Solar panels and battery - any real world reccomendations?

gpuerrilla · 23 Jun 2022 at 13:21

squerble said:
kW are not the same as kWh. We're talking about power here, which is measured in kW. kWh is used to measure energy - if you powered a 1kW kettle for one hour you'd have used 1kWh of energy. If you run a 2kW kettle for half an hour, you've still used 1kWh.

Not trying to be condescending or anything but I noticed in a few of your posts on this topic you've used kWh instead of kW so just wanted to nudge you in the right direction

Apparently overthinking.

They also already make these camping ones so its cheap. I can wait an extra 180 seconds or whatever it is if it means controlling local generation. That's the whole point. :cry:

SoliD · 23 Jun 2022 at 13:27

Out of interest what sort of time when its bright summer sunshine are people hitting close to or max generation from their panels? Weather has been lovely this last week but i'm intrigued to understand what sort of sun is required (whether that is strength or height in the sky) to get your panels really going. Hopefully i'll be able to see quickly once my install is done if we get some good weather, but would be good to have an idea. In theory my panels could have seen sunlight from 5am through to 9pm yesterday bar the odd cloud.

SBo · 23 Jun 2022 at 13:32

gpuerrilla said:
With batteries maybe. My setup wont have batteries. Hence why especially on normal days i.e. cloudy or non-wall to wall sunshine days you dont want to creep anywhere near the 3kw limit as you want to avoid the grid (kettle and high use items will trigger that)!

So to clarify. 3.6KW inverter for me. Limited by DNO regs. Don't assume everyone has the same setup as you.

Time to get a battery

Even a small one will help smooth the load, like when your washing machine is running and a cloud passes overhead….

Did I just open a can of worms?!

BUDFORCE · 23 Jun 2022 at 14:02

The thing with the whole camping kettle, is you need to factor the cost of the kettle in.

It it costs you less than a penny to pull that little bit extra from the grid on a 3kw kettle, how many times do you have to run your lower load kettle before it saves you money?

What if the kettle only lasts say 3-4 years?

squerble · 23 Jun 2022 at 14:05

BUDFORCE said:
The thing with the whole camping kettle, is you need to factor the cost of the kettle in.

It it costs you less than a penny to pull that little bit extra from the grid on a 3kw kettle, how many times do you have to run your lower load kettle before it saves you money?

What if the kettle only lasts say 3-4 years?

Yup, exactly the point of my post. It costs 1p at the current price cap to run the 3kW kettle for 45 seconds, so if it uses only 1 second from the grid before the inverter can get the battery power in there, it's 1/45th of a pence each time that happens. Even if you ran the kettle 45 times a day for a year, that's £3.65 over the year

not worth it.

b0rn2sk8 · 23 Jun 2022 at 14:05

There is also the fact a camping kettle is a pile of ****.

Most instant boiling water taps are usually around 900w for a one with a smaller tank. I’d prefer the latter experience.

BUDFORCE · 23 Jun 2022 at 14:12

Aside from the kettle thing, in general, as much as I want to look after the environment, I don't think it's worth going around replacing things with more energy efficient versions until they get to the end of their natural use.

Our solar install is going on next week, so I'd like to think we are doing our bit, but honestly my main reason for getting solar is the financial investment.

Mrs has a tumble dryer thats probably 20 years old (possibly older) I dread to think how terrible the energy efficiency is on that, but it's just not cost effective to simply replace it whilst it's still working.

simmotech · 23 Jun 2022 at 14:31

it may draw from the grid but the amount from the grid in kwh measurement will be tiny.

Although its very short spurts typically so even a top up from the grid is going to be minor cost

squerble said:
Just worked it out - 3kW (not kWh) over 45 seconds (presuming people use their noggin and only boil a cup's worth) equals about 1p at the price cap rate of 28p/kWh.

All true enough but seeing Grid: 0p on the monitoring software or removing the odd red peak on those chart thingies (showing grid draw) would be very nice!

simmotech · 23 Jun 2022 at 15:00

BUDFORCE said:
Aside from the kettle thing, in general, as much as I want to look after the environment, I don't think it's worth going around replacing things with more energy efficient versions until they get to the end of their natural use.

I'm in the lucky position of moving from the South back to the North West so selling my semi down here means I can buy a detached up there, pay off the mortgage and have enough left to buy solar, air-con (for heating too) and all new appliances - fridge freezer, washer, dryer (and kettle!) all of which will be in the top brackets of energy efficiency. Being a Northerner, I am tight-fisted so I am having a great time doing my research to get the best value for money.
The existing appliances will be left for the new owner of my house as they requested so they won't be wasted.

The instant kettle thing is a bit extravagant I admit (I've had good use of my £20 Asda kettle) but pleasing she-who-must-be-obeyed means I can buy the other gear with less scrutiny.

VaderDSL · 23 Jun 2022 at 15:00

SoliD said:
Out of interest what sort of time when its bright summer sunshine are people hitting close to or max generation from their panels? Weather has been lovely this last week but i'm intrigued to understand what sort of sun is required (whether that is strength or height in the sky) to get your panels really going. Hopefully i'll be able to see quickly once my install is done if we get some good weather, but would be good to have an idea. In theory my panels could have seen sunlight from 5am through to 9pm yesterday bar the odd cloud.

I don't have panels, but I'm looking into them. I used :

JRC Photovoltaic Geographical Information System (PVGIS) - European Commission

Photovoltaic Geographical Information System (PVGIS)

re.jrc.ec.europa.eu

to get the full 2020 yearly irradiance values (satellite based, so presumably they have some algorithm that views the cloud cover from satellite photos and turns it into a defined irradiance value?)

I used the site to generate a CSV with the hourly watt production based on the size of my anticipated array, angle of panels, orientation. I could then estimate the production based on the 2020 year cloud cover (as mentioned above)

I took a couple of data points, a good and a bad day in January

and a good and a bad day in june

Could be worth plugging all your data in and seeing what it throws out?

casper_uk · 23 Jun 2022 at 15:39

BUDFORCE said:
I'm not surprised in the slightest.

Third date is next Wednesday. Lets wait and see if it happens. At least this time the scaffolding has gone up!

Ron-ski · 23 Jun 2022 at 15:42

SoliD said:
Out of interest what sort of time when its bright summer sunshine are people hitting close to or max generation from their panels? Weather has been lovely this last week but i'm intrigued to understand what sort of sun is required (whether that is strength or height in the sky) to get your panels really going. Hopefully i'll be able to see quickly once my install is done if we get some good weather, but would be good to have an idea. In theory my panels could have seen sunlight from 5am through to 9pm yesterday bar the odd cloud.

Midday, but if I look at the two arrays individually they peak at slightly different times as they are at 90 degree's to each other.

Mercenary Keyboard Warrior · 23 Jun 2022 at 16:29

squerble said:
kW are not the same as kWh. We're talking about power here, which is measured in kW. kWh is used to measure energy - if you powered a 1kW kettle for one hour you'd have used 1kWh of energy. If you run a 2kW kettle for half an hour, you've still used 1kWh.

Not trying to be condescending or anything but I noticed in a few of your posts on this topic you've used kWh instead of kW so just wanted to nudge you in the right direction

yeah I know the diff, switching between diff topics and diff things measured means I can use them interchangeably, I am sure people know what I am on about.

I will probably carry on doing that as well, so suggest you live with it

Mercenary Keyboard Warrior · 23 Jun 2022 at 16:33

BUDFORCE said:
The thing with the whole camping kettle, is you need to factor the cost of the kettle in.

It it costs you less than a penny to pull that little bit extra from the grid on a 3kw kettle, how many times do you have to run your lower load kettle before it saves you money?

What if the kettle only lasts say 3-4 years?

I didnt suggest we started going an replacing them, just that in future when people may have the ability to vary demand it would help if very high demand devices allowed a simple way to vary their demand

Sorry to those of you whos minds were blown by this simple suggestion

Many devices if you had a variable surplus could easily heat slower, washing machine, kettle, dishwasher, tumble drier etc
It would actually be a real world usage for the fixation with making everything smart.

Mercenary Keyboard Warrior · 23 Jun 2022 at 16:36

BUDFORCE said:
Mrs has a tumble dryer thats probably 20 years old (possibly older) I dread to think how terrible the energy efficiency is on that, but it's just not cost effective to simply replace it whilst it's still working.

It may well be actually.

Same applies to fridges / freezers. Modern ones use a fraction of what old ones did
Eg modern fridges they say use about a 5th of the energy of a 70s one.

Don't assume its not worthwhile switching a very old inefficient one for a modern one.
Of course it depends on annual usage vs cost, it depends on devices such as tumbles how often they are actually used. Fridges etc are easier to check since they are permanently plugged in.

Doobedoo · 23 Jun 2022 at 18:20

BUDFORCE said:
The thing with the whole camping kettle, is you need to factor the cost of the kettle in.

It it costs you less than a penny to pull that little bit extra from the grid on a 3kw kettle, how many times do you have to run your lower load kettle before it saves you money?

What if the kettle only lasts say 3-4 years?

I’ve had a lower power kettle for quite a while now, it’s great.

iKich Glass Electric Kettle, 1.7L Eco Water Kettle with Illuminated LED, £22.09 at Amazon

iKich Glass Electric Kettle, 1.7L Eco Water Kettle with Illuminated LED, £22.09 at Amazon. ✅ Find more genuine deals & bargains recommended by real people at LatestDeals ✅

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BUDFORCE · 23 Jun 2022 at 18:23

Doobedoo said:
I’ve had a lower power kettle for quite a while now, it’s great.

iKich Glass Electric Kettle, 1.7L Eco Water Kettle with Illuminated LED, £22.09 at Amazon

iKich Glass Electric Kettle, 1.7L Eco Water Kettle with Illuminated LED, £22.09 at Amazon. ✅ Find more genuine deals & bargains recommended by real people at LatestDeals ✅

www.latestdeals.co.uk

Oh yea, not saying it's a bad thing.

And as we are getting solar installed, as and when our kettle breaks would probably go to something like that.

OldKitMan · 23 Jun 2022 at 18:44

I'm looking at a lower powered way to heat my hot tub during the day as the current heater is 2kw but have started looking at seeing if I can get an outdoor pond/aquarium kind of thing as it would be significantly cheaper to heat it for a longer period using less power. need something that wont melt the shell though if it moves about and ends up in contact, and obviously won't electrocute anyone who sticks there hand in without removing the heater.

gpuerrilla · 23 Jun 2022 at 20:09

Mercenary Keyboard Warrior said:
I didnt suggest we started going an replacing them, just that in future when people may have the ability to vary demand it would help if very high demand devices allowed a simple way to vary their demand

Sorry to those of you whos minds were blown by this simple suggestion

Many devices if you had a variable surplus could easily heat slower, washing machine, kettle, dishwasher, tumble drier etc
It would actually be a real world usage for the fixation with making everything smart.

Neither did I, and totally understand most people's posts. My example was continuing on the kettle idea with something I was going to do at some point, like a poster earlier said my ASDA kettle must be over 5 years old now so whenever that decides to kick the bucket, I will likely look at a low power one. When I looked on the rainforest these were similar price to a normal kettle so not sure where people are getting rubbed up by it.

Also the pennies here, pennies there off the grid is going to amount over the year. It may be 28p in the example earlier but what when its 58p?

Its an investment and change of habits somewhat to adjust that's all. It may not have been that good a payback before, but now is one of the better moments to get it done surely.

With other installers and advise sought elsewhere, many experienced folk said the battery may work for some but its not universally epic for all. Looking at the lead times its adding on and their variety in what your investing in, I am not worried about it lets put it that way.

Phoenix211 · 23 Jun 2022 at 20:36

So we are (almost, waiting on an Eddie) installed! Yesterday we spent 1p on electricity and exported enough to cover the standing charge of gas and electricity. Super happy. Installers were excellent and everything has worked first time. 4.9kw of panels, 12kwh of batteries, 5kw LUX invertor and an iboost (kindly provided to use whilst waiting on the Eddie, harvi and Hub to arrive). All for just under £9.5k