Has anyone had a battery added to a pre-existing solar panel set-up?

[JustAMiddleAgedDirtBagBaby]

We have solar panels on our house. Because of the way it's set up we don't have a battery and if there is a power cut we can't use power from the panels even if there is enough sunlight to generate.

I looked into having a battery added a few years ago but we were quoted insane prices, more than the whole system had cost initially.

I really want to explore this again as it feels bonkers to be able to generate power but not use it when we need it.

Is this just a wildly expensive thing to do, or did we just get weird quotes last time around somehow?

The company who fitted the system is no longer in existence I think, or they would be my first port of call.

Following

Hm, not sure when people are around in this corner of mumsnet, but giving this a hopeful bump.

My parents did last year, I'll try to find out some info from them.

We did earlier this year (having put in an array of panels about 4 years earlier). We'd got an EV and a heat pump since getting the panels, so it seemed sensible to get a battery as well!

From memory, I think it cost about £3k - not sure how that compares with your quotes? We did a lot of modelling (taking into account the fact that we charge the car on the cheap rate at night, and also that we currently sell back excess generation to the grid that now goes into the battery) to decide whether it was worth it overall. I think the payback time for us is about 5 or 6 years.

I’ve batteries on my system, likewise I charge them when it’s cheap electric in winter to use during the day.

Thanks for asking this OP, we’re in exactly the same boat, including having looked before and finding prices too high- I think prices are lower than they used to be. We are in the process of getting a quote, and will then do calculations as mentioned by @mackerella. Will let you know how we get on. We’re intending to be in the house for probably another ten years or so, so I think it’ll probably be worth getting the battery.

Following too. Having an absolute nightmare getting paid for the energy my panels produce. Would love to have batteries installed and live off what the panels produce.

@PollyannaWhittier That would be great, if you don't mind!

@Waitingfordoggo Someone quoted us £15000! I can only assume they don't want that work.

When we had the system installed we were coming at it from a green energy standpoint but, living rurally and having a heating system which relies on electricity, if the power goes out in the winter we have no heating. A battery system might go some way to alleviate that.

@notwhingingjuststatingfacts I've no idea how easy it is to switch, but we get our payments via Microtricity, which is part of Ecotricity. I've always found them really good.

We have a battery only, no solar panels, no heat pump. I bought the battery cheap as end of line and I calculated that it would have paid for itself in 2 years and now it has been going for about 3 to 4 years. I have often thought that it would be useful to use the battery when the power goes out but the inverter I have got needs to be able to "see" the frequency of the AC from the grid to work so can not be used when the mains is off. HTH

We did this, about 3/4 years ago. We have had solar panels for about 15 years, but added the battery. We live semi-rurally and do get regular power cuts, so I was thinking along the same lines as you. But as far as I understand (and I am a numpty when it comes to this sort of thing) you can't just switch to battery power if the grid goes down. It's more of a store while everything else is working. I've never had to resort to torch and candles since we have it, so maybe it switches itself (after a blip.....our outside lights start beeping if there is even a slight stop in the supply). It has been great this year as we had a/c put in the sitting room last year and I was getting v worried about the impending bill, until realising (told you I was a numpty) that when it's hot, generally the sun is out and so we are generating. Our system cost about £5000 for the battery alone (including all the connection). We are in Bucks.

Im with BG and they won’t let me switch. I’m locked in with them because of this dispute. I’m being forced to pay more than double for my electric and gas than other providers as a result. It’s been a 3.5 year nightmare and one that has almost cost me my mental health. I’ve stopped paying anything now as I don’t have the money. It’s an utter shitshow but nobody will help me.

I'm so sorry to hear that, what a nightmare.

We have both and as PP said can't run everything off the batteries in a power cut. I think we could maybe add a single circuit with a couple of sockets. I'm not certain of the exact reason but think it's to do with electricity flowing from us to the grid causing safety problems or damage upstream? Don't quote me on that though I'm no expert!

You can do it. You just have to have a big switch installed to turn off the mains power line. So you can’t send power the wrong way up the line. I can understand why the energy companies would be nervous about it though.

So at the farm where we are reliant on electric being constant we have a back up generator in the form of a tractor. When we have a big power outage that’s going to last a few hours or more we switch to the tractor. That involves switching everything off, turning this huge fuck off big switch to disconnect the 3 phase (high voltage mains) and onto the back up. We then turn essentials back on. It’s a bit of a hassle and takes about 15 minutes to do the switch (hence only doing it when absolutely necessary) as we are on 3 phase electric.

It should be simpler to go from regular mains to battery. But would definitely involve some mechanism to shut off the incoming mains lines so you can’t inadvertently back feed the grid.

This is only of partial help to OP, but we had a full solar panel/battery/back-up system installed in one hit nearly a year ago. It cost about £11k for the whole lot; the back-up system was a big part of that (we have only 7 panels).

For us the back up system was really important - it means that if there is a power cut, the solar panels will continue to charge the battery and our whole house will continue to run off the solar panels and/oe battery (obviously subject to the sun and whatever battery charge you have).In practice you’d want to switch off anything non-essential.

There is another, cheaper option which would allow you to have a designated double plug socket (I think!) which would continue to work on the event of a power cut, but that’s all that would work.

In an ideal world/if money were no object I actually think 2 batteries would be best (though I don’t know if this is possible). Because for day to day use the battery charges up and discharges depending on lots of things (price of electricity, demand from the grid, your own household demand). This assumes you’re using automated scheduling for it.

So in theory we could have a battery that’s only 20% charged, and then a power cut happens and we’re not able to make the most of it.

Hence if you had a second battery the system could (in theory) ensure one is always fully charged as back-up. But it would be silly money even if this is an option!

My friends added batteries thinking their system would work when they have a power cut and it doesn't. it's affected by whether or not the infrastructure is up and working, so if there are scheduled power cuts or outages you are still without power. I believe you can go to a standalone system but it is quite expensive.

They're producing smaller batteries in Australia now I believe that are cheaper - I'm waiting for them to come over our way.

We had a battery installed about 10 years after our solar installation was done. All works fine.

We've recently had panels and two batteries installed for around 10k if that helps? I think the batteries were at least half the cost. The problem you have is to use the stored battery power in a power cut you have to have another bit of kit installed so it isolates your supply from the mains to prevent you electrocuting any engineers working on the mains lines. I looked into it and it was an additional £1000 so not worth it for us (we only have a few short blackouts a year).

We had a battery installed with ours when they went in first, but the house doesn’t run off the battery when the grid goes down. There was a complicated explanation about this that went over my head. I’m not sure whether it’s not possible or that it’s just even more ££££.

The battery is great though, we buy and store cheap electricity at night, and charge the cars and during the day the household draws from the solar panels, and battery first. It’s massively reduced our bills.

We installed panels and a Tesla battery in 2018, and it does work in a power cut. You can programme it (I think? Or it has a setting) so that in “storm mode” (which it gets from the Internet automatically) it won’t run down to less than 20% which is kept in reserve; and if there is a cut, the house switches to the battery supply. It’s only happened once or twice and for very short periods (minutes), as we’re in a suburban area that isn’t prone to really bad weather and outages, but it’s definitely worked.
The installer was a company called Joju, they were very good.
Later on we had to get a qualified electrician to fit a smart meter (for some reason Ecotricity, our provider, were slow rolling them out), so we could take advantage of an overnight EV tariff. It was a more complicated job than normal because the current goes both ways and because overnight sometimes very large amounts are going through the cable into the house and straight into the car battery.