Power Consumption when UPS is in charging mode

[Anonymous user]

I have a 800VA APC UPS. I feel that the UPS consumes higher power when charging. I have not checked this by any meter or so, but going by my electricity bill it looks so. Has anyone checked this?

[Anonymous user · Accepted solution]

Hi,

I'm about to buy APC Back UPS RS LCD 550 Master Control BR550GI, but before that I need to ensure, that my power socket will handle the UPS.

Can you please tell me what is the maximum power consumption for this UPS in the most loaded mode (I'm guessing that's when the batteries are completely discharged and the re-charging process just started)?

My main power network is 230V AC.

Thank you very much!

Regards,

Nick

[BillP · Accepted solution]

This unit is limited to 6-7 amps. It only has a 5W battery charger too.

[Anonymous user · Accepted solution]

Hi Angela,

Thank you very much for your response. It is really helpful. I noticed, that the fuse is 7 Amp and the max input current is set to 6 Amps, but I didn't know the charger wattage. That's very usefult.

As a suggestion to APC team, it will be very useful if you include into the specification sheet the charger wattage.

Thank you for your time!

Regards,

Nick

[BillP · Accepted solution]

Hi Angela,

I would like to know if I have attached a battery pack to the UPS. Is there any different on the Internal power consumption of the UPS? As I know there is 1 battery on the UPS and 2 batteries on the battery pack (refer to my model below). Is the battery charged one by one or all 3 at the same time?

UPS	APC Smart-UPS XL 3000VA RM 3U 230V
Battery Pack for UPS	APC Smart-UPS XL 48V RM 3U Battery Pack

Thanks.

Best Rgds,
Ricky Lee

[BillP · Accepted solution]

Hi,

The UPS will not use more power but it will take longer to charge. More batteries connected does not affect the UPS charger power that would be used whether no battery packs or extra battery packs. The UPS also charges all of the batteries in parallel and treats the UPS and external battery pack batteries as one giant 48V string since they are part of the same bus.

[Anonymous user]

I have a 800VA APC UPS. I feel that the UPS consumes higher power when charging. I have not checked this by any meter or so, but going by my electricity bill it looks so. Has anyone checked this?

[Techie_apc · Accepted solution]

Ramesh, Could you please let us know the exact model number of the UPS? There are many models available in 800 VA range. Each model consume power in different manner. I would appreciate if you can provide us the exact model number. You can find it on a white bar code sticker at the rear/bottom of the UPS.

[Anonymous user · Accepted solution]

Hi
The model of my UPS is HI800SQ

[Techie_apc · Accepted solution]

If the HI800SQ is connected to the 80 AH battery, the unit will consume 8 Amps of current to charge the completely discharged battery. If the battery is charged fully by the unit, then the unit will consume minimal power.

Please remember that the unit charges its battery in order to provide power in the event of power failure to the connected equipment. The Battery Charging Power is delivered to the Connected equipment when there is no power from the wall. So it is equivalent to the power consumption which is drawn by the connected equipment when there is power from the wall. I hope that this makes sense to determine why the electricity bill usage is high after using the HI800SQ.

[Anonymous user · Accepted solution]

What about the APC Smart-UPS 1500VA USB & Serial RM 2U 120V model? I see that it says, on the back panel, 12A max. input. If charging completely discharged battery with a full load, will it draw that much current?

[BillP]

Hi Shawn, welcome to the APC Forum.

I would do the best that I can to answer your question but first can you provide the exact model number of your UPS? This can be found at the back of your unit, it is a small white barcoded sticker.

[BillP · Accepted solution]

Thanks Shawn, here is what I was able to get for you.

UPS Details:
SUA1500RM2U
VA Capacity = 1440 VA
Watt Capacity = 980 Watts
Battery Charger Power = 144 Watts
Efficiency at Full Load = 95%

Total Current Draw without load and completely discharged batteries =1.608A

[Anonymous user · Accepted solution]

Hi
Our UPS model is SUA750XLI. Is anyone could tell us the power consumption for this model?

Thanks in advance
Kai

[Anonymous user · Accepted solution]

Hello

Please, tell me power consumption in charging mode for following models:

1. SUA3000RMXLI3U

2. SUA3000RMXLI3U with 1x SUA48RMXLBP3U

3. SUA5000RMI5U

Thanks

Dmitry

[BillP]

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.

For your UPSs, SUA3000RMXLI3U has a 287W charger and SUA5000RMI5U has a 542 watt charger. You'll just need to look up the efficiency for your UPS listed on apc.com:

http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SUA3000RMXLI3U

http://www.apc.com/resource/include/techspec_index.cfm?base_sku=SUA5000RMI5U

[Anonymous user]

A secondary spec which can be used as a "base value" to calculate internal consumption is the published "Online Thermal Dissipation" value in the Environmental specs. Online thermal dissipation should mirror how much real power (watts) is being consumed by the ups which is converted directly to heat:

To take Angela's example for the SUA5000RMI5U the thermal dissipation spec is 430 BTU/hr. If you take that figure and multiply by .000283 (to convert BTU/hr to Kilowatts) that gives you a value of around 125 watts. Based on the "Electrical" spec of 96% efficiency, the SUA5000 @ 4000 Watts/5000VA would consume about 150 to 160 watts by itself at full load. I believe the difference (about 20 - 25 watts) is made up by electrical energy converted to mechanical to spin the fans.

Its clear that this spec is only concerned with the UPS batteries being at proper float voltage, so one can then take the battery charging circuit wattage rating and add it to this Thermal Dissipation spec conversion to get the maximum power that would ever be consumed by the UPS itself.

[Anonymous user · Accepted solution]

Here's the scenario I would like to have someone test:

Start with a fully-charged UPS with no load.  Use a Kill-A-Watt type device

to measure the accumulated number of kwh used during a month (or week)

of operation when no power outages occur.

After all, many of us go many months without any power outage.

So the results of this test would represent the typical operating

cost of a UPS.  I'd like to see the results for the Back-UPS Pro 1000, 1300 and 1500.

I'm guessing some of you have already done this test.