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What a year of solar and batteries saved us in 2025

scotthelme.co.uk

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Re: What a year of solar and batteries saved us in 2025

#301

Post by scarecrowbob »

ozim wrote: post #261
chasd00 wrote: post #250

Earlier quoted context omitted.

"licensed electrician" is also timewalled behind a lengthy apprenticeship. From google's llm "..requiring 8,000 hours of on-the-job training (OJT) under a Master Electrician .." so even if you could pass the test you still don't get to become licensed until you've paid your dues in terms of time.

Isn't there an exclusion or lower entry requirement if you have a technical education like engineering degree? Like if not electrical engineering because I guess that would be obvious there should be lower entry bar - but for all others at least somewhat related... I guess if you want to dabble with installing battery packs with inverters, that's not your typical bachelor of arts who is trying to do so.

I mean, my MA is in Rhetoric... but hey.

Where I am at (rural CO), as long as it can be inspected and meets code, the county is fine- you don't need a blessing. Septic is different (that's a $175 certificate, though). But for electrical all you have to do is meet codes, which isn't really super hard.

Re: What a year of solar and batteries saved us in 2025

#302

Post by Scott_Helme_ »

elAhmo wrote: post #25

Great read! I am just wondering would stacking up batteries, charging them off-peak and using/selling back during peak usage be as good as this, or even better? Seems like this shouldn't be a viable scenario, but given the prices and idle capacity, it seems just investing in batteries and charging them at night, to be used/sold to the grid during the day would be as good as a solar installation.

We had an expensive solar install due to restrictions around our roof, so the solar would typically have been cheaper.

Another consideration is that battery installations in the UK are charged at 20% VAT, but if they're installed as part of a solar installation, they're charged at 0% VAT. So even if your main interest is in getting the batteries, a small solar install might make sense because of the savings.

Re: What a year of solar and batteries saved us in 2025

#303

Post by magicalhippo »

abdullahkhalids wrote: post #282
LordDragonfang wrote: post #231

Earlier quoted context omitted.

Huh, unexpected is right. Bursts of heavy usage being better for longevity than steady usage goes against pretty much all conventional engineering wisdom.

Without knowing anything about it, I would posit that degradation accelerates the longer the battery is kept above some threshold temperature. So, a heavy-burst+low results in a sudden high temperature then settling into a lower temperature. Steady flow keeps it at moderate temperature (above threshold) for a long time.

The paper notes there are multiple degradation mechanisms at play, and they are influenced by different factors, such as age, cycles, depth of discharge, state of charge at rest and so on. Hence the non-trivial response to more realistic discharge curves.

However they also note more material studies are needed to understand these mechanisms better.

Re: What a year of solar and batteries saved us in 2025

#304

Post by Scott_Helme_ »

HexPhantom wrote: post #148

This setup only really works because of a very specific combination of smart tariffs, EVs, and aggressive automation. Without those, the math would look very different

Absolutely — tariff choice, storage, and automation make a huge difference.

The article isn’t claiming this setup is universally optimal, just showing what’s possible when those pieces are combined and used deliberately.

Re: What a year of solar and batteries saved us in 2025

#305

Post by Scott_Helme_ »

dlisboa wrote: post #179

It's crazy how power hungry UK homes are, or maybe it's UK power consumption habits in general. I use about ~300 kWh/month. A little bit more with AC some times of the year. What are you even powering with 15000 kWh?

I did try to make it clear in the article.

We're powering 2 x EVs, have two adults working from home full time, I have a server rack under the stairs, and we have a hot tub outside.

Re: What a year of solar and batteries saved us in 2025

#306

Post by rv3392 »

pjc50 wrote: post #50
boringg wrote: post #34

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…

> I'm assuming you re-did your roof before you installed In the UK I would expect the roof to be tile, which lasts basically forever unless a storm hits hard enough. I did have to have my panels taken down and refitted, at a cost of well over £1000, because I hadn't bird-proofed underneath them (wasn't suggested by original installer). So watch out for that one.

How do you bird-proof them?

Re: What a year of solar and batteries saved us in 2025

#307

Post by mbesto »

chris222 wrote: post #269
mbesto wrote: post #52

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…

Yah, check this one out. https://www.docanpower.com/panda-52v-942ah-48kwh-prebuilt-pa...

I actually own three of 15 kWh versions :)

They are cheap and they work but they're not UL listed...so they dont go anywhere near my home.

Re: What a year of solar and batteries saved us in 2025

#308

Post by rmcpherson »

jstsch wrote: post #76
j2kun wrote: post #28

Earlier quoted context omitted.

I do wish I could have a good, in-depth tutorial on how to set this up myself. Along with (pipe dream) an explanation of how it would interact with my local utility. I worry that due to some silly technicality, I won't be able to export to my local utility, or else I won't be able to run off-grid when there's an outage.

I will do a write-up in a couple of days. It's all relatively simple, you just have to expect terrible documentation and do a bit of reverse engineering and serial sniffing. I expected the battery to be complicated, but it turned out that the inverter was. You'll encounter stuff like: manual says use RS485 port on Battery for GroWatt inverter → need to use CAN port on Battery. Meter Port (RS485 [serial] over RJ45) wi…

I would appreciate this write up as well. Looking to do a DIY setup.

Re: What a year of solar and batteries saved us in 2025

#309

Post by ViewTrick1002 »

greycol wrote: post #222
jillesvangurp wrote: post #165

Earlier quoted context omitted.

There's going to be a bloodbath in that market in the next years. There are a lot of battery producers and most of them are not producing at full capacity. At the same time, manufacturing cost is dropping as well. Some battery makers are producing batteries at a cost level of around 60$ per kwh. At that cost, the 16kwh battery would come out below 1000$ (not the same obviously as the product price). Sodium ion might…

One thing to remember is as it becomes more widespread line costs will go up (assuming they are subsidized by kwh use, which they generally are) and no-sun power prices will increase as it's the only time when the grid needs power from non solar producers and they still need to cover cost incurred while they're not producing. That will push the economics towards completely off grid systems as more people adopt solar,…

An interesting possible is the grid becoming smaller. Neighborhood scale.

In many places from Central Europe and further north dealing with arctic cold spells and dunkelflautes are near impossible for a home solar and storage setup.

But you also don’t want to pay for a continental scale grid the remaining 51 weeks.

So in your neighborhood add some wind power and a good old trusty diesel/gas turbine running on carbon neutral fuel and keep the costs to a minimum.

Re: What a year of solar and batteries saved us in 2025

#310

Post by lm28469 »

MisterTea wrote: post #295
lm28469 wrote: post #29

Earlier quoted context omitted.

Get a basic heat recovery unit, it basically has no moving parts (just a few fans) and good ones recover 90%+ of the heat going out of your house. It's almost useless if you don't have an airtight envelope though. All in one systems with water heating are way too complex and _will_ fail relatively quickly, mini heat pumps won't last 10 years, and by the time it dies you won't be able to find a replacement for your sp…

> All in one systems with water heating are way too complex and _will_ fail relatively quickly, ... Can you offer some evidence of this? I don't see how adding a refrigerant to water heat exchanger after the compressor, before the reversing valve, could possibly hurt the longevity of a system. > ... mini heat pumps won't last 10 years, and by the time it dies you won't be able to find a replacement for your specific…

> Can you offer some evidence of this? I don't see how adding a refrigerant to water heat exchanger after the compressor, before the reversing valve, could possibly hurt the longevity of a system.

The nearly infinite amount of forum posts about heat pumps dying prematurely and costing thousands and thousands to fix. You don't see how adding complexity on top of complexity in a complex system add points of failures ?

> Thing with mini-splits is you replace the entire unit so it doesn't matter.

I forgot this is an american centric forum and things are just made cheap/disposable because "it's cheaper'

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