phil4
Member
For the next 12 months, losses don't matter. I don't charge the PWs from solar, that goes out to the grid.
As such I believe the efficiency is the same as a hybrid setup.
Last edited:
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Solar Panels UK - is it worth it?
- Thread starter jdwuk
- Start date
As such I believe the efficiency is the same as a hybrid setup.
Pink Duck
Active Member
I briefly caught PW2.1 charging a little from excess solar this morning, despite being on Octopus IO+Outgoing Fixed tariff too.
Was only 600 W, probably low enough to warrant avoiding transformer loss for its own benefit.
Also noticed it halting discharge overnight at the same time that IO was between its scheduled charge sessions, which seems to be a pattern lately.
Was only 600 W, probably low enough to warrant avoiding transformer loss for its own benefit.
Also noticed it halting discharge overnight at the same time that IO was between its scheduled charge sessions, which seems to be a pattern lately.
Last edited:
Looks like the 5kW inverter it is.
I did consider waiting for the PW3 but it’s potentially £thousands more (the PW2 price has reduced since PW3 announced). I’ll also be waiting longer for installation so will miss out on some solar generation in the meantime and I’d miss out on the £350 rebate from Tesla. Also the PW3 is deeper than the PW2, not by much but enough that it could cause issues in the narrow passageway it will be installed in.
Thanks all, it’s been really useful.
I did consider waiting for the PW3 but it’s potentially £thousands more (the PW2 price has reduced since PW3 announced). I’ll also be waiting longer for installation so will miss out on some solar generation in the meantime and I’d miss out on the £350 rebate from Tesla. Also the PW3 is deeper than the PW2, not by much but enough that it could cause issues in the narrow passageway it will be installed in.
Thanks all, it’s been really useful.
Pete UK
Member
Decision made then 
My DNO application came back in 45 calendar days by the way. At 23:59
this was about 3 months ago now. Mine was for 10kW export - not sure if that makes any difference. I’m sure you’ll get a 5kW one through no problem.
You could pay your installer to put an application in straight away. Before you’ve even paid a deposit to get the ball rolling. That way you’ll know if it would be approved earlier. But sounds like you’re about to push the button soon anyway.
Good luck.
My DNO application came back in 45 calendar days by the way. At 23:59
this was about 3 months ago now. Mine was for 10kW export - not sure if that makes any difference. I’m sure you’ll get a 5kW one through no problem.You could pay your installer to put an application in straight away. Before you’ve even paid a deposit to get the ball rolling. That way you’ll know if it would be approved earlier. But sounds like you’re about to push the button soon anyway.
Good luck.
Have just been discussing it with installer and they are going to put the application in straight awayDecision made then
My DNO application came back in 45 calendar days by the way. At 23:59
You could pay your installer to put an application in straight away. Before you’ve even paid a deposit to get the ball rolling. That way you’ll know if it would be approved earlier. But sounds like you’re about to push the button soon anyway.
Good luck.
Plenty of other vendors of hybrid inverters exist if you are happy to have another app, Giv Energy, Sunsynk, SolarEdge, etc. I bet whatever solar inverter you are looking at will be able to connect batteries that will be cheaper than PW2.
Also remember that PW2 is not a LiFE battery, and generally that seems like a poor idea for this type of use. Other inverters already use LiFE, Tesla are only getting there with PW3.
It is a Solaredge inverter I’m going for. I have already looked at Givenergy and Solaredge batteries. Costs are not that much different to the price I’m paying for the PW2. But biggest negative is they’re about twice the depth of the PW2 which won’t work in the narrow passage way we’re putting the PW2 in.
WannabeOwner
Well-Known Member
Startup would be the only thing I'm aware of, but I'm not technical ...
... sounds like you don't have to worry about that then! Maybe just check with installer that the bigger one [the brand of their choice] doesn't need a big start-up voltage?
Solar order has been placed, now waiting for G99 application to go through.
I had already arranged with a different electrician to fit a Zappi which he's now ready to do. So he is fitting the charger long before the solar and Powerwall will be installed.
He's asked if I'm looking to keep the battery separate from the Zappi. I've asked for clarification but what does that mean? I know I need to have the option to charge the car from the solar output if required. I'm guessing I also want the option to charge the car from the Powerwall too?
How have others with an AC battery and Zappi got it all set up? Do I need an Eddi or is all down to where the CT clamps are connected?
I had already arranged with a different electrician to fit a Zappi which he's now ready to do. So he is fitting the charger long before the solar and Powerwall will be installed.
He's asked if I'm looking to keep the battery separate from the Zappi. I've asked for clarification but what does that mean? I know I need to have the option to charge the car from the solar output if required. I'm guessing I also want the option to charge the car from the Powerwall too?
How have others with an AC battery and Zappi got it all set up? Do I need an Eddi or is all down to where the CT clamps are connected?
My Zappi’s can charge from The Powerwalls or the grid.
some people have their Zappi’s connected out the sight of Powerwalls.
the reason for this is that the Zappi’s won’t drain the Powerwall by mistake.
the only way to charge from the grid when Powerwalls can see the Zappi, is to increase the reserve. e.g anticipated PW level at 00:30 55%. Set reserve to 60%. Car will charge from grid
Powerewall will charge to some degree depending on AI
some people have their Zappi’s connected out the sight of Powerwalls.
the reason for this is that the Zappi’s won’t drain the Powerwall by mistake.
the only way to charge from the grid when Powerwalls can see the Zappi, is to increase the reserve. e.g anticipated PW level at 00:30 55%. Set reserve to 60%. Car will charge from grid
Powerewall will charge to some degree depending on AI
Thanks. With hindsight would you have it set up the other way?
With Intelligent Octopus, I envisage charging both the PW2 and the car in the off peak window so at least while IO exists I can't see the need to charge the car from the PW2. With low daily usage of the car and topping it up each night, it would rarely need much of a charge.
It sounds less troublesome to keep the Zappi and PW2 separate?
WannabeOwner
Well-Known Member
I have Zappi (as my second charger, the other is Tesla (dumb).
I assumed I would use Zappi for overspill to car (when it detected PV excess was exporting to grid)
I don't use it like that, I just have it in "dumb" mode, and control everything from the car
If I come home and want to charge (immediately) I don't want to have to tell car to charge and also override Zappi (and remember to un-override it later)
If a mate comes and plugs in I want his car to start charging without me having to override / disable Charger schedules etc.
If I plug Car-A into Charger-B, instead of its normal Charger-A, then schedules / preferences defined at the Charger would be wrong for the car. I think this will become a snag as people acquire 2x EVs and chargers
When my Home Help has an EV I'll be very happy they plug in and use up my excess PV once my car is full (and assuming Octopus is not paying me handsomely to export
)If car is charging from PV and PV stops generating I want something to decide what to do. Stop/Starting is not good for the contacts. Zappi has a "tolerance" to carry on for a bit before giving up, but I think its a bit of a blunt instrument approach. My API homebrew stuff will reduce AMPs if the PV power falls, and will allow the Battery to drop a couple of percent before actually stopping charging. When PV resumes it will stay on low AMPs (if it hasn't stopped) until the battery has regained that 2% and then ramp up
Also, my case is a bit non-standard, my PV generates 14-15kW at peak. Charging battery first, and then car, means that car will take max 7kW so I'll be exporting. And I think Powerwalls charging at the max 10kW is not ideal for longevity, so if my API-thingie reckons its going to be a bumper PV day it charges car concurrently whilst the battery charges, to reduce kW to the battery, make the battery keep charging to, say, 3PM before reaching 100% and then the PV output has fallen such that car taking 7kW is more than the excess coming off the PV
phil4
Member
When I only had solar and zappi, it was quite easy to set the zappi to run of solar.
Now with powerwalls I can do that, but tell the zappi to allow 50/100W export before it starts charging... so it won't drain the powerwall. But it also won't charge unless the powerwall is not charging. So with PV it has to be car charging last, after house and battery. I could remove that export restriction but then it may charge from battery/solar depending on clouds etc.
Octopus Intelligent is easy, just tell the PW it's a super off peak period, and the car and battery will charge from the mains. I don't often get outside the normal slots, so if I do I just enter them manually.
Now with powerwalls I can do that, but tell the zappi to allow 50/100W export before it starts charging... so it won't drain the powerwall. But it also won't charge unless the powerwall is not charging. So with PV it has to be car charging last, after house and battery. I could remove that export restriction but then it may charge from battery/solar depending on clouds etc.
Octopus Intelligent is easy, just tell the PW it's a super off peak period, and the car and battery will charge from the mains. I don't often get outside the normal slots, so if I do I just enter them manually.
Thanks. Are you currently exporting PV to take advantage of the 15p/unit Octopus are paying?
If that is still available when everything is fitted I'm hoping the following is possible...
- Export everything produced by PV at 15p/unit
- Charge the PW2, top up car and maybe run the washing machine/dishwasher in the IO off-peak window
- Use the PW2 to power the house during the peak hours
Is that relatively easily achievable if I have it set up so the Zappi can see the PW2?
I appreciate the 15p export and IO might not exist in the future so plans will likely need to change at some point.
phil4
Member
Yep, doing the 15p export.
Yes, everything you've described is what I do, and yes my Zappi and PW2 are aware of each other (the PW2 sees it as house load).
As you can see above, I've also used that setup when export wasn't warranted, and indeed when I had no battery... so I've almost tried it every way possible.
One thing I would say is when I wasn't exporting, and so wanted to use solar to power the house/battery, it was useful to have the zappi seen by the PW. Imagine you've had a really sunny day, your house has been powered by solar, and your battery is as 90% as a result. Tomorrow is set to be really sunny, and so you could really do with the PW down at 30%. If like me you can't export, you can at least charge the car, which then drops the PW down to where it needs to be.
That's great, exactly what I needed, I'll let the sparky know. Many thanks.
Pete UK
Member
Just a thought (I know you’ve made you’re decision already though
)You could always mount the PW3 higher up the wall above head hight, to allow more space in the side passage, unless perhaps you live in a bungalow?
Not sure the installers would be very pleased lifting it up - but it should be possible.
Not a bungalow but the passageway runs the full length of a single storey extension. I wouldn't want it above the extension on the side of the main house as it would be really exposed (to weather and people). It will be nicely hidden away and well sheltered on the side of the extension.Just a thought (I know you’ve made you’re decision already though
You could always mount the PW3 higher up the wall above head hight, to allow more space in the side passage, unless perhaps you live in a bungalow?
Not sure the installers would be very pleased lifting it up - but it should be possible.
I'm not sure what price the PW3 will be but I've seen estimates of between £11k and £15k. I'm paying a lot less than that for the PW2. Over a 10 year period I'm not sure I'll lose enough round trip energy to warrant the extra cost of a PW3. And I'm too impatient to wait even longer
