WannaB,
You wrote:
"I know the pump is 1/2 horse, 230/115v, max amp. is 10.8/5.4."
I think you mean 230/110V, 5.4/10.8A.
If you need to run it at a given rate, 3 gal minute, plus keep a light bulb warming the joint up so everything doesn't freeze it must be a cold SOB where you are. Do you have to supply that much water for the stock? I think with a flow through the pump and the heated room you're gonna be safe from freezeup unless you're on the North Slope.
Multiplying 110VX10.8A=1188 wats. So if powered by batteries through an inverter you'll need one maybe 3 times the running AC demand of the pump upon startup. The motor will pull a great deal more than the nameplate for the first few moments it starts. So avoid start-stop cycles. So to run the pump alone you will need a 3000/6000 watt inverter as you say, and maybe one even higher rated. I'd ask the inverter maker.
The batteries, at least lead acid, will chill and lose effectiveness if exposed to that kind of cold. If possible, even if you're gonna switch them, house them in the well house. As for the amp hour rating and voltage of the battery bank it's your call. Switch them out often with a small bank, but to run that pump any time at all is gonna require a pretty beffy battery bank. You'll need a pair of trailers to make them big enough to last 48-72 hours.
- V X 99 A = 1188 watts.
- V X 49.5 A = 1188 watts.
- V X 24.75A = 1188 watts
That's IF the batteries are perfect, IF the inverter is perfect, IF the wiring is perfect, yadda yadda. Drawing 100 amps from a 12V bank is possible, but you'd have to make said bank huge to have it last more than a few hours under that sort of load. Going to 48 volts will just force you to have more batteries to get the higher voltage. Higher voltages require less thick cabling. Nothing's perfect so prepare for loses and plan accordingly. There are AC inverters for each of these voltages DC source.
Did you ever consider a very small diesel engine housed with the pump to power it as needed and to lend it's heat to the area?. I have a Kubota® one cylinder engine that is water cooled. Between the exhaust and radiated heat the BTU's are up there. Mine uses about 4-5 OUNCES per hour of diesel pulling a large frame alernator. It could, and will, drive an AC generator head as well. Pepa (a poster to this forum) has a much better setup and he's running veggie diesel in a Lister-Petter®. Both of us are running surplus used US armed forces engines. I can't speak for Pepa, but I'm pretty proud of my $250 engine (new about $1500). These deals are still out there, if you look. You could also run a line from an engine to the stock tank and back to keep it from freezing, and maybe just a pump would do that, but with a hot water line one could be sure.
Solar? I say one can never have too many panels, nor too many batteries. My 750 watt array is great. I plan on adding to it until I have 1.5KW. I have a 1320AH 12V bank of 6V golf cart batteries I wish was double. I wouldn't even try to run a load like your pump without my engine adding amps to the bank. That's what I have to do whe I run the AC here in the summer. I don't need my engine's heat then!!!!!!
Feedback, please, WannaB.