Re: UPS as backup power

[Bill Wichers <billw at waveform_net>]

>Someone also mantioned the use of solar cells to recharge the battery. This
>could work however the cost of everything might run you about the same as a
>small as powered generator which could also run your heating, lighting and
>most important keep those beers cold in the fridge ;-)

Solar cells would also need a charge controller and an isolation diode 
since the cells would produce widely varying voltages that would not be 
well tolerated by either the UPS batteries or the UPS control circuitry.

>Most people throw them out when the bateries die. APC sells a wide range of
>replacement batteries however you can find the same batteries for less at
>electronic outlets, it would cost me about $100 to replace the 4 batteries
>in the unit I just received, not bad!

Digikey (http://www.digikey.com) sells the Panasonic sealed lead-acid 
batteries which are EXACT replacements for the batteries APC has been using 
for the past 5 or so years. I have fixed a lot of APC UPSes by pulling out 
the batteries (which is easy on the newer ones that are made to have the 
batteries replaced in the field), pulling off the wiring harness, fuse 
holder, and "sticky handle", and assembling a new battery pack with 
DigiKey-bought batteries and the wiring components from the dead battery 
pack. Cost to service the SmartUPS 700 rack-mount units is about $35, each 
battery is about $17 (excluding shipping). A full set of batteries for the 
older SmartUPS 900 is around $80 or so. The replacement procedure is very 
easy, you just order new batteries using the manufacturer part number on 
the old batteries (usually starts "LCR-<number>"), and then wire the new 
batteries in the same way with the same parts as the old battery pack.

Note that for some of the little UPSes there is only one 12v battery 
inside, so a fix might not even be $30 total WITH SHIPPING! Very cheap.

>As for now the new little unit is small and easy to hide behind the tank and
>I feel safer knowing my filter is backed up. Hopefully I will not experience
>a blackout long enough to cause a heat issue.

Last year we had some winter storminess around here that prompted me to 
tell some coworkers that if I lost power at home I'd bring batteries to 
work to charge and take them home to run tanks. We have a 500 kW diesel 
generator running our datacenter (one of several behind the building we're 
in) with a contract for refueling. Luckily I haven't had to leech 
tank-power from it... yet ;-)

BTW, for anyone who's really serious about backup, Home Depot has been 
selling the Generac standby generators (which are made for outdoor mounting 
and include an automatic transfer switch) for *very* good prices. They run 
on propane or natural gas, and if you have a lot of power failures one of 
those units could run your system indefinitely if necessary. They are nice 
units in sound-dampened outdoor enclosures and come as a kit with all the 
stuff needed to install them. I think the 8kW unit is about $2800 or so. 
Costco has had them at good prices too.

         -Bill
*****************************
Waveform Technology
UNIX Systems Administrator