BATTERY BACKUPS ? HOW LONG WILL ONE LAST W/ JUST 2 POWER HEA

[Anonymous]

THE BATTERY BACK-UP, I THINK THEY ARE CALLED ARC OR SOMTHING LIKE THAT. WELL THE QUESTIO IS ON THE 150 DOLLAR MODEL, HOW LONG WILL IT LAST FOR 2 SM POWER HEADS IN THE TANK DURING A POWER OUTAGE?? IT SAYS IT WILL RUN A MONITOR AND COMPUTER FOR UP TO 15 MIN. DURING A OUTAGE. ANY THOUGHTS

 

[Anonymous]

Look at the capacity of the battery backup unit you are considering...it should be rated in Ampere-Hours, i.e., the number of amps drawn times the hours it will supply that much juice. Then, look at the pumps you want to back up and see how much current they draw (in amperes). Just divide the Amp-Hours available in the backup unit by the amps required by the equipment you want to run, and that will give you the hours it will back up.

The quick answer is, that the pumps draw a whole helluva lot less power than a CPU and Monitor, so you will probably get 6 or 8 hours out of a battery backup system designed for computers, assuming your are not trying to run your MH lighting!

 

[Anonymous]

ok -- my pump specs say this --

115 V 60 HZ 45 watts. how do i convert this to amp/hours? is it 45/110?

 

[Anonymous]

Yes...45/110 or .41 amps is a pretty close approximation...certainly far more accurate than you need. If you really want to get into the details of Apparent vs. Real Power and the calculations, go to
http://www.traceengineering.com/technical/tech_notes/tn11.html

One other thought, if you are getting a battery back-up, be sure to get one with enough capacity to handle your heater(s) as well...fine to keep the water circulating and oxygenated, but if they all freeze to death you've lost the war! <s>

Good luck.

ps. This is really taxing my pea-sized brain...I got a degree in electrical engineering 25 years ago, but have worked as a banker or consultant to bankers for the my entire career.

 

[Anonymous]

Hi,

Check out APC's website (www.apc.com) and check out the specs on the unit you want to buy. They have a rating for how long the unit will run with a certain powerload.

Mike/Donna, could you take the total wattage of the backup and powerheads and work it out that way? Do you need to find out the amperes to figure out how long it will run the equipment?

Thanks.

 

[Anonymous]

Sure...you can add up the wattage of all devices you want to put on the backup, divide by 110 to get the current they draw in amperes. Then, just decide how long you want to back-up for...say, 4 hours...and multiply that times the amperes you just calculated...battery backups are usually rated in ampere-hours (just like a car battery) since essentially all they are is a battery with a trickle charger. (and of course the circuitry to convert the DC to AC for running the backed up appliances.)