Hi guys. I am about to start 1st fix electrics and just wanted to check if there is anything I should be considering in terms of wiring to future proof for use of battery storage of PV power? I assume that these new Tesla type power packs use an inverter to convert DC back to AC so that the standard house wiring can use utilize the power?

Also, do electric car recharging points run off standard ring main or do they need higher amp direct wiring?

Cheers.
Phil

I would plan for 16 A for car charging

Re battery storage, I think charge and discharge at 240 V. Likely 13A max

Car chargers I've fitted (only 2) were 7.2kW so 31A
depends on run, I'd stick a 6-10mm T&E in to be on the safe side

Powerpack, a 4mm spur to garage / utility would cover a lot

Most electric car batteries are currently tiny. I expect that 7kW chargers may in the end be quite limited.

If you look at the Tesla, with electric range to be a normal car, Tesla's supercharger quick chargers are either 11kW or 22kW - which is 50A or 100A at iirc. Eventually we will want something closer to that at home if we are eg charging a couple of electric cars with realistically size batteries every day.

I'd say allow:

* Space in your garage or plant room.
* Which is accessible and practical for parking 2 cars to be charged.
* Make it secure in some way - so that oiks can't cut your cables easily at 2am or so that your garage security isn't compromised. This is important given the cable size and copper thieves.
* Provide for lots of Consumer Unit space, and perhaps install a subsidiary consumer unit with a cutoff switch to cope with everything you can think of in the appropriate place.
* Space for DC cable runs.
* Allow more space than you think - some pesky engineer will invent something useful you haven't thought of yet.

I'm gradually doing my setup, and they've just put two Inverters in for the solar array, on top of the 7kw charging gubbins that went in last year, and the garage is filling up. Just need the Tesla, now!

Ferdinand

I can see it. Stock broker no 1 comes home, plugs his tesla in, the lights dim. Next one comes in the lights dim a bit more. Stock broker no 10 comes in the lights go out.

Taking 100A from domestic distribution on a large scale is a completely ludicrous idea. The distribution system is built on the idea of diversity, i.e an individual consumer might have a current draw of 40-60A occasionally, but it will only be for a few minutes; the average household draw will be something like 2-4A. Every household drawing 100A for several hours just isn't going to happen.

Your PV system won't contribute to that in a significant way either. My massive (15kW) solar array averaged 7.6kWhr per day last month, not enough for our normal electricity consumption let alone an electric car. It did 61kWhr a day in June, which would do half a charge, but how many EV owners are going to have room for an array that size?

What have electric cars got to do with preparing for PV storage anyway?

Hi billt,
We have about 50,000 EV's at the moment so with most at 3 kW and some domestic ones at about 7 kW not really going to be a problem for a number of years yet. But not everyone will be maxing out power by any means. Average 12,000 miles/year needs 3000 kWh per year thats 8.3 kWh per day. So some planning needed but easily solvable. I think that tariffs will be coming in to give economic incentives to charge when it's best for the grid.

If every house hold plugged in a 3 kW kettle at the same time then that would be 3 kW x 30,000,000 that's 90 GW thankfully statistically it's impossible.

Richard