Canadian TV, Computing and Home Theatre Forums banner

1 - 13 of 13 Posts

·
Registered
Joined
·
134 Posts
Discussion Starter #1
What size of a uniterruptable power supply should I get for a 630PVR? It will be the only device connected to the U.P.S. I'm not sure what to get. Thanks.
 

·
Registered
Joined
·
569 Posts
Two factors to consider;

1) Power consumption of the device

2) Median duration of power outages in your area.

If the power only goes out for momentary blips, then you don't need a large UPS. However, if you have to deal with longer outages, then you need to plan for a larger UPS.

If the DVR consumes 30W, then a 1000VA UPS will keep it going ~30mins, a 2000VA UPS will run for ~60mins etc. etc.

APC is one of the better UPS brands.
 

·
Registered
Joined
·
4,459 Posts
I had (still have, it just needs a battery), an APC BE-325 UPS. I used it for my older model Series 2 TiVo and a Motorola DSR315 receiver. It ran backup power for around 20 minutes, plenty of time to cleanly shut it down.
 

·
Super Moderator
Joined
·
56,505 Posts
If the DVR consumes 30W, then a 1000VA UPS will keep it going ~30mins, a 2000VA UPS will run for ~60mins etc.
Those run times are low. If all you've got connected to the battery side is the 630 at say 30W, then a 350 VA or 500 VA UPS should suffice. They can typically be found on sale for under $100. 750VA units are also typically quite inexpensive. Here's a calculator for determining the run time.

http://www.apc.com/tools/ups_selector/index.cfm

Click on US, then configure by load. For example, a 750 VA unit would last for about 160 minutes. 500 VA would therefore last for almost 2 hours. I have a very old APC 350VA UPS on my SA8300HD which consumes about 35W (eHDD and recording). It runs for about an hour on battery and I've got another couple of other small devices - cordless phone, cable amp plugged into the battery side.

Since this is applicable for all devices, not just Shaw Direct equipment, your thread will be moved to the appropriate forum.
 

·
Registered
Joined
·
7,131 Posts
It's best to rate UPS conservatively but a 1000VA USP is way over the top for a single DVR. A simple way to calculate the minimum size required is to multiply the total watts on the devices by four. (That's double to provide 50% head room and double again to get VA.) That usually provides about 10 minutes of run time. If more run time is required, refer to the run time chart for the UPS. Another consideration is that UPS are less efficient under light load so an oversized UPS will waste energy. Like 57 said, a 350VA or 500VA UPS will be fine for a single DVR. According to APC's run time chart, a CS350 or CS500 will provide about 50 minutes of run time at 50w. OTOH, an ES350 only provides about 15 minutes run time, an ES450 only provides about 25 minutes and an ES550 provides 60 minutes, so check the specs. (Costco has a couple of APC UPS for a good price.)
 

·
Registered
Joined
·
134 Posts
Discussion Starter #6
It's been said that unplugging a Shaw Direct 630PVR is hard on it, so a power failure would be the same thing. My wanting a UPS is to provide power to the unit while it is turned off. Power failures can be 2 hours where I live. Anyone know how much power the unit draws while it's turned off? I looked in the manual and didn't see any power consumption specs.
 

·
Super Moderator
Joined
·
56,505 Posts
The only way to know for sure would be to get a Watt Meter. Any single specs on the unit itself or in the manual would likely be "max" draw.

http://www.digitalhome.ca/forum/showthread.php?t=35430&highlight=parasitic

I would guess it's about 20-30 Watts in standby, therefore a 500 VA UPS should suffice, giving you a couple of hours. If you want more cushion, just buy a 750, which would give you almost 3 hours.
 

·
Registered
Joined
·
80 Posts
I got the 400 watt NOMA backup at can tire and have my whole home theater plugged in. I was watching a show on the pvr when the power went out and continued watching (Shaw Direct 630, Sharp 46" lcd, and Sony 5.1 receiver) for 40 min's then powered down tv and surround so PVR could record any upcoming shows on remaining battery power.
 

·
Registered
Joined
·
1,906 Posts
The only way to know for sure would be to get a Watt Meter. Any single specs on the unit itself or in the manual would likely be "max" draw.

http://www.digitalhome.ca/forum/showthread.php?t=35430&highlight=parasitic

I would guess it's about 20-30 Watts in standby, therefore a 500 VA UPS should suffice, giving you a couple of hours. If you want more cushion, just buy a 750, which would give you almost 3 hours.
Tell me why that wouldn't be at least 7-8 hours on standy with 500VA??

\VA isn't exactly watts but isn't it about 1/2?? 250-40 = 6 hours.
 

·
Super Moderator
Joined
·
56,505 Posts
gzink The UPS are rated by VA and you're correct that you shouldn't connect more than about 1/2 the VA rating in terms of total Watts plugged into the battery side, otherwise the draw will be too much for the battery and the UPS will simply shut down.

However, Watts doesn't equal Watt-hours, which is the factor you're missing. The calculator that I provided in post 4 allows you to get an estimate of the time, based on the Watts connected.

a1canuck That's a helluva UPS if it kept all that going for 40 minutes without shutting down and then continued to record... I always recommend that people don't plug their TVs or AVRs into the battery side of a UPS since that could draw enough power to simply shut the UPS down making it ineffective at keeping the PVR powered. Was it a 400 Watt or 400 VA UPS? The max you should plug into a 400VA UPS would be about 200W on the battery side, but if it was 400W, that may explain why you got away with it.
 

·
Registered
Joined
·
751 Posts
I always recommend that people don't plug their TVs or AVRs into the battery side of a UPS [...]
I bought a 700VA UPS specifically for the purpose of plugging my TV into it. This was because it was a rear-projection DLP TV. The TV had a fan to cool the bulb, that continued to run for about a minute after the TV was powered off. This was to prevent "heat soak" from damaging the bulb. If the power failed, this cooling fan wouldn't run, possibly lessening the life of the bulb. Since I only have my TV on when I'm present and watching, the UPS allowed me to turn off the TV during a persistent power failure and still have the cooling fan run for its normal duration.

I now have an LED based DLP TV and no fans run after the TV is shut off, so the UPS doesn't serve its original primary purpose. I still have the TV plugged into it, as well as my PVR, so my viewing isn't interrupted during short power failures. However, the new primary purpose of the UPS is (as is the topic of this thread) to help prevent loosing PVR recordings.
 

·
Registered
Joined
·
7,131 Posts
The other thing that people are overlooking is that all UPS units have overhead power consumed in operation plus losses due to inefficiency. Many consumer grade UPS units will only run for 45 minutes maximum, with no load. Run time goes down from there under load. Some newly designed units are more energy efficient but expecting much more than 60 minutes from a consumer grade device is not realistic. Larger UPS units consume more energy in normal operation and are designed to backup higher loads, not provide infinitely extended run times. If extended run times are a necessity, get a network/server grade UPS that offers larger internal batteries and external battery connections for extended run times (quite expensive) or get a whole home backup generator (very expensive but worthwhile where power is very unreliable.)

Watts doesn't equal Watt-hours, which is the factor you're missing.
Correct. Run time is determined by the voltage and amp-hour rating of the battery. That is further reduced by UPS inefficiency and the power factor of the load. A typical consumer grade UPS battery provides between 7 and 25 amp-hours at 12v.
 
1 - 13 of 13 Posts
Top