121–130 of 368 posts
Except that after 11 years the equipment will have broken down or become obsolete, at which point you have to start over.
> we've also had protection against several power outages in our area along the way, which is a very nice bonus.
This seems to be the real benefit of the setup.
Good analysis. And kudos to the author for saving money. But still 21.6MWh per year excluding solar production seems too high for a household. I use electric heating and drive an electric vehicle, and my household annual energy consumption is about one fifth of that.
I'm an example more towards the middle. In 2025 I produced 6.5MWh (solar) and consumed 12.7MWh (excluding solar production); this is a family of 4 in a 4 season climate with electric heating and a single electric car. That was my highest year over the past 5 years. An additional EV can really add up, especially if both people have long commutes.
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Almost all simulations I've done across 3 countries with 3 different payback models for selling back to grid (one of the three doesn’t allow selling back almost anything above your consumption), I could never make investing in Solar not being a gamble. You really need to gamble on odds of replacing equipment being very low for it to make sense. And in practice most people I anecdotally know that run it, after 5-7 yea…
Having power when your entire neighborhood is off, priceless. [edit: yes, I assume you also get batteries, I know that solar alone doesn't magically power your house.]
Battery/solar doesn’t make sense in my opinion. Too many years to break even like this parent comment said and by the time you break even at 10 years, your system either is too inefficient or needs replacing. At least with the portable generator, you can move it with you to a new home and use it for other things like camping or RVing.
It's wild how overpriced Tesla Powerwalls are. 16 kWh battery with all of the UL supported listings etc = $3300 [0] 13.5 kWh Tesla Powerwall is $12k~$15k You would get your return way back quicker. [0] - https://www.ruixubattery.com/product-page/lithi2-16-battery-... EDIT: As others have pointed out, powerwalls have inverters built in so it's not totally apples to apples. You can get a beefy inverter for $5k and it's…
You're comparing the cost of a battery with a full system. That 16 kWh battery requires a ~$3000 inverter to go along with it.
Better comparison:
Author's config:
3x Powerwalls + inverters = 40 kWh
4.2 kW array
£39,360 = $53k USD
Alternative:
EG4 18kPV Hybrid Inverter = $5000
3x RIUXU = $9600
10x Trina Solar 435w panels = $1580
Cabling, installations, etc. = $5000
Total = $21k
It's not even close...
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Is delivering back to the grid economical in California? Where I'm from people disconnect solar panels on sunny days because it costs them money to return to the grid.
The worst that happens is you get paid back at the wholesale rate (from your bill, not live market price) instead of discounting kwh-per-kwh.
Neither technology can move forward until there's a 100x leap in electricity storage costs. Like a bunch of us said 10 years ago, because we remembered high school physics.
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This is factually inaccurate. Solar PV panels will continue to produce power at 80-90% of rated output after 25 years, and battery storage will still have 80-90% capacity. I'm sure you can understand that as long as the system is storing and producing power at these levels, its value is not zero.
> Having our full costs returned in ~11 years is definitely something we're happy with Except that after 11 years the equipment will have broken down or become obsolete, at which point you have to start over. > we've also had protection against several power outages in our area along the way, which is a very nice bonus. This seems to be the real benefit of the setup.
As for your other point of becoming obsolete, why care about chasing latest fads for home appliances.
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LFP batteries are as likely to burn down your house as a stack of wood is. I'd be worried about the inverter or botched DIY wiring (especially not to spec torque on terminal connections and botched crimps leading to hot spots), but not about the batteries themselves. For a person who wants to save some money, but doesn't know how to work with electricity, the best move is probably to get cheap LFP cells from China, b…
> especially not to spec torque on terminal connections and botched crimps leading to hot spots This was indeed my greatest concern. However the battery came with pre-crimped very solid DC wires, and nice push connectors for the battery itself. The battery also has an integrated DC breaker (great!). The system runs 3KW max, so I just added an additional breaker (with RCD integrated) in the conduit box. In NL this is…
I'm not interfacing with a grid, and there are already code issues with my places- I'd probably feel different if I could get insurance on my place.
Cheap chinese tooling and youtube (plus pretty good general literacy) go a long way in this world.
And FWIW, I live in the US west and am way more worried about fire coming from outside than from the batteries.
9-11 year payback isn't bad based on the projections. You could probably goose it a bit with inflation of electrical prices (depends on how the electrical policies change and what they pass through). I'll also add theres some O&M coming down the line. Inverters @ year 10, small maintenance and Im assuming you re-did your roof before you installed. Anyone putting solar up make sure you do it at the same time as a roof…
Wont you need to replace the batteries around Year 10 and then this becomes a wash?
Curious!
Even if they're at 50% capacity, they would still work, right? But if there are other considerations, especially safety ones, then that would definitely be a consideration. I'm not sure where to learn about this type of thing.