Can you use the Back-UPS CS 500 with an extention cord?

[Anonymous user]

I have the Back-UPS CS 500. It has 3 battery protected outlets, and 3 surge only outlets. Currently, i have used only 2 battery protected outlets and i wanted to know how safe or productive it would be if i used an extension cord from the 3rd unused battery protected outlet about 20 feet or so, so that i can plug in my cable tv providers DVR. The DVR is, of course 120VAC, 80 Watts, 1.5 Amps, with a 120VAC outlet 5Amps, 24 Watts (if i did my math right?)

The DVR reports 120 VAC - 80 Watts
The dvr's builin outlet 120 VAC - 5 Amps.

Amps = Volts / Watts
Watts = Volts / Amps
Right?

Anyway, any insight would help. Thank you much!

[BillP · Accepted solution]

Hello, Spez.

It's generally not recommended to plug power strips or surge protectors ahead or behind the UPS. See this article for details:
http://nam-en.apc.com/cgi-bin/nam_en.cfg/php/enduser/std_adp.php?p_faqid=1372

However, for your plan to power your DVR, you would probably want to get a grounded extension cord (3 prong on both ends) to connect between that last battery outlet and your DVR. You can get nice indoor extension cords, typically called "banana" extensions at Home Depot or stores like that. They will have a 3 prong plug to go into the UPS, and maybe 3 grounded outlets on the other end in various lengths and colors. I own a few.

As long as you remember that the capacity of your Back-UPS is just 300 watts, and you only plug that DVR into this grounded extension cord, that would be an acceptable deployment.

Now for your calculations:

If the DVR is listed at 80 Watts, that's the peak power draw of the DVR. As long as you do not connect anything into the outlet on the back of the DVR, you only need to concern yourself with that 80W. I do not recommend using the built-in outlet on the DVR if you end up connecting the DVR to your Back-UPS. Anything you plug into that outlet will therefore be powered by the UPS and you'll likely overload the UPS, dropping your AV equipment suddenly.

Amps do not equal volts/watts.
Watts do not equal volts/amps.

Generally, if you have the watt rating of a given device, that's all you need to concern yourself with when discussing smaller UPS like yours. The power factor of a device like a DVR is very similar to that of your APC UPS.