Originally Posted by
lepete
Battery backup is designed for electrical devices to do graceful shutdown. It is not effective to sustain operation for any useful amount of time.
Let see:
Medium size tank (no light during power outage, no fuge, no sump):
250w heater
35W HOB skimmer
4x 20W Power Head
Total Wattage: 385W (let assume 450W)
APC UPS: 700 VA - 450W (info from APC tech spec)
Tank Runtime: 450W - about 9 min
1 PH Runtime: 20W - 3.4 hr
Cost: $80
APC UPS: 3000 VA - 2200 Watt
Spec Runtime: 2200- - 8.2 min
Tank Runtime: 450W - about 40 min
1 PH Runtime: 20W - 15 hr.
Cost: $550
Weight 142 lb, YES one hundred forty two pounds.
Summary:
If you were to run the above tank using the 700 VA UPS, you'll get 9 minutes of runtime. If you were just to run 1 powerhead, you'll get 3.4 hours. If you are to use the 3000 VA UPS, your tank equipments will run for 40 minutes. If you are just to run your powerhead using this UPS, you'll get 15 hr of runtime.
UPS is an option if you are just using it to oxygenate the water.
Caveat Emptor: If you just provide water movement, you tank temperature will plummet faster to that of room temperature.
This will run a powerhead and thermometer for around 6 hours. If in a pinch, I would put the PH on a timer to run for 3 minutes every ten minutes. In a real pinch, I would rip the baterries out of my golf cart.
Mc