Game Design, Programming and running a one-man games business…

Why the discovery of behavioral economics means you need to uninstall tiktok.

I studied pure economics at the London School Of Economics. At least, thats what I tell people when I am trying to sound clever. Technically its a true statement. What I tend to leave out, is that I pretty much lost interest in the topic after year one, and was mostly coasting in years 2 and 3. I went to the pub a LOT, I drunk a LOT of vodka and whiskey. I played the guitar a lot, I listened to a lot of heavy metal. This was all unexpected, because I was super-good at economics A-level, and was destined to be good at degree level. The problem? I suddenly realised I found economics beyond a certain level boring, and too maths-focused.

Annoyingly, the solution to my interest-failure would soon be at hand, because 2 clever people eventually discovered an entirely new field of economics called behavioral economics, which, to my mind, was 1000% more interesting, and absolutely was the sort of thing I would be interested in, had it been an option. But no, the LSE still taught ‘classical’ economics, which focuses on interest rates. Other things matter, but you would be amazed how much of classical macroeconomics is focused on interest rates. I studied it for 3 years. I still don’t know whether rates should go up or down. This stuff is complex as fuck.

Why are you reading this?

The significant thing here is how those clever people suddenly were motivated to invent behavioral economics. I’ll give you the short version, and tie it in to the title soon. Are you excited?

Classical economics models rational behavior. In classical economics, every ‘agent’ in the system has perfect information and is perfectly rational. All data is available, and all decisions make sense. If offered 2 products, an agent will evaluate all of the properties of each of these products, giving this decision their 100% attention. They then make an absolutely perfect choice, based on the cost/benefit analysis of each choice. There is no regret in classical economics, no buyers remorse.

Classical economists were not idiots. They were extremely clever people, and they knew that is not entirely how people work, and that we all make the odd silly decision, but at the macro level, across large populations, its pretty clear that rationality wins out. The best product, taking into account the best offer in terms of features/price will always win. In the long run, rationality rules.

These economists were at a dinner party (presumably where they would while away an evening arguing about interest rates), and the host was cooking the main course, while the guests enjoyed some small nibbles. The guests were enjoying the nibbles, and suddenly one of them concluded, with the agreement of all present, that they should ‘put these nibbles away so we stop eating them’, presumably because they were concerned they might spoil their appetite for the main course.

So far, so middle class dinner party.

But hold on. One of these clever economists suddenly pointed out that this was irrational. At the moment, everyone present has a choice: Eat a nibble, or wait for the main course. This was a simple choice between instant satisfaction or a potentially better option if they wait. They were all adults, they could all make that decision. But WAIT. Everyone agreed that in fact, they would be better off if this choice was removed. They would actually be better off with LESS choice.

On the surface of it, this is not exactly earth shattering, but actually, its a revelation. In the word of classical economics, more choice is ALWAYS good. The idea that en-masse, intelligent adults with full knowledge of the available choices, would be better off if they removed some choice, is a complete refutation of everything that classical economics tells us about the world. It was the beginning of an entirely new science of behavioral economics, which would make its inventors widely read, respected and famous, and change economics forever. It would lead to studies of the special nature of ‘free’ as a magical price, and a staggering amount of research and publication. Behavioral economics is awesome.

Ok, but so what?

What this massive upheaval of literally hundreds of years of analysis shows us, is that human beings are incredibly irrational. We are extremely good at backwards-justification, where we pretend our choices make sense, but if you actually look at how we make decisions its an absolute car-crash. We are massively irrational, and so far from the happiness-maximizing creatures that classical economists imagined. Even given really, really simple choices such as ‘eat these nibbles now… or more of the main course in 15 minutes’, our brains completely and utterly collapse with the stress. Only PHYSICALLY removing the nibbles from our immediate vicinity enables us to make what we think is the ‘correct’ choice.

Social media is the nibbles.

You probably spotted that early. I’m not Agatha Christie here, but I hope the point rings true. Deep down, we are all aware that the amount of time we spend doom-scrolling on twitter is not maximizing our happiness. We know that having twitter and tiktok on our phones is just leading us to waste endless time getting into arguments, or just mindlessly scrolling for a tiny tiny serotonin hit…

About two years ago I uninstalled twitter from my phone. I also don’t have a facebook or reddit app on there. I’ve never used tiktok or instagram. A few years before that I quit an online community that just sucked me into arguments and flamewars. I was aware for a good time that these things were ‘bad’ for my mental health, but they were the tray of nibbles in front of me, so I kept nibbling.

I still have a twitter account, but the fact that I have to go to a laptop or desktop PC to use it means I’m wasting less time there. This is, for me at least, a good thing. I know a bunch of people who tweet at least 50 times a day, always political, always angry, always distressed. This is *not good*.

The best economists in the world went decades without realizing just how irrational we are, and just how out-of-touch their model of human behavior was. We are THAT delusional about our ability to make choices in our healthy interest. Its incredibly hard to take this lesson to heart and actually do something about it, but once you do it, its pretty amazing.

You should delete all the social media apps from your phone.

2022: A year spent trying to build a solar farm

The year is almost over, so I thought I would recap. For those unaware, as a side-project (yes its a big side project), I started an energy company called Positech Energy, and decided to build a solar farm. This is an epic tale of frustration and expense, that seems to be endless,, but here is what happened during 2022 for this project!

The first blog update of the year was this one, where I talked about the solar panels. I ordered them way in advance, before we actually had planning permission, because I was hoping to slap them in during summer of this year and start generating actual income. This proved to be both a mistake, and a genius move, depending on your POV.

This was during a time of climate emergency, a global supply chain collapse, and pandemic shutdowns, so it was obvious that lead times on panels would be long, so I ordered them anyway. That means I ended up with over 3,000 410 watt QCells solar panels. They did show up! But by the time we got them… we had no planning permission because it got refused. Oh dear…

I initially decided to forget the whole enterprise at that point, and was quite depressed about it. I tried phoning round wholesalers to sell my panels before they even hit the UK but basically got nowhere. I think people can tell you need to shift them, and offered me a pretty bad price. The company that is managing the project for me did offer to buy them off me at the price I paid, as and when they needed more panels. This was good, and put a floor under my losses, but the trouble is all 70 tons of panels needed storing…

To date I have paid out £15,000 in storage costs for these solar panels. Yup, I PAID £15,000 to keep SOLAR panels in a warehouse during summer. However annoying that sounds to you, it sounds worse to me, but there was no other option. Its still costing me about £600 a week to do this…

Luckily, the price of those panels went up, and I am currently still ahead of the game on this. Assuming they get taken out of storage on schedule (hopefully April), I wont have actually lost out anything except the transport costs for the panels to the site. (Originally that was included, but they needed to be left at a port warehouse instead.

So what else happened?

Well hey we WON planning permission in October, which was a very stressful process, not to mention expensive. In fact the whole process has so far cost me £541,568.94, including buying the panels themselves. Yes, this is a stupid amount of money.

The rough breakdown is:

£50,000 grid connection deposit

£424,000 solar panels

£6,795 for pull-out tests to pick the ground mount system

£3,750 in rent to the farmer for the field so far

..and the rest is planning application and legal bullshit.

Of course the good news is that once you have planning permission…you have it. We cannot get blocked now. The ONLY things standing between us and total conquest of the galaxy is the grid connection and the actual build-out of the site. That means waiting for decent weather, because its in a muddy field near the English/Welsh border, and frankly taking dozens of trucks up a single track lane on very hilly ground when its raining would be a nightmare. Luckily, the UK is so situated that solar output at this time of year is farcically low anyway, so its actually no massive loss.

So where are we left? We are hopefully about a week away from a final, committed quote for the build-out of the farm, and then at that point, the developer will buy the ground mount kit, and order the inverters and other electrical stuff, like the substation. Apparently the first thing that will happen will be putting up a ‘deer fence’ around the whole site as security. Eventually we will have either real or fake CCTV cameras, depending what insurers say.

The aim is to get building in April-ish time. We have mentioned MANY TIMES to the DNO that will put in our grid connection that we really, really want to get connected this year, in Q1 or Q2 if at all possible. These is no free-market for this, and its basically a state-granted private monopoly that does what it likes, so we just have to grin and put up with this.

Also, the cost of the grid connection is likely to go up even more, which is insane. For the love of god, can we nationalize this bit of the grid, and just pay the army to go round the country doing grid upgrades as an urgent matter of national security?

Anyway… a mixed year because we DID get planning permission, but there has not been any real progress on the physical build. I’ll feel a bit more optimistic once I actually see people on site putting up a deer fence. I’ll fill much more optimistic when we see the mounting kit installed and work starts on the grid connection.

Hopefully next years update will be full of amazing progress!

My experience of having a 9.5kwh home battery in the UK for about a month

Recently, we got a 9.5kwh givenergy battery fitted in our cellar. I was very excited about it, and keen to dive into the stats, and wrote a blog post about it here.

I’ve now had it for about a month and thought it was worth typing up the inevitable impressions having got used to the thing! So here goes…

First, some context. This is in a 2.5 bedroom (attic doesn’t count really) detached house, thats very old (pre napoleonic), but has been insulated to the best of our ability. 2 people working from home, in the southwest UK. Also be aware that this was during November/December, and a pretty cold December. As I type this, there is snow everywhere…

I had some initial confusion when the battery was first set up. Day 1, they calibrate it, by basically filling it with grid energy and then discharging it, which feels horrible when you see the first thing your battery does is suck up some prime-time expensive power! Luckily this is a one off thing :D. Once that first day is out of the way, you can then choose your settings and.. to be honest then completely forget about it! My settings, because I have cheap power (75% off!) from 12.30am – 4,30am, is for the battery to fill to 96% during that time and then be in ‘eco mode’ for the rest of each day.

GivEnergy’s eco mode is basically a maximise self-consumption, minimize grid import system. So if you have solar panels, and are producing more power than you are using (fat chance for here in December), the excess gets diverted into the battery. Any power load during the day gets sourced from the battery, so you see the battery state of charge slowly trickle down through the day as its used to power the house:

On the far left is the battery filling up (purple below the line) and my car charging. Combined, the battery charge and car charger hit 9,000w! You will see a few spikes during the day which are basically kettles and coffee machines, and cooking. It looks like breakfast was a big spike load on the grid! and then later mini spikes (below 3,000w) are handled entirely by the battery, slowly draining down to about 8% by midnight. That sustained power draw from 4pm-6pm is a gaming PC and huge monitor playing battlefield V :D.

The thing is… once you have watched these charts a few times, you kind of get the hang of it, and then never really need to look at them, or go near the battery ever again. Its just a magic box somewhere in your house that cuts your energy bill by 75%. The only tweak I have made is that now its even colder, and we are cooking more and for longer, I’ve adjusted it to fill to 96% instead of my original 90%, because we need a bit more energy each day (and if I can possibly avoid any prime-time energy consumption…I will!).

So this is all very well, but what have I learned that might be relevant for people who are considering installing a battery?

Firstly, you really need to get the size of the battery right. I kind of lucked-out a bit, and ended up with the perfect size, but nearly didn’t. At one point, we were going to get an 8.2kwh battery, then a 9.5kwh, then maybe 2x 9.5kwh ones, and even had a board installed on the cellar wall to support a 2nd one, but we ended up with a single 9.5kwh which feels right. Obviously, when you think about it, all you need to do is check your energy bill for how many kwh you use on average each day… and thats the size of the battery you want!

Its a bit more complex if you have solar, because if you have a decent solar array, there may be days where you are generating more than your daily usage, and want to store some in case its cloudy/raining the next day, to maximise your usage. Remember, the goal is to NEVER export any energy to the grid, because they pay you a pittance. So there are circumstances where you might need to oversize things…

For example, if your daily usage is 10kwh, but your solar array in June/July regularly produces 20kwh, then you will be using 10kwh, and sticking 10kwh in the battery for tomorrow. If you dips in solar power are fairly sparse, you will be often faced with surplus solar power and a full battery. IF you have an electric car too, and are bothered enough to trickle-charge it with the excess, then you can of course do this. There are setups and systems that can automate this BTW, that involve cables running to the EV charger from your battery/inverter, but I found it to be prohibitively complex, especially with our EV charger about 100ft from the fuse box.

I reckon for the vast majority of people, whether you have solar or not, you probably should stick to a simple format of just buying a battery that can hold 100-150% of your average daily usage. Its not like you can precisely pick a size anyway, as our options were basically 8.2kwh or 9.5kwh or some multiple.

Something that IS worth paying attention to is the inverter. You need an inverter coupled with your battery, or batteries. Its the thing that converts the stored power (DC) back to AC so the house appliances can use it. We have a first generation GivEnergy inverter, that runs at 3kw, and the ones run at 5kw. If at all possible get the higher output one. Get the highest output inverter you can. Why is this?

Its important to understand the difference between kw (kilowatts, thousands of watts) and kwh (kilowatt hours). The first is a measurement of power as in, the amount of oomph that is running down a cable to a thing, and the second is a measurement of stored energy, ie: the amount of oomph multiplied by how many hours you can provide it, before you run out. Or think of kw as your salary and kwh as your savings :D,

In my case, we have a 9.5kwh battery, fed by a 3kwh inverter. That means that even if the battery is FULL, if I plug in some theoretical device that wants to draw power at 9,000 watts… the battery can only squeeze out 3,000. The rest will get imported from the grid. Why does this matter? It matters because British homes have kettles! and also sometimes electric heaters! In an ideal world your day to day current draw will never exceed the power of your inverter. Every time it does, you will draw the excess from the grid.

With something like charging an EV, you need to just admit defeat. Most EV chargers at home are about 7kw, and you are not going to power your home AND an EV charger with a simple domestic battery and inverter. You need to schedule any EV charging for off peak anyway. The real culprits for going over 3kw are stuff like a kettle, a power-shower, or multiple induction hobs going at once. You might think 3,000 watts is a lot, but boil the kettle and fry some bacon while someone is in the shower and you zip right over that, no problem.

So… I’d suggest a 5kw or better inverter, and probably a 9.5kwh battery, or if you use slightly more energy than me, maybe a 13.5kwh Tesla powerwall. If you have a 4 bedroom house and power-hungry kids, and can afford it, maybe you have a good case for getting 2 9.5kwh givenergy’s or 2 powerwalls, especially if you also have solar.

So there ya go. I’m a total home-battery geek, and look at my stats every day, but if you arent that into it, but just want cheap electricity, then you can just go for it, set it up once, and then never look at it again! Ours is in the cellar and I only even see it if I go down to the cellar to get something out of the freezer :D. Batteries come with apps that will soon ping you if there is an error, so you can comfortably just ignore them.

I worked out on the basis of our first month that payback time for us was 5.7 years. That will fall a LOT in march when our fixed price tariff comes to an end, and fall AGAIN in summer when we get the advantage of saving up our surplus solar power during the day. (At the moment the only financial benefit for us is to buy cheap power overnight and use it during the day). I think in the long run the payback time for us will be maybe 3-3.5 years. Thats crazy good.

PLUS! We did it as a retrofit to existing solar. Right now the govt charges zero VAT on new solar, and batteries can be included, so if you can get solar+battery right now, its an even better deal. I highly recommend it!

Inertia scaling in Democracy 4 (new feature)

I recently added some code to Democracy 4 which introduces a new configurable option for people who are really into the game. This is not ‘live’ yet but will be in the next update. I have not totally settled on a name for it yet, but I think I’ll call it something like ‘opinion inertia boost’, because that ties in with other uses of the term throughout the game. So what is it?

Inertia already exists in the game. Every effect that a policy, an event, a dilemma choice or anything else may have on anything can have some inertia applied to it. This means that instead of X affecting Y, and it being a simple equation, in fact its an equation that takes the average value of X over a certain number of turns, which is an integer called ‘inertia’. You can see the value of inertia at the far right of any of the indicators in the game that show an effect:

The inertia is a value set by me, or by a modder, and its fixed. Its basically part of the equation, and set in stone. There has not yet been any way to change this by the player or during the game.

Inertia plays a vital role in making the game both realistic and fun. In practice, if you introduce grants for business startups, it does not convert 500,000 citizens to become capitalists the next day. The impact is going to take years. people need to hear about the grants, apply for them, see their business do well, tell their friends, people have to read newspaper stories about this happening… and perhaps even more relevantly, people who were once socialists but get ‘converted’ to capitalism have to slowly get out of the habits of their previous views, and adopt new ones, even in opposition to their friends/family and peers.

I see this sort of thing happen quite a lot, and have witnessed it with both friends and relatives. When peoples circumstances change, they tend to continue to cling to their existing core beliefs and principles, but over a period of time, opinions will change. With weakly held opinions, its quick to change, but with deeply ingrained beliefs, especially those that come from family, change can take a very long time.

I’m an example of this myself. I grew up in a very working class circumstance. My mother was a trade union representative at work, where she worked as a filing clerk for a trade union HQ (different union!) so she was Trade Unionist to the power of two! My father was also a union rep. We went on exciting day trips to the labour party conference. I read the communist manifesto, and Das Kapital as a teenager.

Fast forward thirty five years and I am a director of two companies, who trades on the stock market, and has employed people and run a multinational company (albeit v small). I’ve even worked on stock market trading floors. I own a single book by Ayn Rand (which I thought was interesting, albeit pretty ranty and very repetitive). My views have definitely changed over time, and with changes in circumstances.

The point is… change of core beliefs takes time. We all think we would keep the same principles until death, but thats unlikely. Societal change is very real. You might think your views regarding being liberal/conservative or left/right are very deeply held sensible views you independently arrived at, but this is very unlikely. I thought I was right as a teenage communist.

So the big question is… how long does it take for politics and society to convert someone from being hard right to hard left, or liberal to conservative? I have no definitive answer, but its a long time. Democracy 4 limits all inertia to a maximum value of 32, for technical reasons, which is 8 years. probably not long enough…

Like all games, Democracy 4 has to balance fun with realism. Not many games have a core mechanic of it taking 32 turns for you to see the impact of your choices, especially not if you can lose the game in an election in maybe 16 turns. Thats pretty brutal. Not only does this make the game hard, it also makes it frustrating. If inertia is too high, many players will just think ‘the game is random’ and complain about the RNG. Ironically there are very very few random numbers in the game…

Plus many players will not bother reading the tutorial or looking at the tooltips. I bet a good 30% of the people who play the game don’t even know inertia is a thing, or where to find it. Most players don’t really know what they are doing, because people have 1,000 games and no time to devote to learning the intricacies. If I modelled inertia realistically, a lot of frustrated players would have no fun.

…and yet…

There are definitely players who feel that they would prefer realism over ‘simple fun’. These players are frustrated that real societal change feels so easy in the game. If they want to convert France to a Capitalist state, they WANT to have to really struggle to take its left leaning population slowly along for the ride. They WANT change to be slow, and take longer, which is why I am adding this cool little slider to the games option screen:

This slider defaults to zero, where it has no impact, and goes as high as to add a 3x modifier. At the far right it will triple the inertia values for all inputs to socialism and liberalism. This will make all policies and events and dilemma choices act more slowly on the membership of these voter groups. (One value affects membership for both socialism and capitalism, on a spectrum and the same for liberal/conservative).

I’ve written all the code, and tested it works on both new games and save games. Everything seems fine but I will do a bunch of playthroughs before I do a new update that includes this slider. I’m pretty sure that 95% of players will never experiment with it at all, but I have enough players that I think its worth adding it all the same. It definitely gives me an easy answer to anybody who comments at me telling me that this part of the game is unrealistic!

Note that this difficulty in changing the country’s views is very much a real world modern problem. Even if Joe Biden was a communist, there is no way he can convert the majority of the US electorate over to his views in a single term. Arguably all Obama managed to do, in his entire tenure, is to get the affordable health care act in place, and it comes nowhere close to being a state health service like the NHS in the UK. Even a popular US president, with control of the house & senate, has to move extremely slowly in changing what the acceptable size of the state is, or changing social policy.

Trump found it almost impossible to actually build a wall, Obama found it impossible to close Guantanamo. Blair did very little in terms of raising taxes, Thatcher did very little in lowering them. Change takes real time.

One final thing: This slider only affects liberal/conservative and socialist/capitalist. I am unsure whether it should also affect membership of the religious group. Opinions very much welcome. I don’t think it should affect most groups, as peoples membership of these is a lot more fickle and easily swayed.

I finally have a home battery!

At long last, its finally installed and actually working, and after a very long and very tedious process that I will not bore you with (much) my house now has a 9.5kwh home battery connected up and working in the cellar. Its actually powering everything in my house right now, and is super cool.

This has been a long process because just when I started to ask a company to install one, UK electricity prices went absolutely insane, and everyone and their dog suddenly wanted a home battery installation. Getting a Tesla powerwall would have meant possibly an even longer wait, and to be honest, they were quite pricey compared with what I eventually chose (a Givenergy 9.5kwh one), but even when I found an installer, and agreed to have a battery installed, there were endless delays. Initially I was going to have a 9.5kwh (latest model) battery, then it became obvious they were hugely delayed, so opted for a single 8.4kwh one, then at the very last minute it turned out a 9.5kwh one was available, and as this was the latest tech, that allowed 100% depth of discharge and unlimited cycles (basically you can fully fill/empty the battery whenever you like without affecting the warranty), so we went with that.

Getting people to come around and install the battery was one thing. Getting it actually finished was another. The installation has been a real pain, but TBH that seems to be mostly down to huge demand and chaos among all the companies doing this sort of thing right now. We had the battery installed, but dormant for about 4 weeks until a vital missing component showed up (a wifi dongle that allowed it to talk to my home network, and thus back home to the battery management system run by the battery company).

Now its all installed, it all feels like it sort of went ok though, because my ideal scenario was to put it in our cellar, which is damp, and dark and empty, and thus the perfect location. Why take up room in the house with a great big metal box when you are almost never going to have to physically go see it? I had worried that the installers would be negative about anything ‘non-standard’, but were happy to run the power cable from our kitchen fuse box outside the house, along a wall, then down through a hole into the cellar and the battery. I’m very happy with where it is:

When it was installed I asked them to set up a double size wooden board on the wall and allow space for a second similar size battery if I wanted to add another one at some stage. In practice, I doubt this will happen. The picture shows the battery (at the bottom) and above it is the inverter. Basically an inverter converts DC to AC or vice versa. This battery is ‘AC-coupled’ which means its on the ‘house’ side of the setup, and is wired in to the fusebox pretty much like anything else. It needs the inverter to convert that AC power so it can be stored in, or sucked out of the battery itself. On the plus side, if I got a 2nd battery, I don’t need another inverter, as you can just daisy-chain em. The red switch is an emergency cut-off.

Back upstairs in fusebox land, you end up with an extra widget called an EM115 that takes up one fuse slot. Its a fancy management thing that seems to be required to check everything works:

Connected to this widget is something called a CT clamp. This is a thing that wraps around a cable and tries to detect the power load going through it, and the direction of it. I already have one, used by my car charger in the garage, to ensure the charger never overloads the house grid connection. This new one is connected to the EM115 and the battery so the battery can tell whats happening with my grid connection:

This information is important because the battery uses it to do cool stuff. For example, you can say to the battery ‘Try to never export power to the grid!’, and then on a day where the solar power is high, and your consumption low, the CT clamp tells the battery that we seem to have a negative power flow (exporting to the grid) of X watts, and it therefore tells the battery to soak up X watts of power to balance it out and ensure any ‘surplus’ solar is kept in my house and not given for free to the evil energy supplier!

Whether or not this is what you want your battery to do is dependent on your circumstances. We got our solar panels 12 years ago on an early ‘feed-in-tariff‘. This means that we get credited a nice amount of money for each kwh of power our solar generates, regardless what happens to it, and we get a ‘deemed export’ of 50% of that. This means if our panels generate 10kwh, we get paid 10xFIT plus an extra 5xExportTariff. The actual export tariff is super low, so it wouldn’t be a good deal anyway, but as our tariff doesn’t measure the actual real export, we are kinda gaming the system a bit there by trying not to do any :D

For people with newer solar panels, they may actually have an export meter, and genuinely be paid per kwh they export. So why would you not do this? Because the very very best rates you get to export are insulting. I’ve seen a high of £0.07/kwh which is an insult considering that companies SELL you the same power for £0.24/kwh… Thus even if you do have an export meter, it makes more sense to keep that power in your home and use it later rather than sell it, then buy it back at a huge loss…

For people with normal jobs this is even more acute. In the UK summer your home solar will generate tons of power while you are out at work, which it sells for £0.07 for you to buy back in the evening to run your home at a huge loss. Sod that!

But enough about the economics! lets look at the real reason anybody gets a home battery – fun charts to look at:

This is one of the many views you get from the givenergy website. It also has app for your phone, obviously. This is my first day with the battery, and I screwed a lot of stuff up which I will explain. As part of its first-run ‘calibration’, the battery gets filled to 100% from the grid. Thus it was at about 80% full around midnight. I had then stupidly told it to fill to 100% between 00.30 and 4.00AM which is when my electricity is 75% off. It did this (see the top purple line going up to 100%) by importing that power from the grid. Thats the red section below the base line on the left, and the purple is it filling the battery

The red is a bit higher than the purple (well…below…) because I also needed *some* power to run the house even overnight.

I had screwed up twice because I’d told the battery to only discharge from 4.00am onwards, so between about 1.30-4am you can see those red downward spikes showing me importing power to deal with our energy demand (green upwards). Then from about 4am onwards, that disappears and we are running entirely from the battery since then (including now). Thus the battery level is slowly running down (top purple line).

The UX of the app is not amazing, hence my screwups, but I think I’m getting the hang of it now. You can see on the RHS of the chart some downwards purple and some upwards yellow. Yellow is the output of our solar panels, and for a period there it exceeded our energy usage, so the excess was dumped back into the battery. Working as intended!

You also get real time data like this:

This sort of thing can drive someone insane, because very often the numbers do not match up exactly, and you start to wonder if everything is broken. It isn’t, but you have to get your head around two concepts:

Firstly, the accuracy is not perfect. We do not have an export meter, so we are relying on some pretty rough measurements of power flows being detected by a loosely attached metal clamp on a cable. Thus you have to allow for a bit of a fuzz factor.

Secondly, the battery response is not instant, but has a slight lag. This is REALLY important, and can cause confusion. For example, say you are consuming 200w of power, and the battery is happily supplying 200w from power you saved up earlier. All is good. Then suddenly you switch a 2,000w kettle on. That power HAS to come immediately, and the battery is not set to do it, so for a few seconds, the extra 2,000w comes from the grid. The clamp detects this, tells the battery, and the battery ramps up to output 2,200w instead. Kettle finishes boiling, but the battery is still at 2,200w. The excess automatically flows to the grid. The clamp then detects that, the battery is told, and ramps down to 200w again.

That all sounds ok, but what it means is we briefly imported 2,000w from the grid, and then later briefly exported 2,000w as well. In the grand scheme of energy flows, its a minor deviation, but that is why there is not a perfectly flat line between 4am and now, with zero grid import or export. The import/export is VERY low compared to normal, but it still does happen.

If you have a smart meter in-home-display you will already be fairly familiar with this. In theory your TV will use maybe 200w for example, but you only need a helicopter to explode in an action movie, with a big loudspeaker-driving bang, followed by a loudspeaker-minimal silence, to see that the per-second power draw of almost everything is very, very variable.

I guess this is early home battery technology. Maybe eventually this sort of thing will be somehow perfect with sub-second response times. Maybe thats really hard on some components and electrically tricky. I don’t know, I’m just some guy with a battery in his cellar.

ONE MORE THING

You *can* wire a battery to be a backup situation if your home loses power due to a cut. We did not do this. Initially I had been told this could be done. I was then told that it can only be done for certain circuits in the house. I was THEN told it means adding yet another fusebox, at which point I bailed. Our kitchen already looks like a nuclear power control room.

One of the undiscussed issues with home battery as backup power is that the actual output RATE from a battery is quite low, in this case 3KW. 3KW is a lot, until you have a router, 3 wireless boosters, a TV, streaming stick, home theater unit and a subwoofer plugged in… and then turn the kettle on. Basically you run out of headroom, and things will start cutting out. Home batteries are great, and can provide a lot of power, but the big old electricity grid can deliver 100 amps at 230v and thats a lot of juice. If you want to be able to power everything, including kettle + electric cooker and also charge a car and do everything else all at once, you need some serious big-ass inverter, and frankly, powercuts here are rare enough that I decided to just not care.

I will do (inevitably) another post in a week or so, when I have long term data, and the energy bills to prove it. I’m still in the exciting early days of trying to find an excuse to go get something out of the freezer (also in cellar) as an excuse to gawp at my battery…

For those curious, the total installed cost was £5600 plus vat @20% £6720.