Long Lasting Battery Backup

I need to know what battery backup can keep a whole server up for about 1-2 hours straight. THanks!
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grbladesConnect With a Mentor Commented:
Hi brianhilfiger,
You can either go for a large UPS or get a smaller one and a backup generator. It depends if someone is going to be around when the power fails to start the generator.
If you want to use a UPS Then I suggest you look at something like the APC 3000VA model.
I use a TrippLite Internet 700 UPS for my home computer.  I have twice used it for 50 minutes after the power has failed with no problems.  My computer is a 225 MHZ Winchip2 system with 128Mb RAM, a CD drive, a CD-RW drive, three floppy drives, two hard drives, three fans, and a 17" monitor.  All I have plugged into the UPS is the system and the monitor, no peripherals.  If you need a printer, get a seperate UPS for it.  If it is an impact or laser printer, allow for the power surges required by the printer's technology.  For instance, a laser printer might draw 1500 watts for a very short period of time.

The most important trick to powering a computer system for long periods of time is to pay attention to the UPS specifications.  In general, 1000 VA (or larger) would be the size I would recommend for a server.  It all depends on what you call a "server".

First determine how much peak power is needed to keep the server running.  My general recommendation (rule of thumb) is to take the calculated watts and buy a UPS with double the VA.  If you calculate 500 watts, go buy a 1000 VA UPS.  If you look on the UPS manufacturer's internet sites, they will tell how many watts each UPS will power and for how long they will power a full load and a half load.

There are many UPS manufacturers and many different technologies used to convert DC battery power to "normal" AC power.  You must pay attention to the "efficiency" of the conversion.  Some more efficient conversion units get away with using a smaller internal battery and will not last as long as a less efficient UPS with a larger battery.  The basic trick is to get the UPS with the largest battery that you can afford.

If you are going to use this system in an accedemic or industrial environment, you can also get a UPS that uses an external battery (or multiple batteries) to extend the up-time (with appropriate installation).  If you want to use the system in a residential environment, then external batteries may be against the law in your area.  Check with your local building inspector or code enforcement officer.  Failure to do so may invalidate your home owner's insurance.  Regular automotive batteries pose a safety and a health hazzard inside a residence without proper ventilation.  You don't want to be poisoned or have the battery blow up on you.  Sulfuric acid can be dangerous.

A generator is normally not a good solution if you only want to power a server.  If other critical euipment needs to be powered, then I would consider a generator with an AC-to-generator cut-over package to avoid any power interruptions.  The added package uses a UPS to allow for momentary power fluctuations and starts the generator after a time delay.
Any more questions?   .........     Bobvc99


DO NOT (repeate)  DO NOT plug one UPS into another UPS in order to lengthen the up-time!!!!  This opens you up to several safety and legal problems and will cause trouble.  In theory (at first glance) it seems like a simple solution but, in operation, there are problems you don't want to get into (like batteries blowing up from inductive surges).  I am not going to explain all the problems here.  I have already written too much.

Also bear in mind any battery runtime information is for new batteries only. Batteries normally need replacing every 3-4 years as at this time their runtime is significantly reduced.
brianhilfigerAuthor Commented:
Thank you all that was very good information!
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