New Installation … Probably basic questions

Hi All,

Brand new to the solar community, literally had my new system commissioned yesterday, so very much familiarising myself with the system and am hoping my ‘basic’ questions don’t come across as silly. I have searched the forums on here and read a fair bit, but don’t think I’ve found the answers (or at least ones that I understand).

So I have the following:

• 15x JA Solar Panels (on two strings)
• GIV-HY5.0 Inverter
• 9.5kw Battery
• Zappi Charger (for the Tesla M3)

I am on the Octopus Intelligent Go tariff and just signed up for the export (went for the fixed 15p export, just while I learn how this all works).

My intention on the outset is to:

• Use solar to power the house
• Use the battery to top up what the house needs
  - Last resort, draw down from the grid
• Excess to the grid (if there is any) or many charge the EV if that is even possible?

Am I looking at this the right way …. Obviously in winter it will be more down to the battery power the house (might need to invest in a second battery) (work from home, both wife and I and have a hot-tub [that’s on all year round]

My questions:

The Zappi is connected to Octopus who define the charge schedule based on the best rates, I presume there is no actual need to change this?

Is there a way to get the Zappi into the GivEnergy portal/app … I can’t seem to find any reference of being able to do that. From some reading, it appears that if I have a Harvi, that can do that (something about getting the GivEnergy kit into the MyEnergi App.

I’ve read about the Smart Plugs (although read the post about it nearly burning someone’s house down), but is there any way to measure how much energy the hot tub is using, like with a separate CT clamp or something or does that need some other solution … more curiosity on my part.

Would there any benefit to considering a move to the GivEnergy EV charger (doesn’t appear it’s ’certified’ with Octopus) … again just curiosity.

Thanks in advance

FunkMaster hello, welcome!

15p export is the right place to be, Agile isn't worth it at the moment and you could only get higher if you went with Flux, but the cheap rate isn't as cheap as IOG.

You might need to do some setting changes to how the system sees the usage when the car charges, depending on where your CT clamp is, as if it's detected as load the battery could discharge into the car.

Otherwise set the inverter to Eco mode, this will do most of what you want. You'd need to set the Zappi up so it sees the export and diverts it to the car if you want (not sure on the settings and I think it only does this at 1.4kW+ of export), but at 15p export vs a cheaper import it's probably not worth doing that unless you want to be super eco friendly!

To answer your questions:
No need to change your charge schedule with Octopus/Zappi, it should keep working as normal. Might want to set a charge on the battery as mentioned above to prevent it from discharging into the car.

There isn't a way to get your Zappi in the GE portal unfortunately, some people use home assistant to have one view, but this involves some more outlay and dedicated hardware.

The smart plugs can be included in the app to do this, but 3rd parties or things like a Shelly which can monitor energy are available, but won't go in the portal so home assistant is best for this.

Only benefit to the GE charger would be to integrate it into the portal to have everything in one view, but as you say it's not certified so you might lose out on IOG in that case unless the car is (I don't have an EV so not sure).

FunkMaster Hi All,

Welcome...

15x JA Solar Panels (on two strings)
GIV-HY5.0 Inverter
9.5kw Battery
Zappi Charger (for the Tesla M3)

I am on the Octopus Intelligent Go tariff and just signed up for the export (went for the fixed 15p export, just while I learn how this all works).

Very similar to my setup

My intention on the outset is to:

Use solar to power the house
Use the battery to top up what the house needs
- Last resort, draw down from the grid
Excess to the grid (if there is any) or many charge the EV if that is even possible?

You can configure Zappi to do solar charging. In fact, without making any changes, the Zappi will grab the exported solar and charge the car, since IOG requires that the charger is in Eco+ mode. But charging from grid is 7.5, whereas export is 15p, so better to export the solar. I used the Zappi's export margin parameter to effectively disable solar charging.

Except... if it's a brand new install, you won't have got your export MPAN yet, and until you get that set up, you won't get paid for solar. So in the short term, may as well charge car from solar.

You also need to configure things carefully to avoid the GE battery draining into the car. Ideally, you want the CT clamps arranged so that the GE system doesn't see the Zappi at all, and therefore doesn't feel the need the need to supply power when Octopus are charging the car.

Do you plan to charge the GE battery overnight on cheap rate ? What I currently do is charge battery to around 40% overnight, then export as much solar directly as I can, and then dump excess battery back to the grid in the evening. But obviously, you won't want to do anything like this this until you get paid for export.

My questions:

The Zappi is connected to Octopus who define the charge schedule based on the best rates, I presume there is no actual need to change this?

You have to leave it this way, to satisfy requirements for the tariff.

Would there any benefit to considering a move to the GivEnergy EV charger (doesn’t appear it’s ’certified’ with Octopus) … again just curiosity.

You probably qualify for IOT via the Tesla anyway. It's hard to know how many people are happy with the GE charger - we see quite a few complaints on here, but people typically only post when they have trouble...

Hey,

Thanks for your responses, much appreciated.

I applied for the export MPAN, so indeed I intend to dump to the grid or have excess dumped there, when it gets sorted. Till then, will try maximise my usage into the home. Didn’t have the EV plugged in (have a skip in the way for some other building work) but will take a look to see.

This is what my Zappi isn’t configured with for IOG:

I was looking at this flow chart this morning and trying to understand why at one moment the battery is discharging to the grid and then a few moments later the grid is pushing to my house.

I thought the house would draw from solar / battery and only if there wasn’t enough it would ask the grid for some.

The battery is in Eco from what I can see and the only thing I set was to charge on the cheap rate.

FunkMaster there is always a bit of give and take to the grid, it’s normal. Say you put the kettle on, 3kW load. Inverter needs time to detect this load and ramp up battery discharge to match.

So energy in those few seconds (typically) is supplied from the grid. When the kettle finishes, the extra discharge is then for a few seconds exported back to the grid as the ramp down isn’t instant either. Plus the inverters use the tiny bit of back/forth to keep themselves in sync with the grid power frequency etc. it amounts to pennies overall, so nothing to worry about

FunkMaster you can't expect grid usage to be exactly 0 - the inverter has to react to changes in usage, which introduces a delay. When you put the kettle on, that will cause an instant draw of, say, 2kW. Only after has happened will the inverter see the spike via the CT clamp, and then has to decide to increase battery discharge (or reduce battery charge rate, if it's sunny), and that too will take a short time. Same in reverse when the kettle turns off.

It's actually quite impressive that it is able to keep it so close to balance.

The other thing is that the portal records snapshots, rather than averages, every 5 mins (or faster if you are running the app). So that is subject to sampling errors

FunkMaster on the zappi, I had got the impression from somewhere that if you tried to change mode, octopus would always set it back to eco+. However, that's not true of 'stop' mode, so you can use that to inhibit accidental solar charging. I run a script which uses the API to turn it to stop mode every morning (around 10am iirc), and then turn it to eco+ in the evening only if I want to charge.

DD Thanks, makes a lot of sense now ... I was worried I did something wrong.

DD I've been dabbling in homeassistant, but never really took it seriously, so will revisit this as I become familiar with this all.

DD You also need to configure things carefully to avoid the GE battery draining into the car. Ideally, you want the CT clamps arranged so that the GE system doesn't see the Zappi at all, and therefore doesn't feel the need the need to supply power when Octopus are charging the car.

I noticed today that the battery was discharging to the car … you mention something about charging from solar as an option, do I have to move a CT clamp somewhere.

I’ll have to take some pics of what is wired where

FunkMaster I noticed today that the battery was discharging to the car … you mention something about charging from solar as an option, do I have to move a CT clamp somewhere.

The problem is that the zappi can be consuming the solar export. The sun goes behind a cloud, but the zappi doesn't immediately respond. The GE sees that there's some grid import, so starts discharging the battery to cover it. Zappi is unaware this has happened, and continues to draw the same power. It's now in a stable, but undesirable, state - GE sees that grid import is close to 0, and is happy; zappi sees that it is consuming all export, and is happy.

There is a parameter on the zappi that can help - the export margin. That tells the Zappi to always leave some export power going to the grid. Could use 100W but I found that quite slow to react, so used 300W IIRC. Now, Zappi tries to leave 300W exporting. If the sun goes behind a cloud as before, GE steps in as before to supply shortfall from battery, but now Zappi responds by reducing charging power in order to leave 300W exporting. And so they march down until the GE battery is not discharing and it's only solar export being consumed by zappi.

But yes, better still is to wire things so that GE doesn't see the Zappi. Now, GE believes the power is being exported, and doesn't care what it's being used for. And in particular, has no reason to make up any shortfall when solar drops.

Thanks mate … think I came across a vid this morning (https://youtu.be/EmxN-gJaGUw?si=2mGHon1rfouxzl6d) of a guy who seems to have explained the same thing …

I’ll take a look where it’s all wired and see if there is an obvious place to put the Zappi clamp, which if I understand this all, basically needs to be as close to the main meter (smart meter) as possible …

Is moving the CT clamp a job for an electrician or can this be done DIY?

For reference this is what the config looks like.

From what I can see, the Zappi CT is on the same live tail as the PV.

DD I have found that the Zappi works well and is more responsive if there is an extra CT on the AC Inverter output going into the Consumer unit. Since fitting one the Zappi responds better to changes in production.

You can get one from Givenergy or Myenergi but I was fortunate that I had one I was not using from our Eddi as the Eddi and Zappi are connected via wifi and share the CT clamp connected to the grid supply. So, I could use the clamp supplied with the Eddi elsewhere.

I not changed any of the CT Clamp configuration, as am not really sure if I am supposed to or not, so I’ve just set the export Margin on the Zappi to 100W and see what that does.

Will leave it and see what happens … but so far I can see the car charging from Solar (has have excess and waiting for my MPAN export).

Will see what happens tonight I suppose or when the house suddenly needs more power (maybe I should go cook something, put the dishwasher, tumble dryer and washing machine on).

Plugged the car in and octopus set their IOG schedule on it

Made sure Zappi is in ECO+

killythebid I have found that the Zappi works well and is more responsive if there is an extra CT on the AC Inverter output going into the Consumer unit. Since fitting one the Zappi responds better to changes in production.

I do also have a CT clamp for the Zappi on the AC inverter output, but because it's a hybrid inverter, there's no way for it to distinguish solar from battery discharge. Zappi does have a "do not drain battery" mode, but I'm not sure it's that useful in this configuration ? (The extra CT clamp was installed from the outset, but wasn't correctly configured initially, when I was doing my experiments. It's quite possible that it does improve responses.)

DD
Wouldn't it make more sense to fully charge the battery at night, dump almost everything from it in the morning so that if it's a sunny day you can capture up to 7500w of power from the array?

DD I have a Hybrid setup too and I think you are correct the "do not drain" mode on the Zappi has no effect unless the battery is AC coupled, it talks about that in some of the Myenergi installation literature I have seen. But as I said the Zappi does react better to carrying generation with the extra CT clamp on the inverter AC output.

It is a case if it plays well with the Givenergy system but it is not perfect by any means. It's good enough for how I use it though. I do not see any reason to change a Givenergy charger, given the expense of doing so for what seems little benefit.

dragos.balaban Wouldn't it make more sense to fully charge the battery at night, dump almost everything from it in the morning so that if it's a sunny day you can capture up to 7500w of power from the array?

Yes, I could churn the battery more by filling it up then discharging down to 40%, rather than only filling up to 40%. That might give me an extra 5kW for around 7p/kWh profit per kWh, so 35p a day.

FunkMaster For some reason, it won't let me upload a photo of my CT configuration, but basically I got my installer to add a second brown block. The zappi comes off the first one, and then the second one is fed from the first one and in turn feeds the GE and the house. The Zappi clamp is on the meter tails, and the GE one is on the loop between the two brown blocks, so that it sees only the current going into the house and GE.

DD think the brown box would be called a Henley Block?

Might help ask for the right thing when speaking to an electrician. 😀

TX200 yes, though the installers always referred to them as just "block" - didn't once called them Henley block.