Cart before the horse? (EV charging)

@Lisa Miles  

OY ! This is a wiring matter. Can it be moved back please.

Mike.

At least it didn't go to General Chat… 

Clive

I'm some years retired from electricity distribution but there seems to have been little policy progress or recognition of the cost impact of rebuilding distribution systems to handle EVs.

After Diversity Maximum Demand (ADMD) is the aggregate demand across a group of users (20 - 30 houses+ with an increase for smaller groups) and usually lower than most would guess at 3-4 kW/house. I've not come across distribution companies setting a maximum demand for each consumer beyond the cutout fuse rating.

In old money 80A is just a bit short of 20kW. Street cabling has a cyclic rating for several hours but service cables in more a matter of minutes especially if run in an insulated wall cavity.

Not relative to your initial choice of one car how many houses will have a single car to charge and how long to charge a discharged Tesla at 7kW? (or a car, a couple of tractors and an HGV).

In addition to cable ratings and reinforcement will additional distribution substations have to be dropped into the network with all the politics of siting in a developed area?

Solutions will need electricity supply policies and costs but also social adjustments, better public or shared transport and some re-distribution of work.

To go back to the question it's might be best to fit your 7kW unit before the waste hits the, possibly still rotating, fan.

Thanks Mike. I think too that the way to go is to get a Charge Point installed or at least approved ASAP.  I have located the appropriate form for the DNO on the Energy Networks website:-

www.energynetworks.org/assets/images/Resource%20library/Single-Electric-Vehicle-Charge-Point-and-Heat-Pump-Installation-Application-Form.doc The form being:-

 www.energynetworks.org/assets/images/Resource%20library/Single-Electric-Vehicle-Charge-Point-and-Heat-Pump-Installation-Application-Form.doc 

The area which confuses me slightly is they ask in Section C - Electricity Supply Details for the Max Demand of the Premises and also the Supply Capacity confirmed by the DNO and in E - Equipment to be installed, they ask for Maximum Current Demand of proposed equipment.

And then on page 1 Maximum Demand is defined as the existing MD plus the new equipment, stating it separately would make more sense? Having EV Charge Points, Heat Pumps and Vehicle-to-Grid all on the same form does not help.

A quick totting up of our existing appliances (with no diversity) puts me at just over 90A we have an 80 A fuse in the 100A rated cut-out.  In normal day to day usage, I don't think that we would never get to 90A unless I tried hard!

But that seems to be the figure they want to work with, plus of course the 7 kW of the Charge Point.

Clive

I had a 7kW charger installed a few months ago. I used a local electrician who puts these things in all the time so likely to go smoothly - it did. He told me the DNOs had just started asking about the new loads as they were planning their network upgrades etc + the issue of control of loads in future. He assessed first, filled in all the forms, did the tests etc (I am not a sparky of course). Good luck, hope it goes well.

Sparkingchip: 
 

and there was me assuming that the ancient mariner was running his fleet on heavy fuel oil ?

He does! Well in part at least. Our 23 year old MX-5 is obviously petrol, but today received in the post a replacement V5C Registration Certificate following us putting our Mitsubishi Outlander's Reg No on Retention for a new EV to replace it. 

On page 2 of the V5C - Vehicle Details, under "P3: Type of Fuel" it states: “Heavy Oil” !

Clive 

I should hang in there ancient mariner , the home charger idea may be a big mistake for domestic grid loads , 23mn cars and the load is impressive at any time of day , and it could be a big mistake shoving charging onto night loads , even though i initially backed night time charging my self , at the moment for EV use some has got to get the correct calculator out . I can see why the rapid charge thinkers have the edge on this , but it depends on the battery and how it wears with rapid charging , some EV owners could be very upset if they find that after 5 yrs use of the rapid charger , there battery takes only an 80% charge , due to degradation, through using high rate charging.

The lack of complete recycling is problematic , but I think some batteries being installed now will not be the ones we have in a couple of years , and if they just make batteries that don't recycle then someone will have the cost , and it would benefit the car makers to be able to recycle batteries , if the 5yr degradation barrier cannot be improved .

Even GM have now got battery problems , so even the big car makers can make poor choices. 

I dont think Tesla will win the battery race , but I have to admit the new model 3 motor is pretty amazing 96% claimed efficiency .  

Hi Mike Brown 

I couldnt agree with you more , people are putting out all sorts of scenarios on becoming fully electric , and the cable running up the street , at the moment and with inefficient housing , just will not do it .

Hopefully some different thinking on its way , to think about the right trajectory soon.

Helios: 
 

I should hang in there ancient mariner , the home charger idea may be a big mistake for domestic grid loads , 23mn cars and the load is impressive at any time of day , and it could be a big mistake shoving charging onto night loads , even though i initially backed night time charging my self , at the moment for EV use some has got to get the correct calculator out . I can see why the rapid charge thinkers have the edge on this , but it depends on the battery and how it wears with rapid charging , some EV owners could be very upset if they find that after 5 yrs use of the rapid charger , there battery takes only an 80% charge , due to degradation, through using high rate charging.

The lack of complete recycling is problematic , but I think some batteries being installed now will not be the ones we have in a couple of years , and if they just make batteries that don't recycle then someone will have the cost , and it would benefit the car makers to be able to recycle batteries , if the 5yr degradation barrier cannot be improved .

Even GM have now got battery problems , so even the big car makers can make poor choices. 

I dont think Tesla will win the battery race , but I have to admit the new model 3 motor is pretty amazing 96% claimed efficiency .  

Many manufacturers offer 7 or 8 year warranties on their batteries.  They wouldn't do that if the batteries started failing after 5 years.  The cost of the warranty replacements would wipe out any profits on the cars.

A reputable spark will be able to determine if your house load is able to support the 7kW charger on an 80A fuse (but for me, probably yes), and do the DNO paperwork too - if this is done beforehand then the DNO is able to say if the supply is sufficient. The Zappi is a good fit too as it has the load management as said by others. Clamp meter or data logger will also determine max load but you can usually estimate it pretty easily.