On 26/11/2020 08:00, Andy Burns wrote:
F wrote:

We may be in need of a 7kW EV charging point in the fairly near future.

Anyone got any advice on* makes, installers (I assume it's not DiY to
a competent DiYer),

To qualify for the grant they have to be installed by someone on the
scheme.

what to avoid,

Rolec?

what to ensure? It's all new to me.

There are specific requirements about earthing for EVs, possibly
requiring a separate earth rod, particular RCBO type and carefully
keeping apart the house earth and car earth.

Bugger. Does that mean I would need two separate supplies for EV
and normal garage power (which might include an Air-water heat pump
at some point) ?

At the moment my garage is detached and separated from the house by
a metre wide path and the original builder? ran power into the garage
via some of that TUFF cable (not swa), 'professionally' installed inside
a 4 foot length of yellow plastic gas pipe, buried under the original
concrete path and curled up 90 degrees at each end. The house side
is clipped to the outside wall and goes through the cavity wall and into
the back of a single socket connected to the ring main via an FCU.
Garage end has another 13 amp FCU feeding lights and single socket.

I am about to replace the gas pipe with some 25mm black conduit but if
I need two separate cables then some 38mm stuff might be better.

The cable that Doncaster sell has 2-core or cat5E signal cable in the
same sheath, but how would the cat5e be 'split out' so that it connects
to the house network ?. This must be cutting the sheath of the main
cable and pulling the cat5e out before the cable enters a consumer
units or junction box ?.

I've been waiting for Adam to install one so he can illuminate us.

There are now several chargers that do all the earth handling
internally, and might be OK for DIY e.g.

https://myenergi.com/product/zappi

Look at a couple of EV videos on youtube by John Ward or Artisan Electrics.

On 26/11/2020 16:34, Andrew wrote:


I've been waiting for Adam to install one so he can illuminate us.

I fitted one on Monday.

We are OLEV registered and can organise the grants. But you need to
buy/order a car before you can apply for the grant.
Work can be done without a grant.
As to what is needed I really would have to make site visit as it is not
as simple as a new shower circuit.

--
Adam

On 26/11/2020 17:22, ARW wrote:
On 26/11/2020 16:34, Andrew wrote:


I've been waiting for Adam to install one so he can illuminate us.

I fitted one on Monday.

We are OLEV registered and can organise the grants. But you need to
buy/order a car before you can apply for the grant.
Work can be done without a grant.
As to what is needed I really would have to make site visit as it is not
as simple as a new shower circuit.


I'm near the South Coast, a bit too far I suspect.
I was hoping for elaboration of the need for a signal cable,
which the Doncaster cable has built in (2-core or cat5e).

Did you have to connect these up ?. Does the energy supplier
have the right to stop an EV car being charged by remote
control (in times of supply stress).

Andrew wrote:

I was hoping for elaboration of the need for a signal cable,
which the Doncaster cable has built in (2-core or cat5e).

That's intended for smart chargers such as the zappi, so it has one or
more pairs of data cable to connect to one or more current transformers
(e.g. on the mains feed, or solar feed)

Of course as it's insulated to mains levels, you *can* use it as cat5
cable, I'd say gland it off into a box, then separate the data and power
wires off from there.

On 26/11/2020 20:31, Andrew wrote:


I'm near the South Coast, a bit too far I suspect.
I was hoping for elaboration of the need for a signal cable,
which the Doncaster cable has built in (2-core or cat5e).


Some chargers have a current sensor on a meter tail, which senses the
total current being consumed in the house and throttles back the
charging current if there's a risk of exceeding the supply capacity. The
signal cable to which you refer is almost certainly intended for that.
--
Cheers,
Roger

On 27/11/2020 15:18, Roger Mills wrote:
On 26/11/2020 20:31, Andrew wrote:


I'm near the South Coast, a bit too far I suspect.
I was hoping for elaboration of the need for a signal cable,
which the Doncaster cable has built in (2-core or cat5e).


Some chargers have a current sensor on a meter tail, which senses the
total current being consumed in the house and throttles back the
charging current if there's a risk of exceeding the supply capacity. The
signal cable to which you refer is almost certainly intended for that.


In the absence of a power supply problem would the ev charging be at a
constant rate or does the battery dictate what power it can absorb and
turn it down?

On 27/11/2020 16:43, AJH wrote:
On 27/11/2020 15:18, Roger Mills wrote:
On 26/11/2020 20:31, Andrew wrote:


I'm near the South Coast, a bit too far I suspect.
I was hoping for elaboration of the need for a signal cable,
which the Doncaster cable has built in (2-core or cat5e).


Some chargers have a current sensor on a meter tail, which senses the
total current being consumed in the house and throttles back the
charging current if there's a risk of exceeding the supply capacity.
The signal cable to which you refer is almost certainly intended for
that.


In the absence of a power supply problem would the ev charging be at a
constant rate or does the batteryÂ* dictate what power it can absorb and
turn it down?

They are the same thing. What limits charge current is usually heat. Eye
squared Arrr, probably a temp sensor in the pack as braces, but the belt
is constant permissible charge current. As the voltage rises to 'fully
charged' the charger will simply switch off..


--
If you tell a lie big enough and keep repeating it, people will
eventually come to believe it. The lie can be maintained only for such
time as the State can shield the people from the political, economic
and/or military consequences of the lie. It thus becomes vitally
important for the State to use all of its powers to repress dissent, for
the truth is the mortal enemy of the lie, and thus by extension, the
truth is the greatest enemy of the State.

Joseph Goebbels

On 27/11/2020 16:57, The Natural Philosopher wrote:
They are the same thing. What limits charge current is usually heat. Eye
squared Arrr, probably a temp sensor in the pack as braces, but the belt
is constant permissible charge current. As the voltageÂ* rises to 'fully
charged' the charger will simply switch off..


So these EVs with range extender engines will have the engines running
at constant power whenever they need to charge whether the car is moving
or not?

AJH wrote:

In the absence of a power supply problem would the ev charging be at a
constant rate

the EVSE* will tell the car how much it is allowed to take, this may be
a fixed setting, or it may vary depending on consumption elsewhere in
the house and/or your own solar generation.

or does the battery* dictate what power it can absorb and
turn it down?

The in-car charger will determine how much it wants to take, dependant
on how much it is allowed and things like battery temperature.



* the box on the wall that most people refer to as a 'charger' isn't
really, it's just a glorified relay and a bit of signalling

On 26/11/2020 16:34, Andrew wrote:
On 26/11/2020 08:00, Andy Burns wrote:


There are specific requirements about earthing for EVs, possibly
requiring a separate earth rod, particular RCBO type and carefully
keeping apart the house earth and car earth.

Bugger. Does that mean I would need two separate supplies for EV
and normal garage power (which might include an Air-water heat pump
at some point) ?


Not necessarily. The earthing requirement is for making sure that your
car bodywork can't become live if the supply earth is lost and another
fault occurs at the same time. This mainly applies to TN-C supplies
where earth and neutral are combined, and isn't a problem with TN-S
supplies. In any case, many EV chargers now have built-in PEN
protection, which immediately disconnects them in the event of such a fault.

As to whether you need a separate supply cable, that will depend on the
capacity of the existing cable. There seems to be tendency to use
oversize cable to minimise the voltage drop and, perhaps, provide
future-proofing. So, if the existing cable is less than 6 mm^2, it might
be marginal.
--
Cheers,
Roger