Local made UPS for computers


I have a very specific question regarding local made UPS for computers. I am assuming that we all know the basics of UPS available in local market. I am trying to build UPS for computers which could give 3 desktop computer systems and 2 laser printers full 9 hours of electricity.

As it is fact of life now that there is just nothing can be done about electric blow outs and load shedding so there is no use of bitching around about that I have just accepted it as part of life.

so the other sources of power left for me are generator and UPS in the absence of electric company electric.

generator is very costly to run on petrol given the oil prices and secondly its will be very expensive to maintain if in terms of mechanical maintenance if its ran for 9 hours on daily basis,

foreign UPS like APC and other chinese dry battery types are just too expensive for the purpose i want to use for. so they are out of question too.

NOW THE MAIN ISSUE: I know that the concept of regular home UPS and computer is the same only difference is the switching only

A: regular UPS switching has a slight delay in fraction of a second before it goes to battery power when regular electric goes out, well its ok for fans and lights but this delay is too long for computers and they get reset and boot all over again and any work on computers will be lost.

B: since computer UPS has ZERO DELAY SWITCHING of some sort so when UPS switches from electric company power to batteries computer stays on as they are getting continuous power.

bottom line is this I want to use our local ups with truck battery combination with if any for computer switching mechanism available locally made etc. any suggestion would be appreciated.


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I am trying to build UPS for computers which could give 3 desktop computer systems and 2 laser printers full 9 hours of electricity.

It will take forever to charge man…I think you are better off with a generator if you need that kind of up time…


It's not just the switching delay, but the square wave output for local UPS, which freezes the computers. Your option would be to get a near sine-wave output or sine-wave output UPS, which will definitely cost you more than the normally available UPS. For 3 computers and 2 printers, you'll need approximately 5kVA, and then it should run for 9 hours straight. Man, you are asking for too much. It might cost more than 100K just for batteries.


The "imported" good-quality UPS units have several plus points that some of the local units do not, these include:

(1) As mentioned, near-sine-wave or sine-wave output, which is critical for electrically sensitive components.

(2) Online Power Paths, i.e. that even when on KESC, the UPS draws power out of the battery, and the grid feeds the battery so that no switching occurs when the power drops out.

(3) High-range voltage regulation, which means that that UPS is constantly refining the power output to within a few point of ideal - not just while on battery, but all the time.

(4) Cold-starting, which allows computers and other heavy load equipment (like laser printers) to draw more power than their normal when starting.

(5) Batteries; the batteries that are bundled with APC units etc.. are maintenance-free batteries, often gel-based, which are more expensive and more durable as opposed to simple, sealed batteries which you can find often installed in cars here (don't confuse them with wet or marine batteries).

My suggestion is that if you want something cheaper than the imported, you look at some of the better UPS manufacturers available here such as Saltec.


What do you mean by 'computer switching mechanism available locally made' I thought you could get locally made UPS's for computers, or is it when you buy them they are actually for lights and fans and you need to change a part of the mechanism?