Andy,
I tend to agree with you re using gridtie, so much less fuss.
Re the air conditioning, I put a watt metre on my old, 18years, aircon and was amazed at how low it actually took in the heat of summer, it took about 1.2 kilowatt for the first 15 mins and then dropped to about 800 watts. So I expect my new mitsibuti inverter air con to take less than that.
The only good thing about west facing panels is they give a lot of power when most needed in the afternoons and early night time. I will put 1.8 kws of panels on the west roof which should run an aircon and put some charge back into the battery.
I was told when I got my Ibredrola quote for grid tie for 5600euros, for 3.6kws, that I should get nearly some 1600 euros as an eu rebate. Did you recieve any rebate, it can take 18 months.?
I would hope I too could claim rebate on batteries and the equipment, but as you know paperwork and technicalities can be difficult in Spain.
As an aside, I have an 1000watt, 48v ebike and cycle some 60kms on a charge and an amazed how good lithium batteries are. Ive done nearly 2500 kms in the 18 months Ive had the battery. So I have confidence in lit. batteries.
I have sourced a supply of batteries from china, Docan, Jenny Wu, who comes well recommended on Utube. 8 cells, 3.7volts at 230ah and 8 in series give you 24v at some 5.8kw, but you also need a BMS, battery management system at 120euros and the total cost would be 1100 euros.
Yes, I know, gridtie is less fuss and not much more expensive., especially if grants are guaranteed
Thanks for your thoughts.
Tony