Considering getting a Powerwall

[kuruma]

we love ours and with only two of us in the house find that we can charge the Powerwall and car before 4am and then run the entire house (with us home all day) on the Powerwall before it starts charging again at midnight. And that's in the depths of winter. We're in the middle of a switch to Octopus Go once we get smart meter installed and then we'll halve our energy costs.

With solar now becoming more of a contributor as we move into Feb, we're finding that by bedtime, more and more of our PW charge is left because of the solar boost (6.4kW panels installed) and that we've actually fed back into the grid at some point each day.

Storm Watch mode was a surprise last night. Received a notification last night from the PW that as there was a storm on the way, the PW was being charged to 100% in readiness for potential power cuts. Didn't even know that mode existed. Seems to have been an update since our install in Dec.

It makes as much financial sense to get a PW as it does to buy a c. £40k car. But it makes as much sense as the car from an energy resource management POV.

 

[jimbo_hippo]

Didn't even know that mode existed. Seems to have been an update since our install in Dec.

Kurama, if you scroll to the bottom of the PowerWall page in your app and press on the version number it’ll give you a version history.

 

[im85288]

we love ours and with only two of us in the house find that we can charge the Powerwall and car before 4am and then run the entire house (with us home all day) on the Powerwall before it starts charging again at midnight. And that's in the depths of winter. We're in the middle of a switch to Octopus Go once we get smart meter installed and then we'll halve our energy costs.

With solar now becoming more of a contributor as we move into Feb, we're finding that by bedtime, more and more of our PW charge is left because of the solar boost (6.4kW panels installed) and that we've actually fed back into the grid at some point each day.

Storm Watch mode was a surprise last night. Received a notification last night from the PW that as there was a storm on the way, the PW was being charged to 100% in readiness for potential power cuts. Didn't even know that mode existed. Seems to have been an update since our install in Dec.

It makes as much financial sense to get a PW as it does to buy a c. £40k car. But it makes as much sense as the car from an energy resource management POV.

You pretty much have the same setup as I do and we are both in the north east where solar generation is beginning to kick in. I have just moved from the Octopus Go tariff to their Agile one as I think it’s going to be cheaper especially given that the powerwall will cover the most expensive time slot (between 4pm and 7pm roughly) and be able to benefit from some time slots for charging the powerwall/car where it’s less than 1p per kWh.

Also got the storm watch notification but luckily turned it off as I didn’t want it charging at peak tariff!

 

[Kenners]

Can you use a power wall to just charge during an off peak electricity period, which is quite a bit cheaper, and use during peak periods? Or do you have to have a solar set up? If you are on a renewable tariff already, installing panels seems a bit pointless.

 

[im85288]

Yes you can use the powerwall without having solar panels and do exactly as you described but it’s main benefit really is consuming excess solar that would otherwise go to the grid so that it can be used later.

I had my powerwall and solar installed last November and to be honest there was hardly any solar generation at that time so for most of November, December and large parts of January I was filling it up at 5p off peak (octopus go) then using it the rest of the day.

 

[KennethS]

I am very tempted to get the Powerwall at my home. We have solar but only a 3.5kW system installed some years ago. I know the PW is not necessarily an economically justifiable expense, but I do think it is the environmentally friendly thing to do and I like technology. Despite my best efforts to improve our home efficiency we consume a lot of electric in our home so I am keen to try and do our part. Does anyone have a recent install that can give me an idea of how long it takes from order to install?

 

[MrBadger]

but I do think it is the environmentally friendly thing to do

But its not. It has 20% round trip losses so except on very rare occasions when marginal generation (what adjusts to cater for someone flicking a switch) is not gas, its actually consuming 20% more gas than using electricity direct from grid.

 

[kuruma]

but if it's from the sun, which it will be most of the year where we are, then...

 

[MrBadger]

but if it's from the sun, which it will be most of the year where we are, then...

It still causes more gas to be burned. Your solar is better being exported and being used by someone else instead of them causing more gas to be burned. There are rare exceptions, but in general, the grid normally does a pretty good job at managing supply and demand. However, there are other benefits to batteries, but time shifting isn't one of them.

Don't get me wrong, I'm not anti battery (I've almost bought Powerwall on several occasions), but you cannot justify them on cost or environmental grounds. But each year, the balance point changes, but where we are at present, its some way away and its better playing the waiting game.

 

[gangzoom]

It makes as much financial sense to get a PW as it does to buy a c. £40k car. But it makes as much sense as the car from an energy resource management POV.

I would agree, our PW is constantly working, either charging or discharging, whilst our car sits there doing nothing 99% of the day.

For the same size battery in our X you can make 5 PWs.

I've also just got an electric pedal bike which am going to start using for my 4 mile commute instead of the car. Been electric I can get to work not sweaty, and turn off the assistance for the trip home to get me fit.

The bike with its tiny 0.25kWh battery will do the commute for a week without charging, where as our Tesla also require charging after vampire drain given and consume some 80kWh after charging losses.

The fact from the same battery size as one Tesla you can make 300 eBikes shows what a waste of batteries even EVs are for personal transportation.

 

[nightowl]

Out of curiosity, what's the main thing that would affect the battery lifespan? I'm guessing it's charge/discharge frequency?

Bearing in mind the 20% loss if charging up overnight and then using the power during the day, combined with it being less likely to be using renewables during the off-peak/night rate, would it be likely to keep the battery in a better condition for longer by just charging it from solar?

Or, if the battery being left discharged for a long time is bad for it as well, only using off-peak to charge it a small amount in winter?

Obviously it would take longer to pay for itself but as it probably won't ever pay for itself entirely anyway I'm wondering whether there's some balance between being green / keeping the battery healthy.

 

[SirRob]

I'm very interested in getting solar and a powerwall in the future, but it doesn't seem to be 'time' yet. I'm expecting some kind of price crash in the next few years.

 

[MrBadger]

Out of curiosity, what's the main thing that would affect the battery lifespan? I'm guessing it's charge/discharge frequency?

Yes, but a partial charge or discharge does not count as a full charge/discharge cycle. So lots of little charges does not really affect things much in the same way as regen in the car does not really impact things. Simplistically, say you discharged to 50%, then topped right up, thats really half a charge not a full charge. Also, I believe that 0 and 100% is not so much of an impact as on car. iirc there is more battery than 'usable' and its a different chemistry to what is in the car. Also worth bearing in mind, that even an aged 70% capacity battery has quite a lot of useful life - many on grid battery owners have much smaller battery capacities than offered by powerwall - 4kWh are quite common so 70% is still a decent size.

 

[kuruma]

woke up this morning to find that the PW had kept us running while there was a power cut for an hour. First time it's actually had to do that since the December install. Glad it's there to keep the breadmaker going!

 

[Martinb999]

Seriously thinking of installing a powerwall. We have a 3.5kwh solar array and wonder what it would cost to install? Anyone give me a ball park figure in the SE?

 

[opals]

Ours cost ~£9k a couple of weeks ago, with very little additional wiring required.

 

[Martinb999]

Thanks OPALS

 

[WannabeOwner]

If you have one, what were your reasons for choosing it and how useful have you found it?

I have a number of servers running here, so my power consumption is higher than normal-domestic, and as such I do have a pay back from either buying power cheap rate overnight, or from self-generated solar. I figure that payback is only achieved with higher consumption, and with advent of LCD etc. that is probably not "most people". I've been frugal for years to be Eco, and it is nice, now I have battery and eco-power, to have the garden lights on each evening in winter, and not just "when we have company"

They say the switchover is seamless an not noticeable...

There is definitely a break here (I'm on single phase). Dunno what the difference is ... I have Gateway and Solar, but I assume that is the same as everyone else.

Previous storm the power was off for several hours, I was working and had deadlines, and would have been properly annoyed if I couldn't have got on. I'm not on minimum wage so a few one-off events like that and Payback will be solved ...

 

[WannabeOwner]

It has 20% round trip losses so except on very rare occasions when marginal generation (what adjusts to cater for someone flicking a switch) is not gas, its actually consuming 20% more gas than using electricity direct from grid

Is this typically the case? What if charge battery overnight such that it uses North Sea Wind that would otherwise be curtailed. i.e. not displacing someone else to Gas (I presume?)

 

[markharro]

we love ours and with only two of us in the house find that we can charge the Powerwall and car before 4am and then run the entire house (with us home all day) on the Powerwall before it starts charging again at midnight. And that's in the depths of winter. We're in the middle of a switch to Octopus Go once we get smart meter installed and then we'll halve our energy costs.

With solar now becoming more of a contributor as we move into Feb, we're finding that by bedtime, more and more of our PW charge is left because of the solar boost (6.4kW panels installed) and that we've actually fed back into the grid at some point each day.

Storm Watch mode was a surprise last night. Received a notification last night from the PW that as there was a storm on the way, the PW was being charged to 100% in readiness for potential power cuts. Didn't even know that mode existed. Seems to have been an update since our install in Dec.

It makes as much financial sense to get a PW as it does to buy a c. £40k car. But it makes as much sense as the car from an energy resource management POV.

Hi @kuruma is it possible to charge a completely empty PW to 100% on the cheap night time Octopus tariff and then basically run your house during the day from the battery. We have a long term plan to fit solar PV but I am wondering if a PW atm would be worthwhile to reduce our ridiculously high electricity spend? Thanks