UPS Battery Life

[BobH]

Does anyone here know about the life of batteries in, for example, an APC UPS electronic surge protector and battery backup?

If these units are always connected to household 120VAC and seldom ever experience grid power failure, why do the batteries go bad? And why do the units block power when the batteries fail?

As any EE here can tell, I know very little about this technology. (I'd say that I now nothing about it except that I do know how to plug things in and how to recognize when there is no longer any power. )

[Hey Jude]

http://www.apcc.com/solutions/display.c ... tryCode=us

According to APC all their batteries last from 3-5 years so that helps with one part of your question.

Here are some FAQ about UPS which will give you alot of background and might help ya until someone else chimes in with a very concise answer http://www.jetcafe.org/npc/doc/ups-faq.html

A friend of mine wrote this and I followed his instructions about UPS:

"... The only things that should be plugged into the UPS is the computer and its peripherals. This way, all you have to unplug is the UPS. All UPS have outlets that are only surge protected as well as outlets that are battery backed up. Try to keep only the computer itself and the monitor on the battery back up side that you can interact with the system if the battery kicks in. Also, if the UPS comes with a Software CD and a USB cable, you set it so that when the battery does kick in, it waits a predetermined amount of time or until a certain amount of power is left in the battery, to automatically shut everything down and power off the system. This way, if you are not home when an outage occurs, you don't have to worry about losing anything."

[BobH]

Thanks, HJ!

I had clicked around the APC site and saw the 3-5 years thing. What I don't understand is why the batteries fail if they are not used often because the grid power is reliable. We're talking regular household ambiance which means relative humidity is pretty consistent and not too high and ambient temperature is between 68-74 degrees Fahrenheit.

Just the cat's curiosity revealing itself.

[Hey Jude]

Here's another site I had bookmarked from another forum that explains more in detail about what discharges battery life
http://www.batterywholesale.com/batinfo.html

In a nutshell,
"There are four major factors that affect UPS battery life (both sealed and flooded cells):

* Ambient temperature
* Battery chemistry
* Cycling
* Maintenance and service ....

"...UPS Battery Chemistry

No UPS battery will last forever-- even one that experiences minimal use. This is because UPS batteries are electro-chemical devices whose ability to store and deliver power slowly decreases over time. So, even if you follow all the guidelines for proper storage temperature and maintenance, you still must replace them after a certain period of time...."

[BobH]

Great link! Thanks again!

That was precisely the sort of information I was seeking. Those folks are just down the road from me - about 50 miles.

[Hey Jude]

Great link! Thanks again!

That was precisely the sort of information I was seeking. Those folks are just down the road from me - about 50 miles.

I thot you might like that one. It explains in detail how it all functions and takes the guess work out of it. You're very welcome Have a great evening as I'm calling it quits for the night