Super deals on the SI6048's. Jump on those if you want to go that route.
That said, an alternative option would be Victron units. The Multiplus II 5K specifically. They do require adding a split-phase transformer externally but if you get them from an installer/dealer such as myself or someone else, you could be looking at a cutting-edge system akin to SMA for decent price. Just 2 would be a surge capacity of 18KW. 3 would be 27KW. Would easily start your HVAC.
The MultiPlus-II is ideally suited for professional marine, yachting, vehicle and land based off-grid applications. Learn more now.
www.victronenergy.com
If you went Victron you can also DC+AC couple. Having the advantages of both worlds while still have the entire system on a single controller.
You could also consider DEYE. Thier units are essentially identical to SOL-ARK. It's been debated but IMHO they are the OEM for SOL-ARK. Simply too many factors point to that. You can get the 7.6KW model for under $2K, making 2 of them less than $4K before shipping. 3 of them however would give you a max PV input of ~29KW.
The trick though is buying them from China directly. Some hoops to jump through there as DEYE is not officially allowed contract-wise to sell to the USA directly. More on that in other parts of the forum.
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www.deyeinverter.com
at the link provided the specs are all pretty favorable except one they appear to be european single phase 230v output otherwise 2 of them would suit me pretty well but I also need 240 split phase grid input. If I was totally off grid this would be ok if I got a european model generator or conversion etc.