I’m thinking of getting solar panels and a battery for our house.
What’s your setup like, and is there anything you wish you’d set up differently if you were going to install it again? What supplier are you with?
A company extremely local to us is offering 12x Aiko Energy panels (465 watt), with a Sunsynk 5 kW inverter and a 5.32kWh battery. Octopus Energy are offering a similar set up for a similar price, but they’re using 450 watt panels, so with using 12 panels I’d be potentially be losing 180 watts vs what the other company is offering. Is that a significant amount or would it basically not really amount to much additional power?
just had ours installed and even today when its cloudy and raining we are producing enough to run the house (low usage). couple of things to be aware of - On a normal system, if the grid goes down you cant use you solar or battery(may not be a problem for you), for this you need a back up box with off grid capability. There will likely be an export limit set by the DNO so the excess may get wasted anyway. 180 watts isnt much, possibly run a fridge on it
On a normal system, if the grid goes down you cant use you solar or battery(may not be a problem for you), for this you need a back up box with off grid capability.
Is this because there’s no way to dump any excess electric back into the grid? I don’t think this is too much of a worry for me though, I don’t recall a power outage in the past 8 years of us living here! touch wood
No - the inverter needs the 50hz signal from the grid AC to work.
If there is nowhere for the energy to go the inverter will lower the output from the panels. I think the main reason is because if they turn off the grid for maintenance, you cant start exporting and potentially kill the workers. There are also other complications like the inverter needing power before it can create power
If I were doing this all again I’d use Victron inverter kit with the self build batteries (Fogstar do a decent kit), for an entirely self hosted control system, and whatever panels fit the roof space best. But 180W is nothing to worry about. More important to find a second area for another array.
Oh, and you will want a hell of a lot more than 5kWh worth of battery storage. I have 14kWh and run low in winter when the panels make naff all (charge on cheap rate power to last all day)
The quote I received from the local company (the 12x 465w) panels has come to £8,500ish, including installation. I might ask to see what it is with a 10kWh battery, and see if it makes sense. I did wonder if 5kWh would be enough throughout the winter, I’d imagine it might be only enough to get through the peak period.
Octopus’s provisional quote was £2k extra although I need to give them more specific information, so that quote might come down.
The way our roof is means we’d basically use all of it and it’s facing east/west which should give us a longer sunlight duration.
Check the quote which should state which battery is supplied, then one of the general suppliers, itstechnology, bimble solar etc.
A battery installation should be zero vat, so a single 4.8kWh US5000 Pylontech battery is like £720 ex vat These are 15 cell batteries and they are essentially plug and play. Some batteries are 16 cell batteries so have a little more power stored but seem to cost a lot more. Can’t mix and match batteries of different numbers of cells.
The batteries should essentially be supplied at cost, there is zero work to install more.
Decent price TBH. Should pay back in 5 to 8 years with the bigger battery and the right tariff (I think the best tariff is Intelligent Octopus Go and the fixed export tariff, ~15p/kWh export, but 7p/kWh cheap rate import, and need an EV)
The battery is a Sunsynk L-Series.
Luckily the whole package is VAT free, apparently that ends in 2027.
They’re partnered with EDF although you don’t have to use EDF. Unfortunately we don’t have an EV yet, and won’t for a while as I’d rather run our current car into the ground!
Yeah I ran my car until the engine light came on and swapped later on. It’s fine, no point trading in unless you can get a good deal IMO.
Personally, I’d ask for a quote with a different battery, that looks to be overpriced compared to others so extending the battery size will be more expensive than it should be.
Solid advice right here.
I have 13.5 kWh battery storage that I charge overnight with cheap electricity if needed. During winter I could do with more storage.
I control charging of the battery (and EV) automatically based on expected solar production the following day, which I estimate using a forecast model I re-train couple of times per week based on latest data. The model uses Met Office weather model forecast for our area as input. Most days it’s accurate to within 1 kWh.
I have 16 LG panels spread so that they produce almost from sunrise to sunset + 5 kW inverter. This has worked really well. There is plenty of power to run air conditioning in the summer and even charge the EV, but winter months are meh. Sunny summer day: 25-30 kWh, winter 1-5 kWh.
I forgot to add that I’m with Octopus Energy. Their Octopus Go plan offers great rate overnight and is not too bad during the day at lest in our area. Their free energy sessions have also been in active use: battery charge, EV charge, immersion heater and sauna stove being on simultaneously does put the house electrical system to a test!
My aim is to use as much of the solar energy I produce myself, so I’m not bothered about exporting energy.
Are batteries ok in the roof? I thought the temperature variation up there would be too much for them?
(Lazy question without searching for the answer myself)
Current guidance does not allow installation in a roof space, and limits capacity to 40kWh in most houses (80 kWh in detached or separate garage). Guidance, not law iirc.
But they are so heavy I would not place them on ceiling joists, I’d want them on a concrete floor
In a similar vein: any good hybrid inverters out there that play nicely with HomeAssistant (e.g. via Modbus or other)?
Is it worth getting 40 year guarantee? Arent most of these businesses going to be out of business when I need them?
Get a larger battery.
By far the lion share if the savings come from internal usage. Export payments are 20% of so of electricity costs, so you want to be using what you generated.
I have a 5.4kW array, and a 8.8kWh battery. 15% of the battery has to be reserved, so actual capacity is lower.
We basically live off grid for 6-7 months, but winter production is so low (aprox 20% of summer ) that it’s hard to even fill up the battery.
But a larger battery would help for those spring and autumn months when some days are good, some are bad.
For reference, comercial installation have a 4:1 ratio of battery capacity to production. In my case that would be 20kWh! Or 5 days of average consumption.
One final thing to say is that our battery system is capped to 3kW. So even when full, if we ask more electricity than that at any point we would be importing.
What this means is that going gas free is harder, as some appliances (hob, kettle) consume a lot.
Time of use tariffs have low import costs than the price Octopus will pay for export, so it’s actually better to export solar production than to self consume, so your first advice is inaccurate.
