Need Help selecting a UPS

[Caveman]

Would like to have one for an entire HT setup, but I'm really just worried about making sure my DLP Projector maintains power long enough for me to shut it down properly in a power outage.

Max output is 400W. I only need about 10 mins to shut it down (max). What does this translate into for VA rating?

I'd assume something as small as 500VA would be adequate?

 

[BladeVenom]

Watt output is typically around 60% of the VA rating. You could look up the power factor for the specific model you looking at if they don't give a watt rating. If you're using 400 watts max, you'll probably want something like 700VA or better.

Power Factor x VA = Watts

 

[Zepper]

Yup, the VA number should be about 50% more than the actual Watts number you're using. Newegg had the old model Kill A Watt meter on sale for $16. recently in the members' newsletter (if you aren't a member, let me know). Just plug everything you want to power into one power strip, then plug the strip into the KAW and the KAW into the wall. You'll then get the actual Watts you need. The AmpHours of the batteries in the UPS will tell you how much uptime you can expect. Most mfrs will provide a table for each model of UPS with the expected uptime for some different applied loads.

.bh.

PS: I just looked and the KAW deal ends tomorrow. It's in the "Guitar Hero" issue. .bh.

 

[Caveman]

Thanks. But it seems like "battery run time" will play a huge role here... I'm guessing the 50 and 60% figures tossed out are for 30 minutes shutdown margin??? I just need a few minutes... I think the PJ shuts down in 3 mins tops

 

[assemblage]

I have a Cyberpower CP1500AVRT.. My current computer, router, cable modem pulls 90 watts. The cyberpower control panel says it can run for 54 minutes. I'm pretty happy with it and for $100 at provantage it's a pretty good deal for a ups that size.

 

[BladeVenom]

VA has to do with power output, not how long it will run. If it's not powerful enough it won't run your PC at all.

Just check out these runtime charts:
http://www.apc.com/products/ru...ntime.cfm?upsfamily=21
http://www.apc.com/products/ru...ntime.cfm?upsfamily=23

 

[balane]

Personally, I think UPS 3rd Day Air is the best value if you can't wait for something to come via truck.

 

[Zepper]

Actually as said above, you have to have the right watts for your equipment or the UPS might fail to support your load at power outage time, the rule of thumb conversion from VA to Watts for reactive loads is to add 50% to the same number of VA. Say you get the KAW and it says your equip. is using 700W, so you'd need 700+350VA of UPS = 1050. Buy anything larger for longer uptime.

.bh.

 

[Navid]

Originally posted by: Caveman
Max output is 400W.

That figure is very important.
Are you sure you need that much power?

If you know the power (in Watts), that is all you need! Any decent UPS will give you the max. power it can deliver in addition to its VA rating in its specifications.

As an example, look at this UPS.
http://www.apc.com/resource/in...E750BB&total_watts=200
You can see that it specifies a max output power of 450W as well as a max VA rating of 750VA.

Get a UPS with a power (W) rating higher than the power you need.

The run time has nothing to do with either of those two figures. It has to do with the capacity of the battery it carries. You can find that out also from the spec.

 

[Zepper]

Well, it is not true that a higher rated UPS (in VA) has nothing to do with run time. Power that is not used directly can be spent over a longer time. IAC, normal consumer UPSes aren't offered with different optional batteries to give you the exact runtime you want at the power your application requires, so normally, you buy a higher rated UPS to get extra runtime.

And OP is going to be running a DLP projector bulb for a short while, I'm assuming he has to turn off the high wattage bulb and leave the fan running to cool things down for a while. As soon as the bulb goes out, the wattage needed will drop considerably. But IDK what your typical projector bulb needs for Wattage. The computer system's power needs will be fairly insignificant relative to that bulb.

.bh.

 

[seemingly random]

I recently purchased a CyberPower 1350. Finally got tired of the weekly power blips - they only last a second or two but enough to kill a running pc. Interestingly, these blips were not enough to kill a sleeping pc. The CyberPower runs silently unless on battery power - something that should be checked as the fan is pretty loud. It has worked out very well. I have three pc's, switches and routers on it - no monitors. I'm guessing it'll last about 10-15 minutes since it's advertised at 25 minutes with current wattage although haven't tested yet. One thing I'm still not used to though - when the relay pops to battery power, the noise scares the shit out of me.

I chose the CyberPower (in spite of its name) over an APC for price and the diagnostics display. I don't plan to hook it up to the pc via usb since the outages here are so short and don't need any more stuff running on the pc.

 

[Navid]

What I meant was that you can find two UPS units with identical VA ratings, but with different run times.


This is a unit with a 1500VA rating.
http://www.apc.com/resource/in...ex.cfm?base_sku=BR1500

Here, you can see the run time of this same unit with and without an additional battery pack.
http://www.apc.com/resource/in...ku=BR1500&family_id=23
You can see the different run times.

You can also see the same information, in more detail, here for BR1500 (no added battery) and BR1500+(1)BR24BP (added battery pack).
http://www.apc.com/products/ru...ntime.cfm?upsfamily=23


As I said, he can estimate the run time from the specs.

 

[seemingly random]

Originally posted by: Navid
Get a UPS with a power (W) rating higher than the power you need.

True. This is not like getting an overrated psu and wasting it.

The only reason I didn't go bigger is that I can always get another if more power is needed - eg. to run the monitors on battery, etc. I would go a lot bigger if I were running a TV, etc. Some models have the capability of adding another battery.

The 1350 I got is heavy for it's size - guessing about half that of a car battery.

There are some restrictions with UPS's - no printers, etc. - which didn't bother me.