In it's location the solar is very effective, the 4kw is the actual generation rather than a label rating. 100% full sun, no shade, no clouds. The array typically generates over 20kw per day. The house is pretty efficient and the weather is very nice both summer and winter. This is not an area with a harsh winter or summer.

Shade and clouds of any kind, even very minor, have a HUGE effect on the production of a solar array.

I don't know about 43kWH/5400$. But, here's the system I've been looking at:

https://www.expertpower.us/products/10800w-50kwh?_pos=2&_sid...

That's 50KWH of battery, plus the 10.8KW of solar, inverters, etc., all for $17K. That system is microgrid (not grid following) capable; so, you can run it during a blackout. The switchover is pretty good, too, so you don't need a second backup system.

Ya, the OP is not telling the truth. One there isn't a "variety", second they aren't UL listed at that price. I've spent months researching this space for an off grid setup and these are the two best setups direct from China from a cost standpoint for 15 kWh. Neither are UL listed:

https://www.apexiummall.com/index.php?route=product/product&...

https://yixiangpower.com/products/yixiang-vertical-15kw-diy-...

Both would cost roughly $4800~$5500 for that total size.

If you want good customer service, dependable, UL listed, and correctly priced, then this is the king: https://signaturesolar.com/eg4-wallmount-indoor-battery-48v-...

UL listed ~45 kWh will cost you $10k, not $5.4k.

It would be multiple batteries totaling that. Stock and prices are constantly changing but RUiXU, EG4 and EcoWorthy are widely available brands with UL listed options. Will Prowse's website has a page dedicated to code compliant batteries and there are several long lists and excel sheets on the diysolarforum.

I don't believe they are UL certified, but Dumfume sells 3.6kwh (300ah-12v) lifepo4 batteries for $320. 15 of those would get you 54kwh for <$5k. Might be tough to be anywhere near that point for UL certified only, though.

I did not name specifics because things are constantly changing in this market and these threads tend to live for years. Stock and prices are constantly changing but RUiXU, EG4 and EcoWorthy are widely available brands with UL listed options. Will Prowse's website has a page dedicated to code compliant batteries and there are several long lists and excel sheets on the diysolarforum.

That is a much more complex topic driven by the regulations where you live. Where my house is, there is more or less no regulation and you can do as you please. In a purely technical sense there is not a lot of knowhow beyond basic electrical understanding, to setup these systems. Physically speaking these 280ah or larger battery setups are VERY heavy, hundreds of pounds per unit.

People seem to get really mad and accusatory over these sorts of things which is why I hate posting brands and such. The information changes very frequently as to what the "best" offer is. The diysolarforum is a very good resource to find the latest information.

This area has few days over 100 but does see relatively cool nights. It is an ideal area for this. I would say from southernmost california to southernmost texas, this basic setup is pretty workable and that includes something around 50 million americans. Regulator hurdles in some places make it impossible though. Costs are going to scale up mostly in line with the heating/cooling requirements and cloudiness of your area.

My panels are ground mounted and pointed in the ideal direction. I think this contributes to their efficiency because the ground helps cool them during the hottest periods but it is a tricky thing to nail down. On a previous home I had roof mounted panels and they seemed to perform much worse, difficult to identify the exact reason though.

In that part of southwest there are only a handful of cloudy days per year and at a relatively low latitude.

What’s the charging/discharge power of your battery? Is it AC or DC coupled?