Discussion
Shaw Tarse said:
Interesting, thanks.HTP99 said:
Do you buy these or is it some trial thing, if you purchase it what's the cost relative to what electricity is stored and returned to the grid?
You buy. Installed cost is around £7500-£8000 and it hold 13 kWh. Or about two quids’ worth - I will get one when capacity is bigger for the cost and when I get solar. The fastest you could possibly get the money back is ten years. For us being able to keep going when there is a power cut (once a year or so in the countryside) would go some way to making it worthwhile but it’s not financially viable yet They are usually bought with solar PVs to help capture solar energy and shift grid electricity usage from peak to off peak times.
When bought with solar PV you can avoid VAT, if you bought+install as standalone (so have to pay VAT), its around £10k fully installed with gateway hardware.
Ours has been installed for 12 months now, its effectively allowed us to cover 40% of total electricity usage with solar.
Total cost of install would take 10 years+ to recruit back from electricity savings, you don't install theses for pure financial reasons.
When bought with solar PV you can avoid VAT, if you bought+install as standalone (so have to pay VAT), its around £10k fully installed with gateway hardware.
Ours has been installed for 12 months now, its effectively allowed us to cover 40% of total electricity usage with solar.
Total cost of install would take 10 years+ to recruit back from electricity savings, you don't install theses for pure financial reasons.
oop north said:
HTP99 said:
Do you buy these or is it some trial thing, if you purchase it what's the cost relative to what electricity is stored and returned to the grid?
You buy. Installed cost is around £7500-£8000 and it hold 13 kWh. Or about two quids’ worth - I will get one when capacity is bigger for the cost and when I get solar. The fastest you could possibly get the money back is ten years. For us being able to keep going when there is a power cut (once a year or so in the countryside) would go some way to making it worthwhile but it’s not financially viable yethttps://www.itstechnologies.shop/collections/unint...
They have packages with greater capacity per £ than the Powerwall: 9.6 kWh for £2000 + installation, for example. Of course it may be a case of getting what you pay for....
cailean said:
Tesla isn't just a car company, they are big in solar panels, roofs, power packs, AI, software, and oh they build cars too, all of that is why the company is worth more than most people think they should be and why they are seeing exponential growth.
There's a whole other thread on Tesla survival 
.Mikehig said:
They have packages with greater capacity per £ than the Powerwall: 9.6 kWh for £2000 + installation, for example. Of course it may be a case of getting what you pay for....
Other options are cheaper but the Tesla software integration is fantastic, I doubt any of other solutions comes close interms of ease of use. The data/control is all done via the same Tesla app on the phone, and you can download historical data for more detailed analysis if that's your thing.A single PW can also discharge at a sustained 5KW which alot of other products cannot, if you had x2 PWs that goes up to 10KW. 10KW is a massive amount of electricity to pull at a sustained rate for any household, I think PWs are of the battery products you can charge an EV from without too much worry.
Edited by gangzoom on Saturday 7th November 04:54
CheesecakeRunner said:
Not everyone installs these things to save money. I’m planning a solar and Powerwall installation that will never pay for itself, but it will remove any need for me to consume grid electricity. That’s more important to me than the cost.
Once I can similar something similar to remove my minimal use of mains gas, that’ll go too.
Out in the countryside, we use logburners! We have LPG as well. I have been looking at ASHPumps but that will neither pay for itself in a reasonable time, and, I fear it will be noisy. Also, being in a conservation area has limitations.Once I can similar something similar to remove my minimal use of mains gas, that’ll go too.
Anybody know the efficiency (95+%, I guess?) of these batteries?, and life?
gangzoom said:
Amazing offsetting!! How big is your solar PV array?
Am really keen to get more solar +/- add another PW. But cannot quite get my ahead around all the permissions etc that's needed for a larger setup.
Mornin' GZ,Am really keen to get more solar +/- add another PW. But cannot quite get my ahead around all the permissions etc that's needed for a larger setup.
It's a 5.95kWp array - biggest allowed without special dispensation from the network provider (Western Power with me). They were very quick with the approval too, very efficient.
Half the year I think the array is too small, half the year too big, so I reckon it's about perfect
It's a tad bigger than the installer first came up with, I wanted to use as much of the roof area as sensibly possible so persuaded them to embiggen the array. The roof is 'interesting' so I have panels on every face that gets sun, which spreads the generation quite a bit through the hours of daylight.While it's good thing for the vast majority of folk, the tariff cap has somewhat screwed up the repayment calculations! I was reckoning on prices going up quite a bit to help reduce the payback time, but hey ho, my pain is pretty much everyone else's gain, so I won't complain. The whole system cost way less than I've already lost in depreciation on the car, so what the heck.
I also went with an immersion heater diverter tied into the inverter...but really don't think it was worth the cost. At best it saves me about 3kWh a day when there's a surplus of solar. You can get much cheaper diverters but I was unsure about how nice they would play with the system so went with the expensive SolarEdge one.
I don't have a dual tariff so haven't made use of the overnight top-up feature. Can't get my head round the idea that you need a fully functional crystal ball attached to the PW for that to pay off?? Assume you charge it overnight - next day the sun shines and all your solar gets exported - at the absolute best you'll break even, assuming low rate cost is the same as feed-in payment. In my case, I'd be paying them 10p per unit effectively.
I did look at the backup mode, but it's not line-interactive UPS style, and it isn't cheap, so I didn't bother getting it upgraded. Our power is pretty reliable and sods law being what it is, you can guarantee the powercuts would arrive when there is no sun or no battery reserve left.
Chris-S said:
I don't have a dual tariff so haven't made use of the overnight top-up feature. Can't get my head round the idea that you need a fully functional crystal ball attached to the PW for that to pay off??
I'm actually surprised at how well the PW manages the overnight/day time charge cycles. Tesla doesn't give any direct control on how much to charge the PW to overnight, you set up the 'off peak' time and the AI software does the rest. I've read conflicting reports on if the PW actually looks the next days weather forecast or not, but over the last year I can only remember a handful of times when I wished it had charged to 100% overnight as we had run it down to 0% through the day.For example last night the PW software decided to take no energy from the grid, which means we started the day at around 75% SOC, looking at the weather today I think its about right.
I know some people enjoy working out numbers/demands, but I just like the fact the software just works, so I don't have to mentally think about it.
In terms of tech, I think our PW is actually far more useful than our car. It's literally in use 90% of the time, either charging or discharging, the car spends 95%+ the time sitting idle doing nothing apart from depreciating
. 
Pica-Pica said:
Anybody know the efficiency (95+%, I guess?) of these batteries?, and life?
Efficiency is a bit less than 90% I seem to remember, there is a 10 year warranty on the battery (I think?). The demand shifting ability of these PWs really cannot be over stated. Since getting ours we hardly ever use any 'peak' electricity. This is our bill from last month when there really wasn't much sun. We used 350kWh of over night cheap electricity versus just 20kWh of day time.
In the never ending 'debate' about how the national grid will cope with increasing number of EVs charging, load shifting is surely a one of the key tools available to help smooth out demand and reduce peak variation.
Edited by gangzoom on Saturday 7th November 09:58
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