Right Sizing of UPS

[Javier_RA_apc]

Hi all,

I've been introduced with a really small installation where a SMX3000HV + APC9630 was installed.

Watching at the UPS status, I see that the max Output Watts has been 13%, and Output Efficiency is always 'load too low'.

There's an added issue with the space where the rack is installed, where the temperature represents an issue, there's no AC unit and the air flow does not seem to be enough, especially during the 'warm' months of summer!

I'm considering switching to a lower model, need to be short depth (again because of the rack location), so I was thinking of a SMX2200HVNC or a SMX1500RMI2UNC (BPUs are also much lower the smaller the model is).

Now the question:

SMX1500RMI2UNC output is 1.2KWatts
SMX3000HV output is 2.7KWatts
If my current 'Output Watts' is 13%, am I doing right these calculations?

Current output = 2,7*100/13 = 0,35KWatts
Output in 1500 = 0,35*100/1,2 = 29%
My 'Current Output' with SMX1500RMI2UNC will be aprox. 30%, which still leaves room for growth. And will be saving 2U and lots of BPUs (184 vs 133 BTU/h) 🙂

Looking forward to your comments, observations and corrections!

[voidstar_apc]

Calculations seem good. Just a note: load-too-low isn't an indicator of a problem; rather it's just why the UPS doesn't report efficiency. Getting the load up to 30% will help with detecting bad batteries during self-test and calibrating the runtime estimation during discharges. Make sure you're okay with reduced runtime (~35 minutes) or add batteries to compensate.

[Javier_RA_apc · Accepted solution]

On 9/9/2018 7:40 PM, voidstar said:

Make sure you're okay with reduced runtime (~35 minutes) or add batteries to compensate.

Most of the times 35 min should be fine, considering we don't expect working if there's a larger outage. Also adding external batteries would bring more BPUs, and one of the things I want to alleviate is the heat in the rack.

Thank you for your response!