Let's pull the trigger (offgrid)

Hi everyone, I have been here for a year, I was able to successfully install 2 280ah12v diy batteries with each BMS, 500w of solar, victron SCC, victron inverter and an Orion-TR to my sprinter van, and it is working absolutely well.

I hope I can document all very well here, so somebody could found it interesting and useful (like hundreds of posts I have been reviewing)

So, I need to buy a house, on the countryside (Europe, Catalonia) and just started to figure it out what size I would need for going totally offgrid (familly of 4, two newborns, so climate comfort is a must).

I don't have the actual Kw living consume (bc I need to move to another house, and these consume will be different). The average usage for a countryside house (including a big garage) is listed 30kw/day. Adding charging 1 EV (currently) and my wife next car is going to be another one with 100km (62 miles day per car).

Daily average consumption house (30kw/day)*
Daily charge EV1 (7,5kw/day)
Daily charge EV2 (7.5kw/day) maybe in 1-2 year time (but I want to make the numbers including it)
Total daily consumption (45kw/day)

Been using the Excel spreadsheet (awesome) by @FilterGuy and with big numbers.

I suppose I will need a 90kw battery pack for two days of storage (here we've 5.5 sun hours on winter, up to 7 during summer). Would be nice to have 3 days of backup (but 135kw battery seems a lot)... what do you think about it?

• 6 units => 304ah 48v lifepo4 with seplos or JK bms. (93,38kw - 1.824ah 48v)

Regarding of solar, for going from 0 to 100 % (in real time will be 10-90% soc) in one day (5.5 sun/hours), will need 18,2kwh (95,1kw/day).

If all that I'm assuming seems right for your point of view, the next move is to look for the inverter(s), regarding this, I see some options:

1. Different charge controllers and one inverter, seems expensive (like very expensive, maybe bc I was looking for victrons scc, with so low vdc imput in comparisson with some other AIOs). One option could be 2 units (Victron MPPT RS SmartSolar 450|200) and one inverter (the inverter has to be at least 12kw right? to use a phase 2 11,5kw EV charguer, so I could start with a Multiplus II 10kva and add another if is needed).
2. Different AIOs on parelel, as I'm in Europe (240 monophase, I guess you guys say single phase), for example the Growatt SPF 5000 (Strings of 10 units 455perc panels = 498volts, 114amps ISC, 4550w. So 4 strings of panels with one growatt each will be 456Amps, 18,2kwh.) or 3 of the new MPP solar 11kw (150amps each). With these installation, I think is going to have a big ilde consumption..)
3. Single AIO three-phase (380v) that it can handle up to 20kwh of solar, but then the house consumption is going to be unbalanced and I think that even that this system could be easier to install, will be expensive to balance for offgrid.

Thanks for reading, cheers!


* Maybe this 30kw/day average is going all electric, and I can make it lower (but heater/aircon pump is a must), also hot water could come from solar accumulator