Allan the principal difference between 24 and 48V is the batteries ability to supply the current under a heavy load without the voltage dipping too far, current is halved for 48V. If you are planning big loads or starting big loads ie air compressor large angle grinder well pump etc then 48V has advantages and 300A/h will cope with most everything.
I run my fruit packing shed on 24V, with two 3Kw inverters one is dedicated to the cool room in the summer for about 6-8 weeks the other runs the processing equipment and domestic requirements, the battery bank is large second hand batteries now 21 years old. If I did it again I would go 48V but I started with an old 32V Dunlight mill so went 24V
Generally the advice is to size your system to give 3 days autonomy without dropping below 50% charge, now that's all very well but one needs to be able to replace all this expended energy once the sun shines or wind blows again and this large battery bank is aging from day one. There is no one solution for all situations my personal preference is a bank that will see me through 2 days, I prefer to start the generator if necessary( you are probably going to have to anyway) I believe it is more cost effective than a huge battery bank aging daily used or not, my house bank is 1320 Ah 48 volt, adequate but I doubt it could sustain the full capacity of the inverter 6Kw/ 18Kw surge for long.
A large bank will, within your inverters capability allow you to run an AC occasionally but one still has to replace this expended energy, Ok battery power O/n run the generator during the day, we did that occasionally in the shed.
Basically with a large battery bank that does not go much below 10% discharge you will need 2Kw for every 1Kw the batteries absorb, this is a little variable, I have 4X24v banks of 660Ah batteries surviving at the packing shed, if load is needed and recharge is limited I reduce to 2-3 In service to aid the recharge, other wise I leave all 4 I/S as I have no charge regulation and 4 banks can absorb all incoming from solar and wind without the voltage going above 32V.
Will you be able to recharge a 3000Ah bank, yes, how efficiently depends on how much incoming you have, down Murry Bridge way wind should be a good option as you have stated others are surviving on wind. I believe solar is the backbone of a Re system my wind would be lucky to average 15% of my use from 3 mills but then there are days when it is more than enough even without the sun. Wind is like women most of the time there is not enough then there is too much.
Raps has closed in WA also I was not aware of that, I guess Ruddy spent all the dollars on ceiling insulation to electrocute tradies, but contact a dealer I strongly suspect it will restart when a new allocation of funds is made, July 1 is coming (election year). Our house system cost $75,000 of which the government paid half.
I have looked at your battery link, and can not comment I guess they are Chinese, cost is up there with the major brands, look at sites like Solar on line etc. Only you know what loads you will be running, have you lived off grid before? It's a struggle to economizes if there is a female in the house, if they are $#|+ty with you the first thing they do is use lots of power because they know you care about it. I still try but no too hard, I just start the generator or let the inverter start it, a few gallons of diesel is less confrontational and a tax deduction to boot.
I have PM'ed you me contact details.
allan
