Smart UPS 750VA vs Cyberpower 600VA

[BillP]

I've got a small home setup with a Qnap NAS, some networking hardware and external hard drive all setup and connected to a UPS. The power supply in my area is pretty stable, but I probably get a brief outage once every month or two, plus the occasional storm blackout. Surges have been an issue on occasion. 

For the past several years, I've been using a Cyberpower 600VA, which was cheap, and for the money, performed it's job admirably. 

https://www.cyberpower.com/au/en/product/sku/Value600EI 

It's probably more than 3 years old now though, so I while it's definitely working fine at the moment I would expect the battery to be on it's last year or two. 

I recently picked up a second hand Smart-UPS 750VA, which despite being at least 8 years old, externally looked in very good condition. (You may know the age better than me!) An inspection of the device indicated nothing that looked out of order, other than some very much dead batteries. I've replaced these, and it seems to work perfectly. I can't get PowerChute to install on my laptop to perform full diagnostics, but plugging the device into my NAS shows it's detected correctly and reports status ok. 

http://www.apc.com/shop/ng/en/products/APC-Smart-UPS-750VA-USB-Serial-230V/P-SUA750I

My question is this:

Should I replace my (smaller/cheaper/newer) Cyberpower UPS with the (bigger/older) APC Smart UPS? The APC device was a lot more expensive when purchased, and will offer substantially greater run time, but I'm more concerned with future reliability, and the longevity of my NAS so the quality of the power it's supplied. Does the APC offer a noticeably cleaner power supply in some way?

Thanks!

[BillP]

Hello David,

After reviewing the specifications of the CyberPower UPS, I would say that replacing it with the APC would be the better option. Although the APC unit is older, it will provide more run time, can support a larger load, has a higher surge rating, and has a user replaceable battery. Based off of the product page, it appears that the CyberPower unit does not have a replaceable battery, this means in about a year or two when the battery does go bad, the whole unit will need to be replaced. As for the power output, the APC unit will provide cleaner power. The APC unit provides a pure sine wave whereas the CyberPower gives a simulated (step-approximated) sine wave.

Regards,

[BillP]

Thanks for the suggestion William. I suspect you're probably right, but I was on the lookout for people saying don't touch a UPS over X years old because Y will be unreliable, or killer feature Z is not going to be included in that model!

More questions while I have an audience... 

Other than the batteries themselves, is their anything else to look out for when servicing a UPS?

I've noticed that the device gets a bit warmer when idling than the little Cyberpower. Is a little warmth normal when idle?

Finally, is the idle power consumption of the UPS itself something that I'm missing in the specifications, or would I need to try to measure it myself?

[voidstar_apc]

On 3/27/2017 10:06 AM, David said:

Thanks for the suggestion William. I suspect you're probably right, but I was on the lookout for people saying don't touch a UPS over X years old because Y will be unreliable, or killer feature Z is not going to be included in that model!

General rule of thumb is electronics are designed to last ~10 years. Many UPSes last well beyond that, and some do not. The lead-acid batteries inside the UPS last 3-5 years with normal use so a UPS without replaceable batteries has a built-in expiration date.

Newer SmartUPS units are lighter, can be a little more efficient, and have a fancy LCD display. The older ones have a heavy transformer inside that helps make them quite robust. So feature-wise, I wouldn't mind using an older SmartUPS.

On 3/27/2017 10:06 AM, David said:

Other than the batteries themselves, is their anything else to look out for when servicing a UPS?

Only the battery is user-serviceable. In terms of component failure, I'd expect fans (if present) to fail first followed by relays and electrolytic capacitors. The surge protection (MOVs) are consumable based on the surges they absorb.

On 3/27/2017 10:06 AM, David said:

I've noticed that the device gets a bit warmer when idling than the little Cyberpower. Is a little warmth normal when idle?

I wouldn't worry about it.

On 3/27/2017 10:06 AM, David said:

Finally, is the idle power consumption of the UPS itself something that I'm missing in the specifications, or would I need to try to measure it myself?

Power consumed by the UPS can be derived from the efficiency graph (in the "tech specs" tab of this apc.com page😞

Power consumption = Watts out * (1/efficiency - 1)

At 25% load it is 89.4% efficient so: 0.25 * 500W * (1/0.894 - 1) = 14W

At 100% load it is 96.3% efficient so: 500W * (1/0.963 - 1) = 19W

Hope that helps.

[BillP · Accepted solution]

Thanks for the advice. All questions answered!

I'll swap over to the Smart UPS and see how it goes.