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On-grid domestic battery storage
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I reckon it's still about 10p for me. I paid £3k for my 6.3kWh Solax. I reckon this started life as about 5kWh useable (also taking into account round trip losses). The warranty is 10 years and an estimate of over 6,000 cycles. I'll generously go with 6,000 cycles. This means 1.6 cycles a day which as I charge at night and from PV is probably fair. I make this a total of around 30,500kWh saved over the life of the battery. So what previously looked like a vanity project now finally looks like it may possibly be financially viable.Install 28th Nov 15, 3.3kW, (11x300LG), SolarEdge, SW. W Yorks.
Install 2: Sept 19, 600W SSE
Solax 6.3kWh battery2 -
I assume that if you are adding to it in off peak then you need to add the unit rate too but with unit rates of peak at about 25p then it is still making money?5KW solar, Lux 3.8KW inverter, Uhome 2400 LPF x 6, SOLIC 200 immerser diverter, Leaf 62Kwh, MG ZSev, Ohme home charger, Zappi v2.1, Import: Octopus intelligent ; Export: Octopus Energy Export, 15KW biomass pellet boiler - Windhager., Home Assistant (newbie)1
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Martyn1981 said:Can I ask a general question / bit of advice?
Way back at the start of this thread I think I calculated that the cost of storage was about 10p/kWh*. It wasn't a fair estimate, but just an early one for reference. I used a Powerwall II, and based it only on the warranted cycles (at the time). I think I explained that I wasn't trying to be overly hard, just taking an early days position till we'd had more experience of batts, and how well they lasted.
*I divided the cost by the number of kWh's, which in turn was based on the sensible useable amount of capacity times number of cycles, times again by 90% to represent an average capacity slowly dropping to 80% over that time period. I don't know if that is still considered the best/reasonable way to calculate it?
So now that so many of you have batts, that seem to be working really well, and are paying far less (per kWh) to buy them, and it seems the expected cycles have risen(?) what would be a fair estimate for the cost of domestic sized storage now .... 5p/kWh ..... less .....?
Thanks for any advice.——-
12 x JASolar 455w Panels (5.46kWp south facing array) Enphase Microinverters IQ7+, Lux AC ESS 3.6kW, 5 x 2.4kwh = 12kWh Plyontech US2000C Battery storage, Lochinver far North, west coast of Scotland2 -
That calculation is fine if you are doing a d-i-y addition to an existing battery system but for a new installation you need an inverter and for most people there will be racking, cables and labour for installation and profit to add. It’s a bit like calculating the cost of solar PV based purely on the cost of buying the panels from a wholesaler.
Edit: and you may also have DNO costs to consider.Edited again to show the post I was replying to.Northern Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, Solar IBoost water heater, Mitsubishi SRK35ZS-S and SRK20ZS-S Wall Mounted Inverter Heat Pumps, ex Nissan Leaf owner)0 -
I wanted some back up power for emergencies and having failed to get past the DNO opted for a very simple stand alone solution. The cost is around 60% more than a pylontech battery but includes an inverter and facility for direct charging from a solar panel. I have ordered a 330w panel just to power the PPS. Once I get a mounting frame made I can track the sun to get optimum generation and should be able to recharge the PPS in around 8hrs on a good day.I used it to cook my toast this morning.Northern Lincolnshire. 7.8 kWp system, (4.2 kw west facing panels , 3.6 kw east facing), Solis inverters, Solar IBoost water heater, Mitsubishi SRK35ZS-S and SRK20ZS-S Wall Mounted Inverter Heat Pumps, ex Nissan Leaf owner)1
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EVandPV said:Hi Mart, purely based on the cheapest deal currently for new Pylontech batts, not including an inverter and if I'm reading your calculation right >2.4kwh x 90% = 2.16kwh x 90% = 1.94kwh£750 / 1.94kwh = £386.60 / 6000 cycles = £0.06
Looking at Wright's Law / technology learning curve, it seems for batts it's very high with estimates between 18% and 28% for every doubling of production. Just spit balling but if production can double 3x in the next 5yrs(?) then with just a 20% learning curve, that £750 price could become £384. All very promising.
[Obviously I'm ignoring the current world upheaval and hoping it all settles down asap.]Mart. Cardiff. 8.72 kWp PV systems (2.12 SSW 4.6 ESE & 2.0 WNW). 20kWh battery storage. Two A2A units for cleaner heating. Two BEV's for cleaner driving.
For general PV advice please see the PV FAQ thread on the Green & Ethical Board.0 -
Martyn1981 said:EVandPV said:Hi Mart, purely based on the cheapest deal currently for new Pylontech batts, not including an inverter and if I'm reading your calculation right >2.4kwh x 90% = 2.16kwh x 90% = 1.94kwh£750 / 1.94kwh = £386.60 / 6000 cycles = £0.06
Looking at Wright's Law / technology learning curve, it seems for batts it's very high with estimates between 18% and 28% for every doubling of production. Just spit balling but if production can double 3x in the next 5yrs(?) then with just a 20% learning curve, that £750 price could become £384. All very promising.
[Obviously I'm ignoring the current world upheaval and hoping it all settles down asap.]
1st - Taking this thread off course a tad by raising commercial costs.
2nd - Replying to myself.
But my reply reminded me of the pricing that came out last year for Megapacks, which does project a nice cost reduction, suggesting perhaps that the cost/kWh of commercial scale storage is, perhaps, half. Fingers crossed may it continue.With 10 Megapacks, Tesla lists a price of $9,999,290, which results in a price per kWh of $327.87.
However, that’s not an accurate representation of Tesla’s battery costs since it also includes 7.6 MW of power inverters and installation.
Tesla describes the installation process of the Megapack:
1. Project design (including electrical and civil)
2. Project permitting (ministerial only)
3. Project construction (including electrical up to 480V, grading and foundations, mv transformer as applicable)
4. Project commissioning
5. Backup capability for critical loads
The price per kWh goes down as you order more Megapacks. 100 Megapacks brings the cost down to around $280 per kWh.
The configurator also reveals an annual maintenance cost, which escalates at 2% per year.
Tesla reveals Megapack prices: starts at $1 million
Mart. Cardiff. 8.72 kWp PV systems (2.12 SSW 4.6 ESE & 2.0 WNW). 20kWh battery storage. Two A2A units for cleaner heating. Two BEV's for cleaner driving.
For general PV advice please see the PV FAQ thread on the Green & Ethical Board.2 -
My pylontechs degrade about 1% for every 200 cycles. On this basis it’ll take 6000 cycles to reach 70% which is 1500 cycles better than the guarantee.
(849 cycles to date)4kWp (black/black) - Sofar Inverter - SSE(141°) - 30° pitch - North LincsInstalled June 2013 - PVGIS = 3400Sofar ME3000SP Inverter & 5 x Pylontech US2000B Plus & 3 x US2000C Batteries - 19.2kWh3 -
I think LiFePo batteries will have better lifetimes than was originally predicted. Batteries in EVs are now expected to last the reasonable life of the car.3
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1961Nick said:My pylontechs degrade about 1% for every 200 cycles. On this basis it’ll take 6000 cycles to reach 70% which is 1500 cycles better than the guarantee.
(849 cycles to date)
Not seeing any percentage difference from when I tested mine last year at this time.
Mine don't cycle every day and I have 4 connected to both inverters so less strain per battery.
Similarly due to a fairly large solar array and a fairly large daily consumption, I'm finding that for every complete full to complete empty cycle, I'm having another couple of half cycles, and so as the 6000 cycle warranty is full to empty, I'm looking at more like a 12000 cycle warranty.
West central Scotland
4kw sse since 2014 and 6.6kw wsw / ene split since 2019
24kwh leaf, 75Kwh Tesla and Lux 3600 with 60Kwh storage1
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