A second Tesla Powerwall 2? Or a Powerwall 3 in UK?

[@more.power.]

Thank you Colin this was the first time that I have a better understanding for solar power and it's storage. Cheers

[@lavectech]

Keen for the Powerwall 3 here in Australia for a new install with inverter integrated.

[@video99couk]

Yes the Powerwall 3 makes sense on a new install. I understand that it's now available in the UK so shouldn't be long behind in Oz. Really it's not so much an integrated inverter, as no inverter. The only inverter is on the output side of the battery, just like any other Powerwall. They are deleting the DC from solar to AC and then back to DC for battery charging, which makes a lot of sense. There will still have to be some DC to DC management for battery charging, but that will likely be a high frequency (efficient) system.

[@UpsideDownFork]

Look at the start up voltage across a manufacturer's range of inverter. Typically a 3.6kw and a 8kw inverter now have the same startup voltage. This oversizing seems to be a hangover from 5-10 years ago.

[@video99couk]

My thoughts exactly. I think that solar oversizing (really, undersizing of inverter) is being done for historical reasons. I certainly would have selected a 6kW inverter for our 6.4kWp array with hindsight, rather than 5kW.

[@UpsideDownFork]

Have you considered switching to agile and exporting at 15p?

[@video99couk]

Yes, very much considering that. But I think I may go through one winter first with the two battery setup and decide after that. If I leave Octopus Go, I may not be able to return to it, since we don't have an EV and can't afford one.

[@PVOK232]

Heatable sell the powerwall 2 and 3 cheaper - nice video btw

[@edc1569]

Have a look at tariffs with a longer off peak period, i'm on EON Next Drive and it gives you 7 hours off-peak which is two extra hours to charge, and two extra hours not discharging the battery.

[@video99couk]

Octopus Go has I believe the cheapest off peak rate. It's a case of balancing rate and hours.

[@video99couk]

Octopus Go has added an extra hour of off-peak from 1st July 2024, very welcome.

[@UpsideDownFork]

Have you considered additional panels on your front lower roof?

[@video99couk]

Yes, but the whole lower roof and porch needs rebuilding. It has a small leak and is clad in what looks like asbestos. So we need the budget to rebuild that, and will then include four more panels on that roof.

[@sparkybruce]

I was lucky enough to go for a pair of powerwalls now 2 years ago - though the price has now dropped quite a bit. I did add an extra 5kW of panels to my existing inverter last November which brings me up to a total of 15kW pointing in all 4 directions feeding into my 10kW SolarEdge inverter. All it needs is sun to run though recently all we have been getting is rain :-(

[@video99couk]

There's a lot to be said for having panels point away from South, most especially West, for getting extra solar generation in the evenings when most families need it.

[@dougle03]

Have you spent enough time looking at your consumption? Is there savings you could make there to take some of the pressure of your batteries and solar... Also, Tesla Powerwall's are perhaps one of the most expensive methods of adding home energy storage.

[@video99couk]

By far my biggest consumption is the business, and I really can't do anything to reduce that load and do the work. It consists of computers, monitors, video equipment and air conditioning.

[@TTVEaGMXde]

The fact that the weather forecast is important when battery capacity is limited is also true in other countries, but I have not heard of it here. Flexible electricity prices are still very new in Germany because the electricity meters from the 1950s 🤣have to be removed first. The fact that electricity feed-in is poorly paid is nothing new to me.

[@TheRealHarrypm]

It's getting common to see 300-550w pannels edge to edge with rooftops in Oxfordshire after the last rates change 500-700GBP/m with a standard family home is just untennable, when for about 11k you can just get solar at cost and go grid free if you really start cutting everything to DC that does not need AC power, almost everything is 12~5v these days, mini-split AC can all run DC. It's very worring having a battery system tired down by anything past a BMS for each cell pack ideally such a battery system should never really be dependent on the outside world, its also worth noting most industral setups will trigger secondary lights to indicate switchover for generators. It's always been rule of thumb to have 2-3 days energy backup with a solar system, though instantly the installer fees with stuff like Teslas power walls make it seem just impractical compared to out of pocket setup for most people with the right land.

[@richiereyn]

I had solar panels fitted a couple of years ago, at peak we get nearly 7Kw. We are also on Economy 10 which gives us 10 hours of economy rate [midnight - 5am, 1pm - 4pm and 8pm - 10pm]. We also have an EV which can use the solar to charge during the day, so the power generated goes towards the EV and running household appliances, and any surplus goes back to the grid. Last year we had around £700 back from E-on which was a nice surprise. I have thought about battery storage as well, but I am not yet convinced of their safety as they have the potential to fail and go into thermal runaway. I am extremely pedantic about parking the EV at the top of the drive, so should it ever catch fire it is well away from the house. If a lithium fire were to break out, it could be very difficult to extinguish. So I am taking a wait-and-see approach to see how things progress over time.

[@video99couk]

As far as I'm aware, there are zero cases of Tesla Powerwall fires in the UK, but one possible case in USA. But if mounted outside, there's pretty much no chance of serious damage anyway. I do agree, if you have an EV that can take surplus charge, that alters the maths for having a Powerwall. I don't think we would have had a second Powerwall if we had an EV.

[@markedwards4879]

18:14 The Firmware in the UK models must be different to what we have here in Australia. When our grid fails the power wall switchover is instant. I do have UPS'es connected to most computer equipment anyway but the most that we get is a single beep from them as they report the the grid did something. No lights flicker and machines not on the UPS don't even notice the switch. Ironically I'm sitting here typing this while the house is off grid since there is scheduled work out on the street. It's winter here and the sun is very low so shading on my solar array from surrounding trees is terrible, but the house is running as normal with the heat pump (reverse cycle air conditioning) is keeping the house a 21º with free solar energy. If the battery gets full it regulates the solar automatically by slightly raising its output frequency. All very seamless.

[@video99couk]

It's certainly not seamless here, the power goes off for about a second before the Powerwall kicks in. Maybe you have a newer Tesla Gateway which can switch over quicker. It would certainly be better if it were almost instant.

[@markedwards4879]

@@video99couk I have a gen 2 gateway, which version do you have?

[@outsdr]

I find it very interesting that you have the Powerwall batteries AND you sell excess energy back into the grid. Here in New Mexico, USA, when I looked into solar for my house, the companies told us it is either Powerwall or feeding back into the grid, the electric company does not allow both, supposedly because if there is a power outage, they don't want power being fed into the grid. They don't explain how this is any different without the Powerwall, since if the power goes out during the day, solar panels will still be feeding back into the grid. 🙄

[@video99couk]

Yes that is allowed here. There's even a tariff which permits powering the grid from the Powerwall.

[@FireballXL55]

The inverters should not feed into the grid when the grid power is off that is a requirement in the UK. We can feed into the grid while it is up and running though.

[@barrieshepherd7694]

Given the variability of UK weather and the ability of the forecasters I would think anything planning future activity on the local weather forecast to be fundamentally flawed!

[@video99couk]

It gets it roughly right about 90% of the time. Like today, rain predicted all day. Charged to 100% overnight. Rained all day just like it was supposed to.

[@commuterbranchline8132]

U.K. Powerwalls 3 released today, 18th June 2024. Could I buy 3 Powerwall 3’s and have a total of 36 440w Bifacial solar panels feeding DC into the batteries. We use an average of 60kw per day at home with 3 EV’s, heat pump and electric cooking in our house.

[@video99couk]

Yes that sounds perfectly possible. I don't know how it works in terms of some batteries getting more charge than others, which is inevitable if different panels are connected to each.

[@MVVblog]

Solar power systems aren't viable from a return on investment perspective, even here in Tuscany. Maybe they are in Sardinia or southern Italy.

[@video99couk]

Everyone is different, it depends on your use case. In our case, we're over half way through the investment in the original system which was installed less than 3 years ago.

[@tonep3168]

@@video99couk That’s fantastic! Our power bills are substantially lower than in the UK, which is why you benefit so nicely!

[@apiscator444]

Standing charges need reducing for solar users

[@apiscator444]

Roumer is gateway wont be needed in future

[@tonep3168]

Looking it your consumption, I’d say your powerwall is 3 or 4 times too small. Adding an additional Powerwall 3 would maybe do the job. But to be honest, I can’t see how a solar power system can be viable in the UK, from a return on investment perspective, It is not viable here in Denmark, which is roughly the same, just with colder winters. Also, you say your solar is 6kW, yet only gives you 5kW. That’s why Powerwall 3 makes more sense. But I guess you also needed a separate Solar Charge Converter, which is not built in to PW2. Another thing to note is that the inverter output of PW3 is 11.5kW, however the battery charger can still only charge the battery pack a 5kW. Also PW3 has 6 MPPT solar inputs, and can take up to 20kW, not 5kW. My personal opinion of Powerwall 3 is that is is far from perfect, and really should be sold in 2 versions, one with the gateway, MPPT charger, and inverter, and then a basic model which is just a battery pack and its charging hardware for existing PW3 installations. I also think the cell charger is underrated, and should be beefed up, and some more capacity would be good. I guess that might be in the next model.

[@video99couk]

The Powerwall 3 has the same capacity as the Powerwall 2. With two Powerwall 2's, the capacity is ample for most of the year. In the worst case of rainy days in winter, it won't suffice, but for much of the year there is more than enough capacity. If we added a third Powerwall, it would not be financially worth it because for most of the year the capacity would be surplus. We could upgrade our 5kW inverter to 6kW, and indeed when we do have to replace it one day, we will do so.

[@tonep3168]

@@video99couk Very true. It’s a nice little system you have. I keep checking up on the market every few years, as I would love to have a system like yours, but the government here took away the incentives a few years ago, and now it’s just not worth it, by any stretch of the imagination. All the time my wife is the minister of finance, I’m not going to be allowed, unless prices drop substantially in the next few years.

[@edc1569]

Solar is pretty cheap to install, most systems pay themselves off in less 10 years.