On-grid domestic battery storage

mre15

That VAT is a killer, I want to add an additional 2 batteries to my system and its only the 20% VAT that's making me wait. If it was 5% like the original install I would have purchased already.
Batteries are £650 each + VAT so £325 per kWh useable without the VAT.
I want them to be below £350 inc VAT per kWh before I add to basket.

joefizz

mre15 wrote: »

That VAT is a killer, I want to add an additional 2 batteries to my system and its only the 20% VAT that's making me wait. If it was 5% like the original install I would have purchased already.
Batteries are £650 each + VAT so £325 per kWh useable without the VAT.
I want them to be below £350 inc VAT per kWh before I add to basket.

Couple of things..
If buying from an ebay supplier keep an eye out for ebays occasional 10% 15% site wide discounts. Its usually capped at 50 quid but 50 quid is better than nothing.


Probably not strictly legal but if someone near you was doing a clean battery install and somehow needed to order the full rack of 8 batteries and then find they only use 4 maybe they would sell them to you at a good 2nd hand price ;-) Say like 15% off RRP ;-)

zeupater

joefizz wrote: »

... On the subject of extra panels and microinverters, full VAT on those as well so thats why I went through my original install supplier. They get a bulk discount so that offset a lot of the VAT costs and allowed them a little profit. They also delivered them to my door at no extra cost, just waited until they were doing a job near me. So overall was cheaper than me buying in person and getting them shipped to the house ...

Hi

I believe the point made was related to the rate of VAT that applies to a supply & install of qualifying energy-saving products.

Following the rules & installing a solution that includes both new generating capacity & storage moves the whole to the 5% reduced rate of VAT, with the difference between that and the standard rate likely equating to the additional equipment (if everything is well planned!), effectively making the additional generation capacity 'free' ....

HTH
Z

mmmmikey

Exiled_Tyke wrote: »

which can be stored (or more precisely, recovered from storage) over the useful (warranted) life of the battery.

Interesting choice of words "useful (warranted) life of the battery" - but maybe I'm over-analysing / reading too much into them....

I would expect the useful life of the battery to extend well beyond the warranty (as it does for most things you buy). For example, the expected life of the PowerVault batteries is 6000 cycles, which at 1 cycle per days is 16ish years, but the warranty is for 10 years.

If the thinking is that you want to see your money back in the warranty period so you've still got time to see a profit before the batteries reach end of life, I can see the logic there. But if your doubtful of them lasting beyond the warranty period, that does seem somewhat over-cautious to me?

Be interested to hear views on this?

1961Nick

mmmmikey wrote: »

Interesting choice of words "useful (warranted) life of the battery" - but maybe I'm over-analysing / reading too much into them....

I would expect the useful life of the battery to extend well beyond the warranty (as it does for most things you buy). For example, the expected life of the PowerVault batteries is 6000 cycles, which at 1 cycle per days is 16ish years, but the warranty is for 10 years.

If the thinking is that you want to see your money back in the warranty period so you've still got time to see a profit before the batteries reach end of life, I can see the logic there. But if your doubtful of them lasting beyond the warranty period, that does seem somewhat over-cautious to me?

Be interested to hear views on this?

Obviously the number of cycles will depend on the installed battery capacity.

With 12kWh mine is showing 33 cycles after 71 days.

A "cycle" appears to be 12kWh.

zeupater

mmmmikey wrote: »

Interesting choice of words "useful (warranted) life of the battery" - but maybe I'm over-analysing / reading too much into them....

I would expect the useful life of the battery to extend well beyond the warranty (as it does for most things you buy). For example, the expected life of the PowerVault batteries is 6000 cycles, which at 1 cycle per days is 16ish years, but the warranty is for 10 years.

If the thinking is that you want to see your money back in the warranty period so you've still got time to see a profit before the batteries reach end of life, I can see the logic there. But if your doubtful of them lasting beyond the warranty period, that does seem somewhat over-cautious to me?

Be interested to hear views on this?

Hi

Probably find that ET's point covers things other than the batteries, for example the MTBF of electronics, including inverters etc ...


Years ago there was much debate on the lifespan of PV inverters and how this would have an effect on 'payback' with a general consensus that allowance for inverter replacement every 10years would be wise ...

... a number of members of this very board have experienced failures well before 10 years has been reached, but that's just averages (as in 'Mean-Time') ...

For clarification, the cycle duty as used by manufacturers is simply on charge capacity deterioration to a standard preset point, so 6000 cycles would generally be accepted to be to 70% of 'as new' ... ie, a 3.7V 2850mAh (~10Wh) battery cell would be expected to hold 7Wh after 6000 cycles, with the normal caveats of usage as set by the solution manufacturer ... unless there's a form of warranty on the battery solution as a whole which includes any failure, including individual cells, then the cycle performance guaranty alone doesn't necessarily apply ...

HTH
Z

1961Nick

zeupater wrote: »

Hi

Probably find that ET's point covers things other than the batteries, for example the MTBF of electronics, including inverters etc ...


Years ago there was much debate on the lifespan of PV inverters and how this would have an effect on 'payback' with a general consensus that allowance for inverter replacement every 10years would be wise ...

... a number of members of this very board have experienced failures well before 10 years has been reached, but that's just averages (as in 'Mean-Time') ...

For clarification, the cycle duty as used by manufacturers is simply on charge capacity deterioration to a standard preset point, so 6000 cycles would generally be accepted to be to 70% of 'as new' ... ie, a 3.7V 2850mAh (~10Wh) battery cell would be expected to hold 7Wh after 6000 cycles, with the normal caveats of usage as set by the solution manufacturer ... unless there's a form of warranty on the battery solution as a whole which includes any failure, including individual cells, then the cycle performance guaranty alone doesn't necessarily apply ...

HTH
Z

I was one of those that suffered an early inverter failure. It broke down after 5 years 6 months & unfortunately the warranty was only for 5 years.

On the plus side, the new one is more efficient & appears to be heading towards producing around 200 kWh more pa than the old one could manage. It also has a 10 year standard warranty. The extra FIT & battery utilisation actually makes it virtually cost neutral over that period.

Solarchaser

mre15 wrote: »

That VAT is a killer, I want to add an additional 2 batteries to my system and its only the 20% VAT that's making me wait. If it was 5% like the original install I would have purchased already.
Batteries are £650 each + VAT so £325 per kWh useable without the VAT.
I want them to be below £350 inc VAT per kWh before I add to basket.

Not sure if prices have changed, if anything I would hope they have reduced... but anyway I got 2x 2.4kwh pylontech batteries from think renewables in keighley for £1500 inc vat
Worth a visit to their website and send an enquiry, prices may be less as that was 6 months ago.
It was £375 /useable kWh, which doesn't meet your £350/kWh target, but like I say, hopefully they would be less now.
Their delivery charge was hefty as using hazardous network, but I had some work to do near keighley two weeks after ordering so just dropped by and picked them up to save delivery charge.

The vat free on renewables only works if its an accredited company doing everything I believe, so buying a couple of panels with batteries wouldn't do it.... I tried, and that's what I was told.

In regards to Martin's point about usability outside the strict full charge to full discharge, I can confirm that this can be very useful.
I'm off this week and just dragged my lazy !!! out of bed an hour ago.
Went for a 20 odd minute shower with 9.6kw shower, battery on the sofar threw out 2.8kw for 20 mins, and that plus the main fit system and the second system gave me a free shower (why cant the whole family shower when sunny???), but looking now, it's back up to 99% charge, so I've probably saved about 45p with the micro cycle, that without batteries id be paying for.
Sofar system has been in 5.5 months now, battery cycle count is at 54.

I only use the app though, so I cant actually confirm how much the battery discharged.

Folk using the solarman, how do you see the total battery discharge,? as I feel that would be pretty important to the discussion here..

Kev

mre15

Thinkrenewables are still the same price, I already had a price from them and a few others. £650 Plus seems about the lowest so far.

I am going to wait just a little longer, the 2.4 model must start to get cheaper now the 3.5 model is out.

1961Nick

Solarchaser wrote: »

Folk using the solarman, how do you see the total battery discharge,? as I feel that would be pretty important to the discussion here..

Kev

Device>Inverter>Battery>Cumulative Discharge.