC ?

 

[charmer]

i am also looking for somehting similar to this..

 

[ronsimpson]

E2K & charmer,

Questions,
I want more information on your PC. Is it a laptop or a desktop. 110 or 220 ac?
E2K I think you want to just power the PC and not printers and monitor while I believe charmer wants to power the PC and monitor.

You can buy a UPS supply! Problem solved.
You can make a UPS with car batteries and a 12 volt inverter.
Do you really want to build a 12 volt to 110Vac inverter. (please say that in beyond your experience)

 

[raviram87]

This circuit is a simple form of the commercial UPS, the circuit provides a constant regulated 5 Volt output and an unregulated 12 Volt supply. In the event of electrical supply line failure the battery takes over, with no spikes on the regulated supply.

The secondary winding should be rated at least 12 Volts at 2 amp, but can be higher.

LED 1 will light ONLY when the electricity supply is present, with a power failure the LED will go out and output voltage is maintained by the battery.

 

[rif_sun]

goodddddddddddddd

 

[Super_voip]

How long do you want the computer running a few miutes? that battery is going to take a long time to charge with a 220ohm resistor, the 5V regulator will take the brunt of tha shutdown as most harddrives use just 5V these days and the CPU/RAM is powered from the 5V as well. With a "simple" 5V 5Amp linear reg running at 5Amp (5x5=25watts) you will be losing 35watts as heat (7x5). With the size battery you do have it probably won't be a big problem as power is concerned, just look out for those hot heatsinks