[duffpkg]

I have a home in the southwest that is offgrid and runs entirely off solar. It has a 43kwh battery that covers 100% of it's needs including AC. It has a 4kw solar array.

The batteries shipped to your home inclusive of all taxes and fees, UL listed, are only $5,400 today from a variety of reputable suppliers.

This is obviously different than urban london but I wanted to point out just how economical this is for huge swaths of the country and how absolutely absurd some of the pricing I see on things like tesla powerwall are.

Note: There are a lot of components to an installed battery system that effect pricing such as racking, wires, busbars, breakers, etc, etc. I am referring only to the enclosed battery units with BMS.

[oori]

The ratio between storage capacity and production power seems way too low, unless your daily consumption is ~10-15kWh and your batteries are over spec for harsh winter days (and then you’d need couple of sun days to recover). Are you sure about these numbers?

[duffpkg]

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.

[_zoltan_]

if you could tell me where I could get UL certified 43kWh battery for $5,400 I'd be very interested.

[mediaman]

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.

[thechao]

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.

[mbesto]

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.

[duffpkg]

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.

[IncreasePosts]

If it's anything like my slice of the southwest, what works there may not work for a majority of Americans.

Even when it gets very hot in the day(100+), the nights almost always drop down to 63 or less. Meaning if you have a well sealed house you can suck up cold air during the night and ride it out in the day and have very low cooling costs. Coupled with low humidity from an arid environment means you can also let the house get hotter before it feels like it is time to turn on the AC.

[duffpkg]

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.

[Izikiel43]

> The batteries shipped to your home inclusive of all taxes and fees, UL listed, are only $5,400 today from a variety of reputable suppliers.

What about installation? DIY?

[duffpkg]

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.

[more_corn]

The system I’m looking at costs twice as much for half the capacity. I’m very interested in what brand and model you speak of.

[duffpkg]

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.

[jorblumesea]

how are you able to charge 43kwh on such a small array? we have a 12 kwh setup and it recharges a 15 kwh battery in a few hours.

[duffpkg]

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

[lnsru]

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

[fyrn_]

What are these batteries?

[duffpkg]

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.