Another 'leccy question

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llondel
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Re: Another 'leccy question

#21 Post by llondel » Tue Nov 30, 2021 9:34 pm

Boac wrote:
Mon Nov 29, 2021 10:12 pm
Out of interest, what sort of cost for a decent battery and 240V inverter?
That depends on what you want it to achieve. A 1kW computer UPS cost me just under $200 a few years ago but it has a couple of the small 12V 7AH SLA batteries inside which will survive no more than ten minutes on full load.In theory the same electronics, assuming it doesn't overheat if run like that for more than ten minutes) would run a lot longer with a larger battery, but would also take longer to recover because it's designed to charge the two smaller batteries.If you're looking at running 5kW then you're getting into serious money and a lot of battery. You'd probably want 48 or even 96V of battery because 5kW at 12V is 400A and you're wasting a fair bit heating up the wires.

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Re: Another 'leccy question

#22 Post by unifoxos » Wed Dec 01, 2021 9:30 am

On the bill for my recent installation the 5kW inverter was charged at £1230, the 8.2 kWh battery at £2500. There is a fair bit of extra kit itemised, isolators, meters etc, totalling around £200. If doing the installation oneself, you can buy this stuff a bit less than that from suppliers on the web. A good sparky could do it on a day - local reliable guy here charges £350 a day for labour only, includes his app. The batteries come in modules and this brand (givenergy) can be configured up to about 12 kWh.

I wanted a professional install to get the MCS certificate I need to get paid for exporting surplus solar from the panels, otherwise I'd have saved a few hundred by doing it myself. I was, however, originally trained to IEE standards when I started work and consider myself capable of doing mains work (we were trained up to 11kV) but it has meant keeping up with the regs that seem to be changing more frequenty these days.
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Re: Another 'leccy question

#23 Post by Boac » Wed Dec 01, 2021 10:02 am

Thanks for all the info. Whilst I live in the (already 'levelled-up' Boris Land) and have a reasonably reliable elec supply, I am concerned at the recent severe hardships in the north of UK caused by the recent weather and feel a back-up would be a prudent consideration.

Cost-wise the genny route seems to be far more effective and would run for an unlimited time as well if needed and enable at least my gas powered c htg and a few lights to run.

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Re: Another 'leccy question

#24 Post by unifoxos » Wed Dec 01, 2021 12:57 pm

Very true - a self-starting genny of a suitable size for a house can be had used (which often means tested once a month for 5 years) for half the price. 'Course, theres a maintenance overhead - the monthly testing, annual oil and filter changes, keeping a good stock of fuel.....

Fuel is less of a problem if you have mains gas, of course.

I
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Re: Another 'leccy question

#25 Post by barkingmad » Thu Oct 06, 2022 11:33 am

Good to know our UK taxman continues to screw money out of those who wish to utilise energy saving measures;

"It is important to know that when installing a battery with a home solar panel system the VAT is 0%, however when retro fitting a battery storage system the VAT in 20%."

So basically if you're going PV + Battery ab initio, you're not penalised but if already using mains tied PV, then a battery retrofit will cost more.

Same UK VAT taxation madness applies to retrofit insulation, double glazing and any other improvements which would save energy.

Hence it's cheaper to demolish buildings with all their embodied energy by way of bricks & mortar down to brownfield site status and start again, proof positive that our politicians display little evidence of basic science education?

Hence the UK moneyman, Kamikwaze, is most unlikely to change this taxation ruling despite the current (NPI!) craze for so-called "greening" of our economy. X(

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Re: Another 'leccy question

#26 Post by Undried Plum » Thu Oct 06, 2022 12:47 pm

When I had the second Powerwall battery installed it was attached to a new electrical control panel which allows me to use the system large pv array and a wonky windturbine) during a powercut. The installer suggested that I add a couple of extra solar panels to the already existing quite large array. He explained that he could then charge 0% VAT as the thing would count as a 'new' installation.

Some taxes are pretty much voluntary, y'know. You just have to know how to play the game by the rules, that's all.

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Re: Another 'leccy question

#27 Post by Undried Plum » Sat Oct 08, 2022 12:12 am

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Re: Another 'leccy question

#28 Post by llondel » Sat Oct 08, 2022 1:08 am

I learned something about the PG&E tariffs recently. We have what is a fairly good feed-in tariff for our solar, we used a net of about 75kWh over the last billing year, and in theory that's what they charge us for. However, because the true-up bill seemed a bit large for that difference, I had a closer look at the tariff terms, and it seems that they can charge us somewhere between 2 and 3 cents per kWh delivered, even if it's subsequently offset by us sending them one. This changes my usage pattern - previously I was running the washing machine and dishwasher overnight on the basis that the grid was less loaded than during the peak of the day with the sun blazing down and all that air conditioning adding load to the grid in addition to normal daytime use. Clearly it's to my advantage to run all my stuff during the day so I'm using my own electricity and not exporting it to them, if it's going to cost me to lend it to them during the day and get it returned at night.

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Re: Another 'leccy question

#29 Post by Fox3WheresMyBanana » Sat Oct 08, 2022 1:16 am

So, their billing system is set up to catch you out doing the decent, logical thing.

Whilst they are appealing to people not to overload the system during peak hours, they simultaneously penalize you financially if you do that?

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Re: Another 'leccy question

#30 Post by llondel » Sat Oct 08, 2022 2:45 am

Fox3WheresMyBanana wrote:
Sat Oct 08, 2022 1:16 am
So, their billing system is set up to catch you out doing the decent, logical thing.

Whilst they are appealing to people not to overload the system during peak hours, they simultaneously penalize you financially if you do that?
Apparently so.

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