Power Prob?

[koushik401]

i just got a new pc with 600-watt Thermaltake smps i had 1 old ups that i used for my old pc now i connect my new pc to it and it was little old so i just replace its battery with a new 12v 7amp  but now if my main power goes out my pc just stop not run for few min to shut down is it ups problem

on my ups i had my monitor and my pc cabinet and my monitor is like take max 15watt 

i dnt know how much load my ups rated

and if i had to buy new ups what should i ask at shop cause online some like 600va and stuff  and what kinda ups i need for my setup (600watt smps and a monitor)

[Olaf6541]

With 7amp do you mean 7Ah? Because if its only capable of delivering 7amps at 12V thats 84W and probably not enough for your pc. And a pc with monitor is well over 15W, probably even over that 84W.

[mariushm]

A GOOD 12v 7Ah can probably deliver around 2-300w for 5-10 minutes. Basically a UPS with such a lead acid battery can probably produce around 100-150w for 10-15 minutes before it shuts down.

 

For example, see the datasheet of this battery : datasheet

 

 

That line says the battery will go down to 1.8v per cell (so 6x1.8v = 10.8v) in approx. 1h if you consume around 50w, 30 minutes at 90 watts and so on...

Keep in mind the actual power inverter in the UPS is around 80% efficient, and the power supply itself is only around 80% efficient... so if the components in your PC  need 100 watts to run, the UPS may actually take 110-120 watts from the battery.

 

However, I suspect your problem is somewhere else ... the new power supply probably has a very small capacitor at the input,and it stores too little energy to continue to run without power if there's any hiccups.

Your UPS doesn't switch instantly to running on battery, it needs a bit of time to react and turn on its electronics and provide AC voltage out of it... it may take 10-20 milliseconds.

A regular ATX power supply is supposed to have capacitors big enough to hold energy for at least 16 milliseconds, but some have as little as 8-10ms.

 

Also, some power supplies are more sensitive to UPSes that don't have an AC output with pure sinewave... cheap UPSes output simulated sinewave which is harder on computer power supplies .

 

You could try to solve the problem by replacing the primary capacitor inside with a bigger one but there's no 100% guarantee it would fix it, and in general these are expensive if you buy just one, like 5-10$ expensive - power supply makers get the prices down to 1-2$ because they're buying tens of thousands of them.