I’m dealing with an installer who has been doing Solar for at least 20 years and who has threatened that the 2 batteries will be installed outside. Admittedly, I suggested they go in a store area off a first floor bedroom. This may have been not a good idea. However, I have a small downstairs room almost underneath.
My son-in-law thinks that if there every was a fire it would be impossible to put out. He suggested 2-3 car lengths away to avoid the fire spreading to our house. It comes down to risk management, care and maintenance of the battery. The industry is obviously doing its best to ‘reassure’ the public.
Our Powerwall is inside the garage, against an outside wall.
Managing the temperature of the battery is key to sustaining its safety and durability.
To help with this, the battery is installed inside rather than outside, as this keeps away the coldest of the outside winter cold and the hottest of the summer heat. The Powerwall also has something called “thermal management” in it, which effectively warms the battery once it gets too cold, i.e. getting close to freezing.
To protect against overheating, all decent batteries should have cell management units (CMU) built in to monitor the condition of each cell. Ultimately though, LFP cathodes are less liable to thermal runaway than NMC ones, hence my earlier comment.
Your son is quite correct about thermal runaway though. Once it gets serious enough, you won’t put out any fire as there is enough oxygen in the lithium ion electrolyte to sustain it even in the absence of atmospheric oxygen, i.e. air. However, matters need to have gone drastically wrong for the multiple layers of internal safety to be overcome to the extent that thermal runaway occurs, especially with an LFP cathode battery. At that point, the option of last resort is called for, namely a good home insurance policy!
Despite all of the above, we prefer our battery to be in the garage, rather than the house, with a thermal block fire break wall in between the two. Just in case…
Well after joining Octopus on 21 October 2022 I have a new Octopus compatible smart meter. Why they couldn’t tell me that my previous SM installed in July wasn’t suitable in early November I don’t know. According to the guy who fitted the new SM if you have batteries there are even fewer that work, but mine should do everything!
The solar and battery installation starts next Monday, and the Zappi when they get hold of one. Therefore I have been investigating how to download my half hourly data and happened on the Octopus Energy Watchdog App, which also shows the market tariff at least a day in advance. I can now see that GO is designed to give Octopus a healthy margin at 12p/kWh! Hardly any of the rates at other times in the next period exceed the capped rate! So is Agile a better bet if you can get a day’s worth between 12.30 - 4.30am?
The T&Cs say if you leave you can’t return to these special tariffs within 30 days.
Ive seen a bit of discussion on the Givenergy forum about placing batteries outside. Main risk here is that they dont charge if the battery is below 0 deg C. And our cold snap before xmas found a lot of GE batteries not charging at night. So, whilst they are IP66 rated and can go outside, they may not work. So not helpfull.
Mine is in an integral garage and the lowest ive seen it is 13 deg C.
I keep looking at Agile but think it probably works best when you can flex your charging times according to the pricing.
While this could be done manually I think it probably would be best automated and that would need a fair amount of effort.
At the moment my bills are relatively small so I suspect the effort isn’t worth it, though I may revisit that since I think the outgoing tariff is better with agile and my current Go tariff expires in August and then the off -peak costs becomes significantly more expensive (I expect).
I’ve since looked again at Outgoing Octopus. It can be mixed with Agile but not GO. To be honest if you have enough battery storage you have the flexibility to export at peak times in the summer with Outgoing Agile and charge the car and/or battery overnight if solar is low.
SolarEdge are close to having an improved App that allows the battery side to be user controlled rather than being setup once by the installer. There are videos on YouTube by Antony Dyer showing how to setup seasonal profiles that adapt to the changing needs throughout the year (more so if you have a heat pump). Therefore, the Tesla tariff for PowerWall owners is something that one can do for oneself without Tesla taking a cut. The GO tariff rates give one an idea of what the risk free buy price between 12.30am and 4.30am is to help you decide whether to use Agile instead. If you have battery capacity for a whole day from an overnight charge it hardly matters what the daytime rates are except in a really cold spell.
I only have some of yesterday’s energy figures as that was the day the new Smart Meter was connected. So, on Octopus Agile the Electric would have cost 29.5p/kWh!
Since installation at the end of nov 2022, i have only imported about 5 units of peak rate electricity. My 9.5kWhr battery and panels allow me to charge the battery on Economy 7, then power the house until Economy 7 the next day. Some days have been close, but if i can manage it at this time of the year, the rest shouod be easy.
Today was the furst day my generation was more than i imported via economy 7 last night. And because no-one was home during the day, i exported ( once my battery was topped up) most of it.
If, i could have trusted the weather predictions today, i didnt need to charge the battery much last night, instead allowing the panels to charge it.
A bit risky in January in the UK though.
So, I have changed my switch to Agile Octopus. Looking at the half hourly figures it is apparent that the rates are also capped at 33.73p/kWh. In the detail it is apparent that the government provides up to 18p/kWh subsidy. Therefore, if the Agile rate went above 33.73 + 18 it would exceed 33.73p, but in a window it would be flat. With Agile I can also have Outgoing Octopus. Long May it stay like this.
I take it you are an agile outgoing octopus rather than fixed?
Does your inverter/battery system automatically get fed the correct times to import/export to octopus?
The Solar, 20kWh of battery, and a Zappi get installed next week. Not likely to export much at present. Apart from sub zero temperatures we get by on up to 25kWhs/day including the Air Source Heat Pump.
I expect the ASHP demand to gradually drop to water only by April when I think I need to start discharging the batteries down to 50% to the grid at peak times. So Outgoing Octopus Agile.
Apologies if this is deemed a bit off topic - but just looked at what the wind turbine generated since the last reading - 2000 kWh in 19 days, of which 1000 was in the last 7 days. We only get one third of that but been happily charging my wife’s car for nowt at the slowest possible speed (1.4 kW) overnight whisky also running the house (probably - don’t have the measuring equipment to check in detail)
These are important considerations for building regs and home insurance, in my opinion.
Obviously for rooms over/next to garages the regs require a firewall between, and where doors are fitted, sealed against ingress of fumes. In terms of dealing with battery failures in garages, would the regs require an upgrade?
It will be interesting to see if the regs. show signs of evolution to deal with home battery storage over the next 10 years?
The installer was happy with a gable wall (chalet style) away from windows and at least 1m away from the now redundant gas supply (meter removed). Still planning on the detached garage, either inside or outside (with a shed round it).
Impressive number of units in that period of time. But no surprise if where you live is windy. Key is to have domewhere to use/store those units for when it’s not windy. I hate selling my excess solar back once my battery is full.
It’s completely uneconomic to try to store all the excess. Our daily share of the max ever generation (about 210 in a day with 11kW generation the theoretical max is 264 kWh in a day but not seen more than 220. If it gusts too much the wind turbine shuts down) is about 70kWh but I can’t see us getting more than 20kWh battery. Hoping to get solar and battery later this year
The wind generation is I think more peaky than solar. We can go 7 days and generate zero from the turbine
Hello Tim, How much does your 11kW turbine generate in a year? I was thinking of a 1kW Greef Vertical Axis turbine. I need planning permission as I already have an Air Source Heat Pump🙁.
It varies quite a lot - the worst year (2021) was a bit under 19,000 and the best year (2020) was nearly 28,000. We have had a total of 265,000 kWh in 11.5 years, so the overall average is 23,000 pa. The big problem is turbulence - that kills production and so you may not do proportionally as well, but I have no experience of anything other than our own turbine
