I have a 5.5 Kw system with 2 outback grid tie inverters, 2 outback 80 amp charge controllers and 4 51v 120Ah lithium batteries. I have less than 7000.00 in this system. One of the ways I kept cost down was buying used or refurbished as much as I could.
Most of my panels came from San Tan Solar
https://www.santansolar.com/product-category/solar-panels/?_wcf_search=solarpanels%3D352%252C117%252C355 - my total panel cost was less than 1500.00 but I picked them up rather than pay shipping which would have been another 500 or so.
My inverters are Older GTX (circa 2010) refurbished,they are not quite as efficient as new ones but at the price of those solar panels it is easy enough to get a couple of extra to offset this if you need too. - Outback claims these will not charge lithium batteries but that's not really true, its all about what you set the voltages too and that the batteries have good BMS units. Refurbished 2 units cost 1200.00
2 -20 amp hour charge controllers. These I did buy new at cost of 800.00 from Amazon
4 - 51v 120 ah lithium batteries. Used out of CA they cost me 1200.00 for all with a grantee they would hold at least 95% of rated power. Have been using them for over 2 years with no problems.
1 - flex mate monitor 300.00 makes it alot easier to setup and monitor everything.
Miss wire, connectors, fuses/breakers, etc. 650.00
Mounting frames and hardware 1000.00
I called an installer not too long ago to see what a system like this would cost - was quoted almost 60,000.00
I guess my point to all this is it is possible to build a robust system that will easy run a home and not break the bank doing it.
