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have you done the computations for your power needs?
how much time do you want to be able to run on UPS?
typically the time you need is either just enough to safely
shut down your machines ( 5-10 minutes ) or long enough to run servers
without power for several hours. something in between is usually
not needed.
what is your total load and how many kwh do you need?
for about $1000 you can build a system that will be 10 times better
than any box ups and can run your machines for up to one day
without power or whatever you like. for $2000 you can easily build
a system that you can run all your typical household on for a day without
recharging. for $3000-$5000 you can permanently disconnect yourself from the powergrid
and go self powered. so it all depends on your needs.
typical system will consist of a couple 200 AH batteries and inverter/charger.
then it all depends on how many batteries you want to hookup, if you hook
up 2-3 then you can get about 4-6 kwh, typical small household uses less
then that.
typical ups backups only allow up to 30 minutes of standby power, just enough
to shut the equipment down or start a backup genset.
if you have a trading office then best place to lease is place with generator
backed up power. they do have those buildings, you just need to ask the
landlord.
problems with most ups is that they lose capacity very quickly if you
don't do deep discharges on em once a quarter, because unused or
charged batteries will get sulfated on you very fast. the pointer is
discharge your ups to 30% left every quarter, ie you need to give your
battery a workout once in a while.
another trick is, get a 500VA backup and take battery leads out and
hook them up to a large battery, you just added wh capacity,
hooking up more batteries in parallel you can gain whatever capacity you need.
finally take a look at the specs carefully:
***
Typical backup time
at half load 33.3 minutes (400 Watts)
***
basically tells you that it will run a single computer + 2 crt monitors for about 30 minutes,
what it's really telling you is that it's probably half that time ie 15 minutes.
i don't see 40 hours anywhere there.
so be careful with what they claim.
and yet finally, some ups backups have genset start outputs, but your genset
must have auto-start system. what happens is ups senses power failure and
starts genset automatically for you after x minutes of no power, then there are
system that will e-mail you or call you and tell you that your power is down.
it then depends on your fuel tank capacity and gas prices :)
bilo.
----- Original Message -----
From: Mark Brown
To: omega-list@xxxxxxxxxx
Sent: Wednesday, May 01, 2002 12:06 PM
Subject: Re[2]: Boat Load of Backups
Hello Jeff,
JM> I have had good luck for many years buying used UPSs on ebay. Not
JM> the little 500VA crappers, but nice big units that we use for our
JM> servers.
the below combination was suggested by someone on the list. i like it
apc says it will run a flurry of stuff for 10 hours or a single
computer and some stuff for 40 hours. i could fly back home and start
the generator myself if i had to. downside is total cost at best is
1300.00 and weight about 300 pounds, oh my back. guess i will be
throwing a battery backup party soon, who wants to come help.
http://sturgeon.apcc.com/techref.nsf/docID/D81C90003390C9E1852566F0007F6EF3/$FILE/D0191B3.pdf
http://www.apcc.com/resource/include/techspec_index.cfm?base_sku=SUA1000XL
if they make a weather proof model i could just let it set out side
but with my luck lightening would hit it. ok looking at google now
for storage sheds and lightening rods.
--
Best regards,
Mark mailto:markbrown@xxxxxxxxxxxxx
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