recommend back up battery

[smalltime]

What would be the best backup battery power unit? I have 2 Koralia 1400's in my tank I would like to hook up to a batter backup. These pumps draw 6 watts a piece. So with a total of 12 watts which backup would keep circulation in the tank the longest?
Thanks

[EddieJ]

Make sure the unit is a true sine wave unit and not a stepped sine wave unit. Those Koralis's will rattle like no tomorrow on stepped sine wave. Just look thru the specs on whatever unit you are interested in.

[RokleM]

^^^

This. Unfortunately, they aren't cheap. As for what would last the longest, the answer would be the biggest you can get or a generator :D

APC Smart UPS is one of the units that has a true sine wave.
http://www.refurbups.com/Catalog/APC-Smart-UPS-Tower-Specials

[smalltime]

Heres the follow question, based off a units specs:
Output
Power Capacity 500 Watts / 750VA
Voltage 120V
Outlets (6) NEMA 5-15R
Input
Voltage 120V
Plug Type NEMA 5-15P
Cord Length 6 Feet
Est. Run Time
Half Load (250 Watts) 15.9 Minutes
Full Load (500 Watts) 4.6 Minutes

half load (250watts) 15.9 Minutes how long would 12 watts run approximently? Would it stay running until the battery is depleated?

[EddieJ]

that would give you about 3-4 hours runtime... and yes, it will run till the batteries are no longer able to provide voltage...