Required Part List
1. 12v DC operated relay which can handle 5A 22o/240 AC ( i used omron relay made in malaysia from stadium @ 100taka. The relay base (50taka) is precisely made for this relay)
and 5A 28V DC.see the pix for full spec. The relay i used consists of 4
set of Slots. completely seperated from each other
2.A relay base to make the mod more professional and safe.
if u cant find the base or dun want to spend 50 taka then u must solder all the the points by urself. (which i dont recommand)
3.1 Feet wire X 4 ( make sure they are thick enough to carry 500to 600 watt of electricy or above or according to ur wattage requirement)
the choice is urs.
tools required for the mod.
1. total 10 fingers.
2.star screw driver.
3.Soldering iron => for soldering cable joints
4.Digital Multi Meter
Optional tools: handy but not exclusively required.
1. IN4001 DIODE
2. Spare PSU for test purpose only.
3. electricity tester ( the typical tester dat we poke in the socket to check electricity)
Step1: 1st try to identify the power switch in ur UPS. this switch is responsible to turn on/off the UPS.
take a look at the PIX to identify this switch fuction.
in my case 1&2 (set1) is for AC and 3&4(set2) is for turning on/off speaker(beep beep nd other functions) signaling.however both set needs to be turned on and off together.
so u can not or should not turn on set 1 while keeping set 2 off. or vice versa.
In your case things might be even more simpler. (u mi8 have the switch woking for AC only). So, inspect urself.
Step2: Now that u have understood the power switch. U need to connect 2 piece of wire to 1 and 2 .see the pix.
Now connect 2 wire to 3 & 4.
All THE CABLE JOINTS MUST BE SOLDERED TO AVOID LOOSE CONNECTION.
So in total ull have 4 wire coming out from the UPS. (1,2)and (3,4)
(i have 6 wire. becaz i connected two wire for 2 and two wire for 1 so dat i can utilize 1 extra slot on the relay for redundency purpose[optional])
Step3: 1.0 Now take a look at the relay with pin numbers crafted on the bottom of it.
follow the pictures which should be able to guide u through.
Step3:1.1 (optinal) when a relay looses power the megnetic coil discharges elctricity that goes back to PSU. We dont want that. But modern PSU should be able handle this quite nicely.
Still im using it ...just in case...as a safe bet.
(Its better if u can find a relay which has a resistor or diode built-in. u can aviod step 3 if u can find these.)
anyway in order to protect the psu from relay backfire voltage u have to connect a Diode (IN4001) between the 12V line which will be powering the relay. Follow the layout on the
So, if every thing is done properly, 1st turn the power switch of UPS to ON and turn ur PC ON which will pass 12V to relay and the relay will short the 1,2 and 3,4 (they r
already shorted since u manually turned the UPS switch on just a while ago. So once the PC is on u can safely turn the UPS switch to OFF but ur PC is still running since the
role of UPS power switch is shifted to relay and the relay is in ON mode. NOw when a shutdown is initiated by the UPS software or any other software or manual shutdown , the UPS will only turn off after the PC shutdown.
For those who dont have a UPS monitoring software to initiate shutdown on power failure can go for 1 additional MOD which ill discuss later on.
That is all for now. and ill be glad to to assist u if u still need any.
Thnx for going through this DIY.