Premises Security (part 10) Power Protection and Security
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An Example CalculationFollowing on from my last entry, let's work through an example of estimating your UPS size..
* Your security panel is a wireless model.
* It does not support the addition of external batteries.
* It has an internal backup battery which is stated to support the system for 2 hours.
Note; unless otherwise advised, the battery spec is always based on new batteries.
Battery LifeAll rechargeable batteries loose their ability to support load as they age, regardless of whether they are kept "fully charged" or not.
Depending on the type* of battery, this decline will start to become apparent any time from about 2~3 years onward and accelerates each year thereafter.
For example, a Sealed Lead Acid (SLA) battery will be nearing end-of-life after about 4~6 years
* Your panel has an external power-pack which has a rated output of 12V 1.5A.
Volts x Amps = Watts so 12x1.5=18W
Now it is entirely unlikely that your system will actually draw this much power, but if you can't find the rating visible anywhere on the system and don't have a manual which lists those specs, then run with the above as a rough estimation.
Decide Your "Run-time"Now let's say you want to be assured that your system will operate for a full 24hrs without electricity.
Again using VERY rough calculations, 18W x24hrs = 432W required.
Build in a value for Power Factor of 0.04 and you'll need approx 450W.
Remember too that the batteries will start to loose their capacity after the first couple of years so build in some redundancy there too.
My rule-of-thumb is either double or at-least half as much again as your calculated requirements.
Given that we're talking about a very small UPS in this example, let's double our requirements so 450W x2 or 900W.
Now it's shopping time.
Preferred UPS Brands
Although there are many brands of UPS on the market, my experience of selling, installing, servicing and refurbishing power security devices such as these, has led me to favor three brands.
Powerware, APC, Emmerson.
Although you could now break-out the search-engine and do some research, searching for "UPS" can be somewhat frustrating, as that sequence of letters is used by a lot of NON-electronics related companies. (Eg. United Postal Service)
Probably the easier way to start your research is to select from some of the ads you'll find in this blog
Common RatingsAs you do your research, you'll find that UPS' come in "common ratings"
Typically these are;
100;150;300;500;1000;1500;1750~1800;2000~2200,3000;5000VA and upward.
Two Price Scales
You might also notice that there are two different price ranges for roughly the same VA ratings. For example one 2200VA may be $1600 yet another 2000VA may be $2500! Why?
Because there are different types of UPS.
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An Example CalculationFollowing on from my last entry, let's work through an example of estimating your UPS size..
* Your security panel is a wireless model.
* It does not support the addition of external batteries.
* It has an internal backup battery which is stated to support the system for 2 hours.
Note; unless otherwise advised, the battery spec is always based on new batteries.
Battery LifeAll rechargeable batteries loose their ability to support load as they age, regardless of whether they are kept "fully charged" or not.
Depending on the type* of battery, this decline will start to become apparent any time from about 2~3 years onward and accelerates each year thereafter.
For example, a Sealed Lead Acid (SLA) battery will be nearing end-of-life after about 4~6 years
* Your panel has an external power-pack which has a rated output of 12V 1.5A.
Volts x Amps = Watts so 12x1.5=18W
Now it is entirely unlikely that your system will actually draw this much power, but if you can't find the rating visible anywhere on the system and don't have a manual which lists those specs, then run with the above as a rough estimation.
Decide Your "Run-time"Now let's say you want to be assured that your system will operate for a full 24hrs without electricity.
Again using VERY rough calculations, 18W x24hrs = 432W required.
Build in a value for Power Factor of 0.04 and you'll need approx 450W.
Remember too that the batteries will start to loose their capacity after the first couple of years so build in some redundancy there too.
My rule-of-thumb is either double or at-least half as much again as your calculated requirements.
Given that we're talking about a very small UPS in this example, let's double our requirements so 450W x2 or 900W.
Now it's shopping time.
Preferred UPS Brands
Although there are many brands of UPS on the market, my experience of selling, installing, servicing and refurbishing power security devices such as these, has led me to favor three brands.
Powerware, APC, Emmerson.
Although you could now break-out the search-engine and do some research, searching for "UPS" can be somewhat frustrating, as that sequence of letters is used by a lot of NON-electronics related companies. (Eg. United Postal Service)
Probably the easier way to start your research is to select from some of the ads you'll find in this blog
Common RatingsAs you do your research, you'll find that UPS' come in "common ratings"
Typically these are;
100;150;300;500;1000;1500;1750~1800;2000~2200,3000;5000VA and upward.
Two Price Scales
You might also notice that there are two different price ranges for roughly the same VA ratings. For example one 2200VA may be $1600 yet another 2000VA may be $2500! Why?
Because there are different types of UPS.
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posted by Col. Sanders | 8:50 AM
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