EV charging cable length and energy loss

_Sam_

Apologies if this has been discussed before! We have an electrician coming next week to install an EV charger, and there will be a fair bit of cable due to the distance between the mains box and the charger maybe 16-18meters of cable. I've just read somewhere that the longer the cable the more significant is the energy loss, which can be improved slightly by a thicker cable. 

I'm wondering if anyone is in a similar situation, and may have done the math on this? I'm terrible at math and don't understand electricity much. Thinking would using a 10mm cable be overkill or a good idea given the length of the run? Will ask the installer when he comes to measure, but just hoping to see what other people have done.

A 10mm cable Im thinking about: https://www.toolstation.com/doncaster-cables-ev-ultra-ev-charger-cable/p53180

alan_d

The electrician will take care of the energy loss calculation and put in a suitable cable. Leave it to him.

Keep_pedalling

The difference in voltage drop over that sort of distance between 6mm and 10mm is going to b3 about 2v so 10mm is probably over kill.

Hoe close is the meter box to the EV charging point position? Best practice these days is not to supply from the CU but to install a separate mini CU adjacent the meter.
 

_Sam_

The installer will indeed be putting in a separate mini CU, but the problem the charger is on the other side of the bungalow from the meter box. Electrician suggested going up in the loft from the meter box, then across and down the other side to the charger. The span of the bungalow is about 12.5 meters plus up and down.

Miser1964

In addition to the cable run, all new home EV chargers must have a network connection and they can be picky on connecting to a weaker home WiFi 

_Sam_

Keep_pedalling said:

The difference in voltage drop over that sort of distance between 6mm and 10mm is going to b3 about 2v so 10mm is probably over kill.
 

I found a calculation done by someone on a 10m cable (not sure if correct but from an electricity site discussion!) 


I based the calculations around 10m of T&E with a 7kW EV charger as a load for 8 hours a day with a full charge for 200 days of the year at 15p per kWh.
A 6mm cable for a constant 7kW load has a cable energy loss of 60.4W running at 46.5 degrees C. So 7.25p per day x 200 days = £14.50
A 10mm cable for the same load and duration has a cable energy loss of 34.6W running at 38.7 degrees C. So 4.15p per day x 200 days = £8.30


Nearly double loss of 6mm at 60.4W as opposed to 10mm at 34.6W, if correct?

Ectophile

Miser1964 said:

In addition to the cable run, all new home EV chargers must have a network connection and they can be picky on connecting to a weaker home WiFi 

But you can now get cables for chargers that include a network cable in them, for wired connections.