Hello.

Does anyone know how to connect up a few UPS to supply power to servers?

Meaning if I have 3 UPS how to I make them all act as if there is one overall power supply.

Anyone have any ideas?

to my knowledge that is not possible without something to connect them all.. the correct way to do it is buy a an extra battery pack that will connect to the UPS to give it extra life. I know the bigger APC ones have that option to daisy chain extra battery packs

Originally posted by zupanm
to my knowledge that is not possible without something to connect them all.. the correct way to do it is buy a an extra battery pack that will connect to the UPS to give it extra life. I know the bigger APC ones have that option to daisy chain extra battery packs

But a UPS cn only support a certain amount ot watts...
I saw something like a power regulator that eats power from a power outlet and with a redundant power from a UPS but I have no idea what it was... nor do I know how to use it as we don't see this in our regular computer store :P

Any ideas?

are you looking to get more life when the power goes out for the servers attached to UPS or attach more servers to a ups

I am looking to attach Multiple UPS to supply a larger output in turn making my servers run longer in case of a power failure :)

creating a "larger" output will not keep them up longer.. you need to add more battery life.. the only realiable way to do it is get a UPS you can daisy chain external batteries too.

Here are the rack mounted ones we use where i work
http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SU3000RMXL3U

on about half load that provides around 20 minutes of backup time.. not that good.. so what we do with mission critical machines is attach a battery pack to that UPS to extend uptime in a power outage.

the product number is SU48R3XLBP you can see a chart of uptime with that unit plus the number of battery packs you want to daisy chain to the main ups unit

http://www.apc.com/resource/include/ups_runtime_chart.cfm?base_sku=SU3000RMXL3U&family_id=164

that is the only realiable way to go about it.

the only realiable way to do it is get a UPS you can daisy chain external batteries too

What do you mean??

My servers are low Watts comsuming type so on a 2200w UPS one unit can last up to 2 hours. But my problem is that I got more than a dozen servers :P and I got 3 individual UPS units.

Well if there is no way of linking them up I would just have to do what I am currently doing.
1 UPS to Main Server
2 UPS to the rest

I just don't understand what is a Daisy Chain :P Is it linking the Power in to the power out of another unit? and then setting them up as a chain?
Wouldn't there be earthing issues?

no it has nothing to do with connecting more UPS.. it is taking a UPS.. and certain UPS have a attachment in pack to attach muliple battery packs to increase lifetime of the servers on the UPS.. its adding more battery power to 1 UPS. With these UPS's you can connect up to 10 extra battery packs to them to increase the lifetime more then 10x

Oh. I think I get it :)
Guess i would have to stick with my current solution until I get a much more powerful UPS for my servers then

Thanks for your help.

Where do you have a dozen servers which doesn't already have long term standby power? :confused: :eek:

I wouldn't oversize UPS's for extended run times because batteries are expensive and you'll never have enough run time for serious (whole day) outages. Get UPS's which cover "typical" outages (which you seem to have already) and install a gas/lp/propane generator on an automatic transfer switch to provide for extended downtimes.

The country the servers are in don't experience such long hours of outrages. Because the country is so small, a power cut could mean half the country being in total darkness or worse yet the whole country :P.

The longest and most serious power outrage in our history was like less than 2 hours :) Which we are well prepared for.
I am looking into a generator solution for long term outrages but still am calculating if the cost VS usability would verify my purchase.
Because for all I know, it may never come into use and having it only gives me the psychological assurance.

Currently the UPS are there more for standingby in case of a surge instead of a power cut.

Anyway what kind of generator would you suggest?
Quiet, clean and cost effective and able to supply up to 4000 - 5000 watts of power.

i mean you can get any normal gas generator and hook it inline in your power system.. you'd need a professional to do that though.. they aren't mean to have computers hooked up to them but the ups will stop surges and low voltage events.

once the power goes out your UPS will kick in just like it should.. from there you can power up the generator and that will supply power to that circuit and then the ups will go on normal mode..

I wouldn't be able to recommend a specific generator because my hosting relies on our datacenter's power for that and my home generator (Coleman Powermate) isn't what I'd call "robust" :). A 5kw generator should be cheaper than 2 hour battery run time... though an automatic transfer switch and other connection considerations will cost some $$ as well.

The thing I'd worry about is stable voltage. Cheap generators aren't known for putting out voltage that UPS's will run on and you may have to change the UPS's sensitivity settings or introduce a "phantom load" to get them to work together.

hummm.... Then I would have to look into my local generator store to check out the possibilities.

But there is something I am not sure of...
That is a Generator would provide DC current right? But the UPS recieving end is for AC currents. Would'nt that blow it?

no.. home generators provide ac current... like the ones to power a home when the power goes out anyway. There are a lot that do DC current

You can get an automatic transfer switch. Its a box that has 2 AC inputs, so you can plug them into two different UPS's. Then you would have some UPS redundancy.

Ah, Automatic Transfer Switch :) Thats the wrd I was looking for.

How does it function?

two ac inputs, one fails, it switches to the other.