SURT 10000 XLI Input Power Consumption under half load

[Anonymous user]

Hi,
I am not an expert at UPS's so this may be a basic question.
I am planning to purchase an online UPS (SURT10000UXI). My question is, if I load this only half, say 4000 Watts, how much will be input power consumption?
Will it still consume 10KW or 4KW?

I want to understand this because I have two sets of servers. One set which is always on and another which is periodically on/off. So I wanted to buy a single system with one set of batteries. However if it is going to consume too much power, I might need to consider some other alternative.

What do you recommend?

-Jack

[Anonymous user]

Great!
Thanks
Is there a APC document that describes the same thing.
I need to explain to my boss. 😉

-Jack

[BillP]

the unit will only draw as much power as you need as well as what the unit needs to operate. for instance, when the batteries are discharged, the UPS will consume power in order to charge them. this unit's battery charger is a max of 869 watts.

if you are using this UPS though, maybe not to it's full capacity, you will need to size the breaker properly per your local electrical code.

[Anonymous user]

Thanks for your reply.
Just to clearly understand.

If unit is loaded with say 4000 watts. Then if batteries are fully charged, it will consume roughly 4000 watts. If batteries are discharged to say 70% capacity, then unit will consume 4000+869 watts?

Did I get that right?

Thanks!
Jack

[BillP]

something like that. i would definitely agree that this is a "rough" calculation since there will most likely be some heat dissipation, efficiency to be factored in, etc

but i can definitely say that the unit will draw UP to 10kva and not constantly 10kva if you arent using that much with your load.

[BillP · Accepted solution]

hmm, nothing i could find that is public. some info from the user's guide on the rating might help and this excerpt I found below:

Internal Power Consumption is the amount of power coming into the UPS that does not leave to support the load, and is due to internal conversion to either heat or stored battery charge. Internal power consumption is equal to the inefficiency times the Watt rating at full load

Example: SURT5000XLI (full load) is rated at 3500 watts and 92% efficiency. The internal consumption is equal to 3500 watts * (100%-92%)=280 watts

As far as calculating the extra power consumption when the batteries are fully charging, you would add the charger watt rating to the internal power consumption. However, calling this internal power consumption may not be theoretically correct since the energy is being stored for later use, not dissipated and lost. There is a percentage of the charger energy that is also lost due to inefficiencies and secondary electro-chemical processes, but getting into this detail is not practical.

Battery charger for SURT5000XLI, 341 W

Total current drawn without load and with fully discharged batteries:

(280W+341W) / 230V (Mains Voltage) = 2,7A


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for SURT10000XLI:

-UPS efficiency on-line, on-battery, AC-AC (100% load) - 92%
-UPS efficiency DC-AC (inverter only) (100% load) - 96%
-UPS efficiency DC-AC (battery to output) (100% load) - 89%