# APC UPS battery recharge time question

My UPS requirements are 2 Fans and 2 Energy Savers with 1 ptcl router. With 100 watts each for the fans and 25 watts each for energy savers, this is 250 watts load with another 25 watts(? not sure) for the router. So, I am hoping that a 650 VA/400 Watts UPS should cover me for the above load, right?

Accordingly I am interested in APC Back-UPS, 400 Watts / 650 VA. However, the RBC17 battery that comes with this has 108 volts-amps-hours. This volts-amps-hours value seems to be tiny. I am guessing that if it is 12 volt then the AH value would be 9? However, they list the recharge-time for this battery as 8 hours?!

So, my questions are

1. Why does it take so much recharge time for such a small capacity battery?

2. I am thinking of using this with the above setup with around 6 hours of load shedding. Will a much larger battery than the built-in one, around 120 AH work/suffice for my setup and load-shedding? What about the recharge time in my case?

Thanks a lot for your time!

Welcome to WP forums

When calculating the power requirements for AC loads, always calculate VA rating rather than watts. So a fan rated at 80W will consume 80W/0.6 = 133 VA (0.6 is the power factor for typical inductive load, you actually need to measure it but for simplicity we assume fans to have 0.6 power factor)

Same is the case with energy saver lamps. Typical power factor is 0.45-0.50, so 25W/0.45 = 55VA, adding all of your loads,

2 x fans @ 133VA = 266 VA

2 x lights @55VA = 110VA

1 x router @ 15VA = 15VA

Total = 391 VA , thereby meaning your UPS selection is OK, you will be loading your UPS 391/650 = 60 % approximately.

You are right, 108 Volt-Ampere-Hour is actually 9AH at 12V, this is sealed lead acid battery.

1) The safe and recommended charging rate for a sealed lead acid battery is 10% of its rated capacity meaning that you should charge it at not more than 0.9A which will take approximately 10 hours to fully charge it.

2) If you want to use this UPS for 6 hours backup, a much larger battery will do but the built-in charger is not sufficient to charge this large external battery. You will need to use an external charger with this setup.

I hope this answers your queries. Keep in mind that a UPS is not meant for load shedding, they are designed to protect your equipment/ data / hours of work should anything bad happen with electric supply mains.

Thanks a lot for the detailed and insightful answer.

I know UPS is not supposed to be used for load-shedding but what can one do? I have been using a local made UPS with a Volta battery and there were no ends of troubles with it.

That is why I am thinking of getting this APC one as it is within my range and I am hoping to get a Haze battery along with it.

So, regarding the external charger, could you let me know the name of a good one for a 12 volt 120 AH "sealed lead acid" battery?

Thanks

[quote=", post:, topic:"]

I have been using a local made UPS with a Volta battery and there were no ends of troubles with it.
[/quote]

LOL - Desi UPS are designed with the criteria “If it works, its OK to market this product”

[quote=", post:, topic:"]
So, regarding the external charger, could you let me know the name of a good one for a 12 volt 120 AH “sealed lead acid” battery?
[/quote]

To adequately charge 120AH battery, you need at least 12A charger. Unfortunately I don’t know of any place where you can get a quality charger at a reasonable price, I had imported some SMPS type power supplies 12V/10A which I had used with many UPS. I will see if I have some in stock or not.

BTW: Do you have 6 hours continuous load shedding or 6 hours scattered around 24 hours ?

Any idea where i can get a APC Smart-UPS 1500VA in Karachi and how much it will cost me?

[quote=“Frost, post:5, topic:14520”]

Any idea where i can get a APC Smart-UPS 1500VA in Karachi and how much it will cost me?

[/quote]

it ll cost you atleast 16k for the UPS and there are some dealers on PG selling them in whole sale…

Thanks

@ali79.. check you pm

APC Smart-UPS 1500VA (model: SUA1500I) is available

contact me for APC, MG and other imported UPS (new & used)

You don't need an external charger as you can access the control panel of the UPS by downloading its software and installing it on your pc as once you have accessed the control panel you can enable fast charging

[quote=“wildlaurel, post:7, topic:14520”]

@ali79… check you pm

APC Smart-UPS 1500VA (model: SUA1500I) is available

contact me for APC, MG and other imported UPS (new & used)

[/quote]

Can you mention the price for used and new? (SUA1500I) and can you mention the kind of configuration we’ve to setup with this ups? is there a battery inside it?

Regards

You should be able to get a used unit for 15k or less.. in winters you might get it at a cheaper rate as its peak season at the moment. The new unit is for 49k as per the rates mentioned on galaxy.com.pk for SUA1500I

Well yes there is a battery inside it but they are sold separately by the dealers as regards the used units. In new ones they are present hence the high price.

Well you don't need any special configuration a diagram has been present in this link by a fellow member Ijaz to whom i am very thankful for providing it.