EV charger and later fitting solar

[ModMan]

I've read the "Which charger" thread and the Hypervolt looks like a contender. I filled out the application form and submitted photos, they gave me a call and said that they would/could wire the charger straight into the electricity meter on the outside of the house and just run the cable round (I'd need to do a bit of brickwork/pavingwork myself to get the cable past the front door but that's another matter)

Since it's a long weekend and I can't ask them before Tuesday .... Would that type of install still be ok if I went with solar (perhaps with a battery) later this year? Would I have to get the charger rewired into a consumer unit or something if their method isn't compatible with a solar setup. Does anyone know or have any advice before I call them and perhaps some solar installers next week?

[Paul Drawmer]

I think (therefore I don't actually know) the charger installation will require a sense lead to the incoming supply to detect the excess PV power available to use at the charger. If the installation is completed as if your solar panels were present, all would be OK, just the charger would never work in use excess pv mode.

BTW why Hypervolt v Zappi?

not very informative thread
https://www.speakev.com/threads/hypervolt-vs-zappi...

[gmaz]

Installers often add an additional small consumer unit specifically for the solar and EV charger so as not to disrupt your existing wiring.

I've no experience with Hypervolt, but my Zappi works well with solar and battery.

[No ideas for a name]

ModMan said:

...they gave me a call and said that they would/could wire the charger straight into the electricity meter on the outside of the house and just run the cable round

Assuming they mean directly in to the meter cupboard...
In my opinion, it is a poor way to install.
This is based on the fact that the meter box is reserved for the DNO and metering equipment.
An end-user isn't supposed to put any equipment in there with the exception of an isolating switch.
You will probably get away with it, but it might lead to problems in the future when the DNO's kit or meters get changed and no longer fit.

I am lead to believe many installs are done like this - it doesn't make it right.

Note, this is different that the argument for a separate CU - that can be fine, it just depends on location.

[ashenfie]

Solar and EV charging are two separate thinks, if you think you solar cells are going to charge you car then forget that. The EV will need a minimum charge that the solar cell are not going to reach especially at night after work. If you want to get money back by sell electricity to the grid that that has nothing really to with saving an EV or not.

[Paul Drawmer]

ashenfie said:

Solar and EV charging are two separate thinks, if you think you solar cells are going to charge you car then forget that. The EV will need a minimum charge that the solar cell are not going to reach especially at night after work. If you want to get money back by sell electricity to the grid that that has nothing really to with saving an EV or not.

If the solar panels are producing power and the EV is being charged at the same time, then the solar power contribution reduces the demand from the grid at that time.

An EV charger designed to take advantage of solar will limit the vehicle charge rate to make maximum use of the excess solar power. Nobody suggested it would work at night. Obviously it's going to be of more benefit where there's an EV on the drive whilst the sun is shining.

[ashenfie]

That not what will happen. While as you say a small amount of power might sucked from the solar,The ev will take charge from the grid and charge at normal rate. Solar alone does not have the min power rating required by most ev’s

[GT9]

ashenfie said:

Solar and EV charging are two separate thinks, if you think you solar cells are going to charge you car then forget that. The EV will need a minimum charge that the solar cell are not going to reach especially at night after work. If you want to get money back by sell electricity to the grid that that has nothing really to with saving an EV or not.

Unless of course the OP adds a static battery to store the solar energy, as stated in his opening post.

A 4 kW solar array will produce enough energy to power an average EV for around 8000 miles per annum.

The size of the static battery will depend on how often the OP is willing to discharge it into his EV.

Anyway, isn't this the bit where you suggest converting the energy to hydrogen and buying a fuel cell car....

[gmaz]

ashenfie said:

That not what will happen. While as you say a small amount of power might sucked from the solar,The ev will take charge from the grid and charge at normal rate. Solar alone does not have the min power rating required by most ev’s

This is utter bks.

Here is my graph of solar charging on a sunny day last week using a Zappi..




Yellow - the generation from the panels
Orange - export to the grid when my car wasn't plugged in between 12-3pm
Green - consumption by the house/EV. You can see the two green blocks of EV charging giving me about 7-8kW over the day
Grey - below the line is the house battery charging as that has priority over the EV charger.
Red - below the line is power taken from the grid, as you can see there is barely any except for when I'm using the kettle, oven etc.

Minimum EV charge rate should be 1.1kW so the power provided by the panels @ 3.5kW easily exceeds that

Edited by gmaz on Saturday 7th May 10:56

[GAVGOLF]

Solar will contribute towards charging the car but typically will not be able to provide the full 7kW of power that you would probably like. The constraining device is the pv inverter which for most houses is likely to be limited to 3.68kW.

[Paul Drawmer]

GAVGOLF said:

Solar will contribute towards charging the car but typically will not be able to provide the full 7kW of power that you would probably like. The constraining device is the pv inverter which for most houses is likely to be limited to 3.68kW.

And the solar EV charger will limit the EV charge rate to use the PV output. (or PV + battery as shown above)

If the EV is away from home all day, there's less opportunity to use the PV power; but for those with an EV on the drive during the day it makes sense.

[ashenfie]

gmaz said:

ashenfie said:

That not what will happen. While as you say a small amount of power might sucked from the solar,The ev will take charge from the grid and charge at normal rate. Solar alone does not have the min power rating required by most ev’s

This is utter bks.

Here is my graph of solar charging on a sunny day last week using a Zappi..




Yellow - the generation from the panels
Orange - export to the grid when my car wasn't plugged in between 12-3pm
Green - consumption by the house/EV. You can see the two green blocks of EV charging giving me about 7-8kW over the day
Grey - below the line is the house battery charging as that has priority over the EV charger.
Red - below the line is power taken from the grid, as you can see there is barely any except for when I'm using the kettle, oven etc.

Minimum EV charge rate should be 1.1kW so the power provided by the panels @ 3.5kW easily exceeds that

Edited by gmaz on Saturday 7th May 10:56

Hard to really know but it's to suggesting as it rather confusing graph, Some of the colours have no keys and I guess down is "bad power" and "up is PV power"?

but basically what I am saying that the Gid tops-up the PV, so basically you have to consider what peak sun light would be available to provide worth while charging.

[OutInTheShed]

gmaz said:

This is utter bks.

Here is my graph of solar charging on a sunny day last week using a Zappi..




Yellow - the generation from the panels
Orange - export to the grid when my car wasn't plugged in between 12-3pm
Green - consumption by the house/EV. You can see the two green blocks of EV charging giving me about 7-8kW over the day
Grey - below the line is the house battery charging as that has priority over the EV charger.
Red - below the line is power taken from the grid, as you can see there is barely any except for when I'm using the kettle, oven etc.

Minimum EV charge rate should be 1.1kW so the power provided by the panels @ 3.5kW easily exceeds that

Edited by gmaz on Saturday 7th May 10:56

So on a good day, when it happens to make electricity you happen to need, it saves you about £2.50
Some days it won't generate that much electricity, some days you won't need (or be able to store) the electricity when it generates it.

For the purposes of putting a peg in the ground, let's say 300 'good days' a year, I think that's about the max for a sunny place in the UK.

Potential saving £750 a year.

My view is that home batteries need to get a lot cheaper.
I think it is possible that they will get lots cheaper, I think early adopters need to be getting payback in say 5 years, because by then, it is feasible the battery price will have dropped hugely.

I know a lot of sailing people (online at least) with serious off-grid inclinations. You can get 2000 or maybe 7 years cycles out of a Trojan lead acid battery, discharging to 50%, which is about £300 per usable kWh. Some people are talking of LiFePO4 getting into that price arena before long. The cells are only part of it, you need a much better control (BMS) setup than you do with lead acid.

Like the boat community, some people get value out of being independent or less dependent of the grid of course, the sums are different if its saving you a big UPS and a petrol generator .

Personally my car usage is not a convenient 30 miles regular very day, it's more like 0, 40, 0,10, 120, 0, ......200, 60, 200,0....and the high miles days it is often off the drive for a day or two.