Charge from solar???

[ChangoMutney]

It depends on your setup. With a Zappi charger, you can tell it to only use solar to charge the car, or some grid mix in with a percentage you specify. If you select 100 percent solar, as soon as you get to 1400W excess (minimum the car can take), it will put it in the car. We have 7.7Kw solar, so car input varies between 1.4 and 7.2Kw depending on how much we generate. With 4kw in the UK at this time of year or earlier its unlikely you would charge your house battery, run your house and still have much to put in the car. As the days get longer, you will be able to do this but your charger has to be capable of scaling what it delivers to the car to match your excess solar. Not all chargers will do this. You could use reduce charge current, in car setting to try and stay within your solar budget but this is not going to stop when clouds come over or increase when you have maximum generation. You really need something like a zappi, which can also control water heating and house battery charging too and prioritise whatever to want.

[RichR]

Also Zappi allows you to schedule a charge when you're on off-peak electricity. There's quite a lot of options, and it can get very confusing as to what to set - but it's very dependent on how you use your house and car, so not easy to give a one-size-fits-all recommendation for settings.

I've got solar+10kWh battery+heat pump+Zappi being fitted in a couple of weeks time. I reckon it'll take us a few years to work out what to set on the Zappi, the inverter/battery control and heat pump to get the best from the system. Initial thoughts are to set it to keep the house battery topped up from off-peak grid overnight, then prioritise solar charging it during the day. Any excess can be detected by the Zappi and go to the car (if it's plugged in), otherwise the hot water. Sending it to the grid is the last resort. In summer we may reduce the amount taken from the grid overnight, we'll have to see how much the panels make. I don't charge the car that often, so it's not a guaranteed place to dump electricity. However once my wife changes to an EV that may change.

And yes, I have read the manuals for the Zappi, inverter, batteries and heat pump already. So I'm not guessing or expecting it to do things it can't

[foot tapper]

When people talk about charging from solar, what exactly is the configuration they are referring to?

A cool sunny day might give you 3-4kW peak from PV panels.
Are you somehow able to route this directly to the vehicle?
Can you prevent other sources - grid, battery storage - chipping in as well as the solar?
And if you can charge directly and solely from solar, why would you want to charge so slowly?

I suspect I'm missing something here.
I've got solar PV, storage batteries, and grid as power sources.
I've configured the inverter to prioritise supplying the house load, charging the batteries, and exporting to the grid. It simply sees the car as part of the house load. So if I had, say 3kW solar being generated and a wholly imaginary 0kW house load. If I then switched on a dishwasher, no problem - my 3kW should cover that. But if I also switch the car charger on that's way over the solar supply. So I start drawing from batteries and/or grid. How can you separate the solar electrons from the rest?

We have a myenergi Zappi charger as part of our home installation. By setting it to eco+ mode, it only diverts surplus solar into the car.
The installation also has CT clamps on both the solar PV inverter's output and the Tesla Powerwall battery.
As a result, the myenergi software reliably identifies when we have a surplus of home generated electricity and distinguishes between surplus solar PV on the one hand and battery export on the other.

Hence, we can reliably charge our car with up to 7.5kW of surplus solar PV electricity, knowing that this is not battery export or from the grid.

At this very moment, the house is using 400W, car's battery is full so Zappi is drawing nothing, the Eddi is diverting 2.7kW into the hot water tank and the remaining 3.8kW is being exported to the grid. The 8kW solar array is generating 6.9kW.

Hope this helps.

[FatOldSun]

It's the first full-on sunny day since we got solar panels installed. I left the Enyaq plugged in this morning and cycled to work, hoping to get some nice bonus electrons into the car battery. I switched on solar matching on my charger, and I started the charge at around 11am, and then it stopped after a couple of minutes. I switched the setting on the app from preferred times to instant, and the charge restarted and lasted till about 12.30pm, and now it's stopped again. It was pumping about 3.5kW into the car at the time. The app was then saying that the cable was unplugged, even though it's not. Now, the app says that the charging status in unavailable. Any idea what's happened and whether I can fix it remotely?

[Walter Eagle]

All - thanks for the responses on solar charging.

Tinkered a bit with both car and Project EV charger settings.

Putting the Enyaq to reduced current setting has it trickle charging at about 2kW at present. The total house load is that plus washing machine, dishwasher, fridge, freezer, and grid export is only a couple of hundred watts (house storage batteries are already full.)

I had to knock the Project EV charger off timed overnight charging to provide instant charge. But that can be changed back as daily demand and surplus require.

There are just so many variables to control!

[MikeJL]

I’m paid £0.12 per kWh by Scottish Power under the Smart Export Guarantee for excess solar power & pay £0.075 to Octopus for off-peak power overnight. So I’m better off charging the car at night & allowing excess solar power to go to the grid during the day.

If you have a feed-in tariff then I believe you are paid for a fixed percentage of your generation regardless of what is sent to the grid, so all solar power is effectively free & it makes sense to use as much as you can.

[ComicGeek]

The Project EV charger is pretty useless - I found the solar eco mode worked for a few minutes until a cloud caused the PV generation to drop, and then the charger needed to be manually reset to start again, was only good for full blue sky days.

The Eco+ mode was better, but even then there were times when it was drawing from the grid to achieve the constant rating. At times that was more expensive than just waiting for my cheap Octopus Go night time rate, so fairly pointless.

In the end I gave up and just used the night time charging. When I got our batteries installed I could control it better, as it didn't matter if I was using stored PV generation as well as instantaneous PV generation - the battery losses are better than just exporting it to grid.

Ultimately I ripped out the Project EV charger as it would constantly loss Wi-Fi connection and the pre set charging wouldn't work. Also wouldn't communicate well with the Enyaq, in that I had to start charging, then turn it off before I could set the pre set charge time - do you have this problem?

[HairyCowMan]

I’m paid £0.12 per kWh by Scottish Power under the Smart Export Guarantee for excess solar power & pay £0.075 to Octopus for off-peak power overnight. So I’m better off charging the car at night & allowing excess solar power to go to the grid during the day.

If you have a feed-in tariff then I believe you are paid for a fixed percentage of your generation regardless of what is sent to the grid, so all solar power is effectively free & it makes sense to use as much as you can.

That's correct. I'm on a feed-in tariff & I get paid a generation rate & also a cheaper exporting rate for 50% of the amount I've generated regardless of whether I've actually exported anything or not. This was one of the reasons I bought an EV as effectively during the summer months I'll be able to put any excess generation into the car & get paid for it. Winner Winner, Chicken Dinner

[Walter Eagle]

The Project EV charger is pretty useless [ ...]

[ ... ] so fairly pointless.

[ ...] it would constantly loss Wi-Fi connection and the pre set charging wouldn't work. Also wouldn't communicate well with the Enyaq [ ... ]

Wow. Thanks for the damning verdicts on my choice of charger. I hadn't realised what a useless, pointless device it is. (OK - add in the pretty and fairly modifiers).
I'll stop using it immediately as it's so bad.

[orrery]

There are 2 issues here:
1. The Enyaq (and I presume ID3 and ID4) before software V3 will see any on/off from the charger as being a charger fault and stop charging. This prevents the use of super Eco mode. I had to use the not-so-Eco mode where it always charged at 1.4kW, but this risks charging from peak rate leccy if there are clouds.
2. Charging from solar means that the car has to be sat at home when the sun's out, when you should be driving it. There's a lot to be said for using a cheap overnight tariff to charge the car and let the solar offset the expensive peak rate. Anything else requires more investment, such as a more expensive charger, or large batteries.

The above is good advice, but it doesn't mean I follow it - I have to have the fancy charger and the batteries etc. Will I get my money back on that investment? Maybe, maybe not.