I have three APC BackUPS BR1500GI units and those units does not meet the advertised specs.

[BillP]

Hi all.

My APC BackUPS PRO BR1500GI 865W/1500VA is advertised to be able to handle a blackout with a load of 865W. Mine can't handle a blackout with a load of only 800W with a fresh new battery. I have three BR1500GI and both have this problem, so it isn't a problem of a particular unit. 

Every time I have a blackout while rendering and PCs where shutted down I come here to complain about it.
This happen only when the UPS is loaded with 800W, at 790W it can handle the load but those units are advertised to be able to handle 865W.

With the prices of this units, I was expecting a bit of over engineering and not sub engineering.

Obviously I completely lost my trust in APC and those are the last expensive APC units I buy.

[Brad_C]

On 18/3/2017 8:06 AM, Davide said:

This happen only when the UPS is loaded with 800W, at 790W it can handle the load but those units are advertised to be able to handle 865W.

No. Those units are rated to handle 1500VA *or* 865W at a maximum of 3:1 crest factor. If your load has a particularly bad power factor, or is at all misbehaved on the faux sine wave this UPS puts out, then the UPS may overload and shut down. Can you guarantee your load measurement is accurate, your power factor is accurate and your load characteristic is such that you can absolutely blame the UPS for being 75W under-rated when the load is being operated on a stepped sine wave?

On 18/3/2017 8:06 AM, Davide said:

I have three BR1500GI and both have this problem, so it isn't a problem of a particular unit. 

Sounds like you have an issue with what you have plugged into the unit then.

How have you actually measured your load characteristics, because on a stepped sine-wave output you need some pretty special gear to get an *accurate* measurement of load. A load that behaved on the mains sine might go completely of the wall when switched to a "modified sine".

[BillP]

I use two of the best Platinum PSU on the market, 2x Corsair AX860i and a Seasonic Prime 850W,
so yes, I have the best load a UPS can desider from a PC.

I have measured the load before switching to battery using a watt meter, the built in feature of the AX860i PSU and seeying the wattage reported from the BR1500GI it self.

[voidstar_apc]

One general issue is that PSUs can react to a power outage by trying to suck in more power to keep its bus capacitor filled up. As long as it doesn't exceed the rating (usually listed near the power plug) of the PSU, it's still within spec but not what you want if greater than what the UPS can provide. This happens within milliseconds.

My suggestion if you want to get to the bottom of this is to use light bulbs, hair driers, and other static resistive loads to reach the UPS watt limit. If the UPS fails this test, call tech support with the serial number to make sure it's not counterfeit and get a replacement if it truly doesn't meet spec.

[BillP]

On 3/19/2017 1:34 PM, voidstar said:

One general issue is that PSUs can react to a power outage by trying to suck in more power to keep its bus capacitor filled up. As long as it doesn't exceed the rating (usually listed near the power plug) of the PSU, it's still within spec but not what you want if greater than what the UPS can provide. This happens within milliseconds.

My suggestion if you want to get to the bottom of this is to use light bulbs, hair driers, and other static resistive loads to reach the UPS watt limit. If the UPS fails this test, call tech support with the serial number to make sure it's not counterfeit and get a replacement if it truly doesn't meet spec.

those UPSs are made to work with PC perihperals not with light bulbs.
I use the best in class PSU on the market, I expect to push them up to 865W.
Those expensive APCs should be over engineered a bit to handle a peak of some watt more.

A load of 800W is far less than the advertised 865W, I don't care if my PSU peak up to 900W,those expensive units should handle it.
What is the reason of spending 200, 300% more for an APC if they have similar behaviour?

[Brad_C]

On 20/3/2017 1:13 AM, Davide said:

I use two of the best Platinum PSU on the market, 2x Corsair AX860i and a Seasonic Prime 850W,
so yes, I have the best load a UPS can desider from a PC.

No, you have two nice PSUs that give clean power to your PC, but you have two of the worst possible PSUs for use on a non-sinewave UPS. Active PFC power supplies are potentially the worst possible kind of complex load to put on a non-sinewave UPS. The rapid changes of the incoming square wave do nasty things to the PFC controller causing it to draw power in dirty great gulps rather than "cleanly" as they do on a sine-wave input. Not something a UPS with a 3:1 crest factor is designed to cope with.

Do 10 seconds reading on Active PFC PSUs and non-sinewave UPS and you'll see the problem you have is A) extremely common, B) well documented and C) insurmountable. If you want to solve it, either significantly de-rate your UPS or buy a decent one with a real sine-wave output. The problem you are seeing manifests itself on *all* cheap non-sinewave UPS and is not specific to this particular model of APC.

A SmartUPS will do a sterling job for you. The cheaper BackUPS is not the right tool for this particular job.

Edit : Here's a nice quote from an old Seasonic FAQ (gone now I'm afraid).

Q: Will my new Seasonic PSU work with UPS? How powerful should be my UPS?

A: All Seasonic power supply units perfectly work with Online and Standby UPS and majority of Line-interactive UPS, providing up to 70~80% of their maximum Wattage. But some rare combinations of Seasonic power supplies and Line-interactive UPS might be working only at 50% of PSU’s max Wattage or be completely incompatible. The only way to be 100% sure is to check it with your UPS. As for the UPS Wattage, we recommend you to have it about 50~100% higher than your PSU Wattage.

Unfortunately if you expect your ~850W UPS to sustain a 900W load because (in your opinion) it was expensive, you are destined to go through life disappointed.

[BillP]

next time I will buy a cyberpower, atlantis or other similar brands that offer similar products at 1/3 of the price.

what is the sense of writing 865W on the specs, on the site and on the product if it can't handle it?
what is the reason of this number if it can't handle it?

Good PSUs for example are over engineered to handle pick power usage, if you buy a good 850W PSU, you can load it with 850W without any problems because they are overengineered for peak power usage.
Have you ever seen jonny guru loading 800W PSUs with 1000W and have no problem?

I'm really really disappointed from APC, the price of those things is around 500€ per unit.

500€ for what wattage?
should I get the calculator and input 865/2=432.5W?
is 432.5W the supported wattage? what is the supported wattage?

this is the last time I waste money on this crappy products sold as premium products.

[voidstar_apc · Accepted solution]

I can understand your frustration that your setup isn't working. Cyberpower has double conversion UPSes that might interest you at lower price points and power levels than APC's double conversion offerings. A double conversion topology has no transfer time and works under a wider range of input voltages.

If your BackUPS really doesn't handle the full 865W, you deserve to have it sorted out by APC tech support. This forum only offers advice. You can contact them here:

http://www.apc.com/us/en/support/contact-us/index.jsp

The reason you need to use light bulbs or hair dryers for testing and not your PSU is because your PSU can exceed the wattage of the UPS. For example, your AX860i PSU can supply up to 860W. Assuming peak efficiency (92%) it consumes at least 934W doing so. That is well above the 865W the UPS is rated for. And ironically, the more over-engineered your PSU, the more power it may consume.

The other reason is that during the period between a power failure and UPS intervention (called "transfer time", measured in milliseconds), PSUs sometimes try to draw their max power. Which, for your PSU, is at least 934W. You can test for this situation by turning the PC on while the UPS is already on battery and seeing if it works fine. Sometimes UPSes with a shorter transfer time, such as the SmartUPS' or any double conversion UPS, can improve this situation, although even then I'd recommend upping the UPS' wattage.

I can sympathize with wanting the BackUPS to handle loads well in excess of its stated spec. The BackUPS line is cost sensitive so while there are UPSes that can handle higher wattage, they're marked and priced as such.