Solar panels and battery - any real world reccomendations?

[HungryHippos]

You'll pay 20% VAT on battery without solar panels installed with it.

You'll still need an inverter.

Someone will have to install it. May need DNO application if it can export.

Reliant on a cheap off-peak tariff always existing that you can get onto.

To some degree here you may as well just get panels with it, you're more likely to find a company that is willing to install both in an official capacity. Most installers probably won't entertain just coming along to install a battery only, especially if you buy it and not them.

Does up the cost but then you wind up with best of both worlds, and you can fill your own battery a lot of the time.

 

[Robert]

sawthis, not validated the info and it is from last year:

Home Battery Storage Now Makes Financial Sense // Even WITHOUT Solar Panels // Pay Back Calculations

Home Battery Storage Now Makes Financial Sense without solar panels, assuming you can get on an energy tariff with at least 4 hours Off Peak charging rates.*...

youtu.be

Again, crux would be to just charge when cheap (allowing for tafrif) and use at normal times

 

[HungryHippos]

Yes but installers are much busier now with the higher prices, they have probably booked out slots for months for panel + battery systems. They won't want to spend the time coming to just install a battery as it's less profit for them, and still a lot of the headaches (they installed your system and are therefore partly responsible for it).

Getting onto a cheap ToU tariff like Go technically requires an EV, at some point, if not already, Octopus may require proof that you have one, or may pull the tariff.

The prices quoted are now higher on Go, 12p/kWh off-peak for new customers today.

The price for battery installed quoted in the video is around £3.8K, I'm not convinced you could get one installed for that price now.

Too many variables, why would you not look at options including solar panels as well? really increases your flexiblity in a lot of ways.

 

[Ron-ski]

I think you stand a good chance of a decent electrician installing an AC connected battery, it would be a self contained unit which just needs connecting to the consumer unit. It would still need G98/99 as in theory it could export. Electricians don't like solar as it's outside their comfort zone, and a lot of new regulations to learn, and extra expense if they want to be MCS registered.

Think it was @Bug One that recently installed one a few pages back.

 

[Oh Ed not again.]

Deposit paid, I don't think I've been this excited for something since Super Nintendo Christmas Eve.

 

[Mercenary Keyboard Warrior]

Deposit paid, I don't think I've been this excited for something since Super Nintendo Christmas Eve.

Just a warning, prepare to be disappointed.
Many things seem to go wrong with solar, normally based around availability of parts.
I guess I am saying, prepare for a little stress and/or annoyance. Bonus if you don't get either.

Worth it in the end though.

 

[Zeeflyboy]

Scaffold vanished today, so officially all done now.

Very happy with the system so far, I’ve barely used any peak electricity at all since it went in a couple of weeks ago… combination of the 15kwh packs and big array should see pretty nicely lowered bills going forward all year round.

This month alone I’ve generated 201kWh so far and it’s February… granted there’s been some nice days the last few weeks but still, that’s exceeding my expectations given I’m subject to some pretty extensive afternoon shading issues until (estimated) about mid April.

Big upfront investment, all told after I added some stuff like optimisers, 3 battery packs rather than two, and bird blocker etc it came to about £16.5k in the end.

 

[Oh Ed not again.]

Just a warning, prepare to be disappointed.
Many things seem to go wrong with solar, normally based around availability of parts.
I guess I am saying, prepare for a little stress and/or annoyance. Bonus if you don't get either.

Worth it in the end though.

Noted, I'm fairly pessimistic in my approach to things anyway. 20 years in IT has ingrained it into my soul.

 

[Hawk Tuah]

sawthis, not validated the info and it is from last year:

Home Battery Storage Now Makes Financial Sense // Even WITHOUT Solar Panels // Pay Back Calculations

Home Battery Storage Now Makes Financial Sense without solar panels, assuming you can get on an energy tariff with at least 4 hours Off Peak charging rates.*...

youtu.be

Again, crux would be to just charge when cheap (allowing for tafrif) and use at normal times

You really need to do the sums before considering a battery only.

What's the price difference between the cheap rate and peak rate. How many KW can you effectively store.

Current economy7 is 18/47 so you'll save ~30p for every KW stored. So - say an 9kw battery X 30p, you're looking at around £2.70 saving a day.

However this is ignoring a number of additional factors. The inverter isn't 100% efficient, and will also consume a surprising amount of power itself while running (they've got a big heatsink on the back for a reason).

Plus a 9kw battery doesn't mean you'd be using all of it. You'll have a minimum discharge of ~20% so more like 7kw useable.

I'd guess, after all losses, more like £2 saving a day.

Looking at install quotes, that system has a 7k installation cost. So, 10 years before you even break even.

 

[Mercenary Keyboard Warrior]

You really need to do the sums before considering a battery only.

What's the price difference between the cheap rate and peak rate. How many KW can you effectively store.

Current economy7 is 18/47 so you'll save ~30p for every KW stored. So - say an 9kw battery X 30p, you're looking at around £2.70 saving a day.

However this is ignoring a number of additional factors. The inverter isn't 100% efficient, and will also consume a surprising amount of power itself while running (they've got a big heatsink on the back for a reason).

Plus a 9kw battery doesn't mean you'd be using all of it. You'll have a minimum discharge of ~20% so more like 7kw useable.

I'd guess, after all losses, more like £2 saving a day.

Looking at install quotes, that system has a 7k installation cost. So, 10 years before you even break even.

You need to compare the savings to std rate not eco 7 higher rate.

Its 18p vs 34p.
But with potential negative of 47p vs 34p for any peak units on eco 7 tariff.

Almost every modern battery is 90% DOD, for minimum 10%, although giveenergy quote 100%, it seems to be they are overprovisioned by around 10% already.

 

[Hawk Tuah]

You need to compare the savings to std rate not eco 7 higher rate.

Its 18p vs 34p.
But with potential negative of 47p vs 34p for any peak units on eco 7 tariff.

Almost every modern battery is 90% DOD, for minimum 10%, although giveenergy quote 100%, it seems to be they are overprovisioned by around 10% already.

If you want to get the cheap night rate, then you have to pay the higher rate at peak times. You only get whatever you can store in your batteries carried over at that cheap rate. Any more and you're paying a premium rate. To make it effective you have to shift as much use as possible to overnight.

My battery claims 95% DOD. If you want it to last, then keeping it above 20% is sensible. Once you hit your set % it will continue to drop from that % and if it gets too low it will trigger a forced charge to protect it. You don't want that to happen until you're into your cheap rate gain. Mine seems to drop about 0.5% an hour once it's cut out (it's powering the inverter and BMS still).

 

[Mercenary Keyboard Warrior]

If you want to get the cheap night rate, then you have to pay the higher rate at peak times. You only get whatever you can store in your batteries carried over at that cheap rate. Any more and you're paying a premium rate. To make it effective you have to shift as much use as possible to overnight.

My battery claims 95% DOD. If you want it to last, then keeping it above 20% is sensible. Once you hit your set % it will continue to drop from that % and if it gets too low it will trigger a forced charge to protect it. You don't want that to happen until you're into your cheap rate gain. Mine seems to drop about 0.5% an hour once it's cut out (it's powering the inverter and BMS still).

Hmm let me explain it simpler. With a fully worked example.

Say he uses 15kwh a day. He can get that at 34p, so his baseline is 15x34p = £5.1
This is what his savings are judged against.

If he buys the battery he may use say 9.5kwh charging his battery, and say 1kwh in cheap time. Usage 10.5 at 18p. = £1.89
The rest comes from peak, now assume he gets 8.5 actual usable out of his battery, he needs to pay for 15-1-8.5 = 5.5 at 47p = £2.59
Benefit is best non battery position £5.1 less costs of using the battery, £1.89 and £2.59 = £5.1-1.89-2.59 = £0.62

From all I have read the 20% doesn't apply to home batteries.
Mine your supposed to charge to 50% if planning to leave for months!

Where are yours stored? Mine are outside, if its veeery cold they do drop below 10%, at 5% they apply a very low trickle charge.
Other times they sit at 10% for hours. This is the normal behaviour.
My suspicion is after months of watching the issue is mainly the draw when they hit zero. If its a heavy draw I think they drain more and go below 10% before they shut off and hence when they rebalance they find they are below 10%. When its a light draw they hit 10% nicely and don't over discharge.
Thats my observation from around 3 months now.

Odd your inverter and BMS show active, mine specifically says its gone inactive. If battery was 10% and it starts to charge it shows a different comment in the 5 minute log,i forget the term but something like initialising. Every other 5 mins says either active or inactive.
Could be due to being more advanced as its whole house UPS as well.

 

[NoNameNoNumber]

Are there any go-to apps you guys would recommend for nerding out on my new PV install.
The Sunsynk app is quite decent, but it doesn't show total kW imported from grid.

Also, I don't have a smart meter IHD, was missing when we bought the house. Rather than paying 50 quid for a replacement, is there a decent app for Alexa show which would provide all my electrical metrics as an IHD would, but with the PV stuff too?

Cheers guys

 

[HungryHippos]

My IHD data became entirely worthless when I got solar, the numbers were just all over the shop.

Inverter became the thing to check.

I have mine attached to Home Assistant which allows it to record stuff, but also send data automatically to pvoutput for the team generation stats.

 

[b0rn2sk8]

Home Assistant

 

[Hawk Tuah]

Hmm let me explain it simpler.

In your simpler explanation, is your summary that he'd save 0.62 a day?

My batteries are in the garage. Not heated, but perhaps a little more mild than outside.

I only really know about my own batteries. There's plenty of discussion online about suggested minimum SOC. Some people set it lower. My inverter has default values for PylonTechs and that's what I've left it at. For me, battery longevity is vastly more important than using those extra few % at the bottom.

 

[Mercenary Keyboard Warrior]

In your simpler explanation, is your summary that he'd save 0.62 a day?

My batteries are in the garage. Not heated, but perhaps a little more mild than outside.

I only really know about my own batteries. There's plenty of discussion online about suggested minimum SOC. Some people set it lower. My inverter has default values for PylonTechs and that's what I've left it at. For me, battery longevity is vastly more important than using those extra few % at the bottom.

At those prices indeed he would save pennies

Edit not sure if he said specifically usage was 15kwh though I just plucked that, the closer to the battery capacity the better of course.

 

[benbird7]

Hi all, some good reading here and been following for a while.

With an approx. usage of 6000kWh back in late sept I placed an order and deposit for the following which was £14.5k from a local reputable installer.

13 x JA 395w Mono Black (5.1kWh total)
1 x 3.68kW Huawei Hybrid Battery Ready Inverter
1 x 10kW Huawei Battery Storage System
1 x Galvanised Bird Protection.
13 x Huawei Optimisers
Set up of Free Remote Monitoring.
Tile Roof Mount System
MCS Certificate
Metering Equipment
Test & Commissioning G98/G99
Scaffolding

I've since removed the inverters as couldn't get stock and I don't get shading on my roof other than a chimney very late in the day. With the removal of them they have now given me an install date now confirmed end of March.

Configuration will be as below, no trees and only chalet bungalows behind me so no shading.


I did get them to price for an edimax for hot water but I like the idea of the boiler kicking in just to heat the cylinder to avoid it not firing up in the autumn. I'm also considering a couple of oil filled rads during the spring autumn.

I've checked my usage since having a smets2 meter fitted back in August and from Oct to Jan I'm averaging 12.5kwh from 16:00-8:00 the next day. I have a hybrid car (10.5kw) battery but this typically needs a half charge after back from work. Normally day usage is minimal as both at work (maybe 2-3kw).

Given my average usage during the darker months should I be looking to up the battery to 15kwh? It would be circa another 3k for the additional module.

I'm thinking even if I can't generate the pv to get it full with octopus flux could use it to store juice at the lower rate to either use the next day or feed back at the higher rate (but don't want to have to monitoring this regularly). Also thinking with that size battery will the invertor need to be bigger to top up in the 3hr window.

Either that or leave everything as it is and see how I get on (but wouldn't get the vat off battery at a later date). Originally I had it with one 5kWh battery module and upped it to 10.

I should also add we have our lazy spa which I'm hoping to get set up around April and use some of the spare PV during the day to heat this but only until late Sept.

Cheers.

 

[Mercenary Keyboard Warrior]

Hi all, some good reading here and been following for a while.

Back in late sept I placed an order and deposit for the following which was £14.5k from a local reputable installer.

13 x JA 395w Mono Black (5.1kWh total)
1 x 3.68kW Huawei Hybrid Battery Ready Inverter
1 x 10kW Huawei Battery Storage System
1 x Galvanised Bird Protection.
13 x Huawei Optimisers
Set up of Free Remote Monitoring.
Tile Roof Mount System
MCS Certificate
Metering Equipment
Test & Commissioning G98/G99
Scaffolding

I've since removed the inverters as couldn't get stock and I don't get shading on my roof other than a chimney very late in the day. With the removal of them they have now given me an install date now confirmed end of March.

Configuration will be as below, no trees and only chalet bungalows behind me so no shading.


I've checked my usage since having a smets2 meter fitted back in August and from Oct to Jan I'm averaging 12.5kwh from 16:00-8:00 the next day. I have a hybrid car (10.5kw) battery but this typically needs a half charge after back from work. Normally day usage is minimal as both at work (maybe 2-3kw).

Given my average usage during the darker months should I be looking to up the battery to 15kwh? It would be circa another 3k for the additional module.

I'm thinking even if I can't generate the pv to get it full with octopus flux could use it to store juice at the lower rate to either use the next day or feed back at the higher rate (but don't want to have to monitoring this regularly). Also thinking with that size battery will the invertor need to be bigger to top up in the 3hr window.

Either that or leave everything as it is and see how I get on (but wouldn't get the vat off battery at a later date). Originally I had it with one 5kWh battery module and upped it to 10.

Cheers.

As you have a hybrid, Octopus Go would likely be better. Not much, but better

10kwh is probably enough, that extra 5kwh might not do much extra work.

I was similar to you, 14x 405s. 12.3 kwh battery but with 90% usable (and its underperforming now, diff story). Daily usage around 21 this time of year.
Already this time of year getting days where battery is full at 5pm and goes through to next day so only using cheap / free units.
Right now I still charge to 100% up to 4:30am, and batteries are often at 40% still at that point.

 

[Dunk05]

Morning,
Got my install at last yesterday. Nice neat install. Tidy as expected but I've had experience of some rough ( as in careless ) sparks recently. 5.3Kw PV and 9.9Kw battery. Started the morning with 100w at about half seven, an hour later we're on 2.4Kw which seems good for a February morning ( clear skies here, yesterday PM was ~300w with grey skies ) Free* power