Which EV charger for Giv energy bay/solar setup?

Hi folks,

Had my giv energy solar/battery 9.5kw, system for two years, just acquired a PHEV (Too good a price) so other than granny charging need a EV charger that can use solar (if required) that can also ‘see’ home battery and not pull from this (appreciate ideally set both to charge if on low tariff rate at night as a quick fix anyone do this???).
I’m sceptical with giv energy EV charger despite this being the most obvious integration to the system with so much mentioned nowadays regarding poor communication/support wondering if I’ll get!!!
Or look at hypervolt for example, that have solar support but no integration and potential risk of the installer(sorry) having poor knowledge issues with my setup. Any advice or experiences/recommendations welcomed.

Plenty of comments on here from other EV charger owners.

I would suggest you get an EV charger that is compatible with Octopus Intelligent Go to give you best future flexibility (the GivEV charger unfortunately still isn’t).

Charging your EV from solar isn’t that (financially) important, with export rates of 15p and overnight EV charge rates half that, it makes sense to charge overnight and export all your solar.

If you have a hybrid inverter then an EV charger can’t really “see” the battery and prioritise charging off solar and not the battery. Far simpler is to get the electrician to wire the EV charger as the first device after your meter and the inverter CT clamps are after that so the inverter/battery doesn’t “see” and EV load and won’t discharge when your car is charging. Photos of the setup on other threads

geoffreycoan cheers Geoffrey makes sense, I’ll delve into the comments and see what I can find thanks

Neal720
Both Zappi and Hypervolt can be used with solar. I have a Zappi (fitted by Octopus) which doesn't see the solor battery as the CT clamp is in the right place, and works well with IOG, but I don't use with solar, as it doesn't make economic sense currently with 7p import and 15p export.
However, Octopus have stopped the fixed 15p export rate, and it's now 'flexible'. It is still 15p but one wonders for how long? If there comes a point in the future where the 7p and 15p are reversed, then having the facility to charge by solar would be very worthwhile!

Thanks Tim, you and Geoff make very good points, it would be nice to have the option to utilise solar, as one time install, however understand practically in present day conditions it doesn’t make sense, also given the many complications with chargers installed on more complex systems than a home without solar/battery. I’d use giv energy to utilise the eco system or hive as there integrated mainly but both have issues themselves with aftercare unlike hyper volt. If I get an installer that knows systems well I’d be happy to utilise the solar otherwise play safe and have setups as described by Geoff and I’m guessing yourself.
I take it if the CT of the EV charger is above the inverter/battery does that mean then that on the giv energy app it wouldn’t see the load generated by the charger (sorry if this is a stupid question)
Many thanks for the reply

Neal720
The positioning of the CT clamp is important! On my Zappi install by Octopus, I did have problems as not many of their install team are aware of the problem with power being pulled from the solar battery. In the end it got sorted as as I'll explain below and with a photo.
In the white external electric meter box you have the mains fuse from the grid. The +/- tails coming out go into the meter. Then +/- come out and go to two separate Henley blocks (junction boxes). The CT clamp is fitted to the positive tail between the meter and the positive Henley block.
Out of the Henley blocks come 2 x positives from one of them, and 2x negatives from the other. One positive and one negative goes to the main house fuse box, the other positive and negative go to a separate fuse box which then feeds the Zappi.
It's actually fairly straight forward, and Zappi doesn't see the solar system at all and doesn't draw from the battery. I say that and have been caught out occasionally when exporting remaining battery to the grid in the evening ready to recharge at 11.30pm, and the IOG charging schedule has changed, so starts charging the car and then pulls my export into the car to supplement the grid. Doesn't happen often and if I notice it, i just stop the export!
I had to get the DNO to upgrade the house fuse to 100 amp as I was on 60 amp, which wasn't a problem with UK Power Networks.

TimHutchings I had to get the DNO to upgrade the house fuse to 100 amp as I was on 60 amp, which wasn't a problem with UK Power Networks.

I assume the CT clamp you are showing is the Zappi’s CT clamp and the inverter’s CT clamp will be somewhere on the Henley block going into the house.

Also to say that the DNO’s generally won’t upgrade house fuses to 100A any more, the national standard is 80A
https://commercial.nationalgrid.co.uk/downloads-view-reciteme/633928

This is not a problem because an 80A fuse can deliver 100A for about 4 hours

geoffreycoan
Yes, the Zappi's CT clamp is the black one shown in the photo. The inverter's is somewhere around the house fuse box.
When Octopus fitted the Zappi, the guy did upgrade the tails for a 100 amp fuse, but told me he wasn't allowed to change the main fuse as it is DNO property. Anyway, he said he would put in a request to have it upgraded. After a couple of months, nothing! So I contacted the DNO, and I did have to fill in a form listing the EV, solar installation, tumble dryer, dishwasher, A2A heat pump, induction hob etc, all the heavy draw items which could be on at the same, time. Anyway, they agreed to do it and a date was booked in 2-3 weeks later. A week before the appointment date, we started to get flickering LEDs in the ceiling and the airfryer fan started changing tone with its fan. Getting a bit concerned I rung the DNO the next day explaining the situation, and they came round about 4 hours later.
Turned out the mains 60 amp fuse in the meter cabinet hadn't blown, but had started to melt its casing quite badly.
Moral of the story. Make sure you have an adequately rated fuse as they obviously don't always blow when they should!

TimHutchings
Have you considered moving that CT clamp in picture below the Henley onto the Zappi tail so the battery does't see it?

Thanks Tim, all this is a learning curve for me and also informative, especially when an installer does come, I can at least know some of the jargon to explain my wishes/concerns.

Neal720 I take it if the CT of the EV charger is above the inverter/battery does that mean then that on the giv energy app it wouldn’t see the load generated by the charger

Correct.

TimHutchings Zappi doesn't see the solar system at all and doesn't draw from the battery.

I'd say that was backwards: the solar system doesn't see the zappi. The zappi can't pull from the battery: what happens is that, if the inverter sees the power drawn by the zappi, it discharges the battery to try to cover the load.

The zappi does see the solar, in the sense that if you are exporting excess solar, you can still choose to have the zappi divert it into the car. Indeed you have to also configure the zappi to ignore solar if you don't want to divert solar into the car.
(The zappi cannot distinguish export of excess solar from export of battery.)

TimHutchings Moral of the story. Make sure you have an adequately rated fuse as they obviously don't always blow when they should!

In that article I linked it explains more about how the fuses work, they are slow blow thermal fuses so they will blow with a high current draw for an extended period of time. That’s why they are standardising on 80A house fuses not the 100A they used to fit (I have a 100A as well), its because they don’t blow immediately at 100A, only after an extended period of time.

Sounds like that was what was happening with yours, it will sustain more than 60A for a period of time, but of course start melting in the process. As you say, the master fuse is DNO property, only they can touch it.

geoffreycoan I would suggest you get an EV charger that is compatible with Octopus Intelligent Go

But not the Ohme Pro because instead of using Octopus to schedule the IOG slots, the Ohme app does it and the Ohme app has no way to stop your GE battery emptying into the EV. The Ohme app is also flakey.

TimHutchings Moral of the story. Make sure you have an adequately rated fuse as they obviously don't always blow when they should!

Hi Tim

From a discussion on an Octopus forum about this issue with decay/degredation of legacy cut-outs https://www.bbc.co.uk/news/articles/cgrqlnlp4w2o

EDIT: sorry I see @geoffreycoan has already posted most of what comes next...

I happened upon and posted a useful document that mentions just how long it takes to 'blow' a beefy fuse and why 80A is often now being fitted as standard -
https://commercial.nationalgrid.co.uk/downloads-view-reciteme/633928

I quote "....because an 80A fuse is capable of permitting the flow of up to 100A for up to four hours."

My heavily loaded 60A was running at temperatures of 60+ degrees 3 times a day. Even when the installer had followed DNO and design guidance to the letter and set everything correctly.

DD
Correct DD! Sorry I was a bit tired when I posted. Yes, the Inverter can't see the Zappi, but the Zappi does see the solar system or I wouldn't be able to use solar to charge the car if ever I decided that was what I wanted to do. The way I have mine set, is that it sees whole solar system as one item in the Zappi (MyEnergy) app, not what is going on within that system, but just sees the energy coming out or going into that system.
There's a setting in the Zappi I changed, which allows you to set the level of solar export to the grid before the Zappi will take any surplus. I set it to 6kW, as I have a 5kW inverter, so it never reaches that level.
However, electric can only travel in one direction from the grid, so as I mentioned in an earlier post, occasionally, if I'm exporting from the solar battery in the evening to empty it, and Octopus decide to charge the car by changing the schedule I am expecting, then the 7kW going to the car from the Zappi comes from the grid and my export. If I notice, I just stop the export.

geoffreycoan
Thanks Geoff! Yes, I read the link and there's some useful info there.

mole
It's fine as it is, otherwise I'm guessing the Zappi wouldn't be able to use any excess solar, if at some stage, I decided to use solar for the car. I did explain in a follow on post to DD. Thanks for your input.

alan_johnston Is your setup similar to what Tim and Geoff explained, in that the EV charger is set just after the meter so it ‘it doesn’t see the inverter/battery’? Wondered why the charger would pull from the battery if this is the case?
I’ve contacted installers that fit solar systems and EV chargers, hoping they are more aware of these issues, and may have a bit more knowledge (maybe) than the EV charger only installer.

This is our EV/Solar setup.
The lower CT clamp is for the EV charger.
The second one (between the two brown connection boxes) is for the GE solar
There is a third CT clamp in our distribution box on the cable that goes into the solar RCBO for the Zappi to sense the Solar output.

Really helpful, electrics isn’t my bag at all hence all the daft questions, so does your system have a battery aswell or just the solar? By the GE Solar you mean inverter/battery? All helpful and appreciative, I feel sorry for whichever installer comes with alm my questions!

Yes I have a Gen 2 5Kw inverter and 2 x 9,5Kw batteries. I don't let the batteries export with my EV plugged in as it used the battery and or export of solar to charge the car. I schedule the export without the car plugged in as I don't need to charge my EV every day.

Neal720 My EV charger is set so that it the inverter sees it as part of the house load.
So when the EV charger starts up, the inverter will try to match it using solar+battery.