What wattage/VA UPS to get?

[rpeters83]

I have a small home server, nothing special, but it runs DNS, email, web, etc - it's just a PC running as a virtual host. It has 8 hard drives and 32GB of RAM with a AMD 6-core CPU.

I'm completely new to purchasing a UPS and am not sure how much power I need. According to Newegg's PSU calculator, I'm drawing not much more than 300 watts at peak (which it rarely ever sees). My hope is to have it at least run for 10 minutes if the power were to go out, as I'm not sure if I'll be around to cleanly shut it down.

I was looking at the CyberPower PFC units and am not sure what VA to purchase.

To try to get this running for maybe around 5-10 minutes, how much power do I need? Thanks.

 

[deees]

APC has tools for calculating runtime, (primarily for their units.)

By load:
http://www.apc.com/tools/ups_selector/US/en/home/load
By device:
http://www.apc.com/tools/ups_selector/US/en/home/device

You could use it to get a rough estimate. Just be sure to specify the home versions as the more expensive business class will typically have better power management and show longer run times per VA.

 

[rpeters83]

Thanks! Never saw this before. According to their numbers, with 350 watt max load (which it will never be at), it says even the 1000VA version should give me 10+ minutes on average.

Do you happen to know if this calculation of minutes is for full-load or average load?

Thanks.

 

[deees]

Do you happen to know if this calculation of minutes is for full-load or average load?

Thanks.

I think the runtime is based on a continuous load, (which would be both full and average.)

Check the graph on the product page: http://www.apc.com/resource/include/techspec_index.cfm?base_sku=BR1000G

If you asking if it considers peak load, (like during drive spin-up during boot), I don't think so. I know the device calculator, for network equipment is based purely on maximum PSU rating, not typical draw.

You'll always want to over-buy the UPS, because battery age, hardware upgrades, slow shutdown, etc., will short effect runtime.

Remember, if the UPS and server are set to autostart after power restoration, the server won't know about a second power outage until the UPS services load and can crash if the UPS battery is exhausted during the first shutdown.

 

[stormy1]

I would recommend a used 1500 apc smart ups with new batteries.
That would handle your current load and provide enough power for upgrades.
The nice thing about the sua1500 is that the fan only comes on when they are on battery.
In general the 1500 is as big as you can go on a home 15a circuit.

 

[michalrz]

You have 8 hard drives. Does the HDD controller do staggered spin-up?

Hard drives can pull some serious current as they are spinning up and that could trip overload on a weaker UPS unit even though the calculators say it should be fine.

Some critical features you might want to look out for:
- cold start - UPS can power up without mains AC
- true sine wave on battery backup - ensures stability especially with active PFC PSUs
- USB/RS232 port for automatic graceful shutdown
- auto-restart when mains AC returns
- buck/boost AVR
- line interactive type
- high efficiency / high power factor (as close to '1' as possible)