Outbackozzie wrote:
I have to dissagree with the battery backup being too expensive.
I have posted many times in the past my backup system, but here it goes again.
1 x 300w inverter = $80
1 x 200AH Battery = $250
1 x Battery charger to suit what you draw from the battery = $25 - $100.
Very easy to put together, and most inverters have a low battery alarm (even cheapy dick smiths) that is very loud.
I dont see this as being cost prohibitive, compared to loosing your fish.
A 65w 4500lph pump draws ~5A @ 12V DC. A very large AP system could be run from 300w inverter, using low head, high flow pumps, like the Tornado's.
There are so many variables here, I was looking at running a 240 volt system as it was designed and existed for my comments above, not actually in a hospital sort of mode
Ok heres the calcs
if we have a 200 ah battery that is 12 volts - lets say we have 2400 watts
Inverter efficiency - some are 95% average 90%
Inverter drop out voltage - 10.5 volts
Total power * inv eff = 2400*.90 = 2160 watts (if running 12 volt pumps then this isnt taken into account)
If we running a basic 250 watt pump and thats all in the system a basic flood and drain back into main FT, then this without taking inefficiencies into the system would be approx 20 A 12 volts from the battery, this puts us on a 10 hour discharge curve, u should get 10 hours run time for this pump before the inverter 10.5 volts is reached, start to add more pumps and air generation supplies like a lot of systems I see here and u loose currant at a higher rate as you would expect also u loose total battery storage capacity due to the physics of the battery, so the loss are sort of 2 fold, now if it is running on a cycle on off on off then this has to be built in as well and will depending on the battery selected will give u longer life. I wont go into DOD of batteries as I imaging ur talking Deep Cycle batteries
So yes If u have a hospital system setup or a minimal current drain system then battery backup is an option but if u have a large outage like we get from time to time 12 to 24 hours then more batteries and bigger inverters or a generator
Anyway food for thought for those thinking of a backup system, mind u im still trying to get mine up and running lol
Bree