Home  5  Books  5  GBEzine  5  News  5  HelpDesk  5  Register  5  GreenBuilding.co.uk
Not signed in (Sign In)

Categories

GBEzine

Get a whole year of cutting-edge eco-building news and project reports for just £20.00 p.a. + VAT*

1 year Green Building Ezine

Built upon 30 years of experience, this fabulous new medium will feature inspiring and in-depth articles on eco-building projects from across the spectrum and from all over the UK, most of which are written by the very people that designed or built them.

Perfect for architects, builders, developers, self builders and anyone interested in keeping right up-to-date with green building trends and friends.

Price: £20.00

Discount books are also available with your first year subscription:



*VAT will only be charged to customers with a UK address.

For institutional access
please go here



Vanilla 1.0.3 is a product of Lussumo. More Information: Documentation, Community Support.

Welcome to new Forum Visitors
Join the forum now and benefit from discussions with thousands of other green building fans and discounts on Green Building Press publications: Apply now.




  1.  
    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
  2.  
    Hi,
    Very hard to predict the future of course. Best I have heard is to install ducting on the likely routes. Then you can feed whwtever you like through it later. Renault reccomend a 7 kW home charger (fitted for free at the moment) So heavy duty wiring - not a normal ring main. Most EV's can be charged via 3 pin plug into normal socket but this takes about 10 hours to charge with current battery capacity. This is likely to double in the next few years. Also maybe put mains/distribution box in garage or near it.

    Richard
    • CommentAuthortony
    • CommentTimeJan 7th 2016
     
    I would plan for 16 A for car charging

    Re battery storage, I think charge and discharge at 240 V. Likely 13A max
    • CommentAuthorEd Davies
    • CommentTimeJan 7th 2016
     
    Posted By: Phil.Chaddah-DukeI 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?
    Yes.

    Wherever the battery thingy is it'll probably want a sensor on the main cable into/out of the house so it can know whether you're importing or exporting. So if it's going to be away from the consumer unit then provision for putting a signal cable through might be sensible. Bit of duct or something, perhaps. Of course, it might finish up as RF.
  3.  
    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
  4.  
    Hi James,
    It seems that is the way chargers are going. I could manage with a slow (3kW ish ) Charger. But a full charge will take longer than the economy 7 period if you have that. Also different tariff bands are being talked about. So a higher power charger could take advantage of low cost or even free tariffs of shortish periods in the future.

    Richard
  5.  
    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
  6.  
    Forgot to mention Tesla powerwalls etc - enough for a house may swallow space, but we may be able to use our car batteries instead / as well, so make it close enough to your secure parking spot.

    F
    • CommentAuthorbillt
    • CommentTimeJan 9th 2016
     
    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?
  7.  
    Thanks for comments guys. Billt, no direct link between car chargers and storage, just two open questions regarding wiring (: Apart from cost, is there any downside to oversizing cable for car, say put a chunky 100A cable to handle whatever is required. Actually I have a coil of armed cable that we used to divert the mains supply of the house during our excavations, been looking to reuse it?
  8.  
    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
    •  
      CommentAuthordjh
    • CommentTimeJan 9th 2016
     
    Posted By: billtTaking 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.

    That's what some of the free chargers were about. Getting a group of them in use in a small area to see what happens in real life. Seemed like a good idea to research it to me, though I don't know what's been learned.

    It seems to me that it's at least as likely that we'll eventually switch to a renewably-generated liquid fuel like methanol for transport use given the combination of storage, distribution and in-vehicle requirements. It seems easier to produce a balanced system than either electricity or gaseous fuels.
Add your comments

    Username Password
  • Format comments as
 
   
The Ecobuilding Buzz
Site Map    |   Home    |   View Cart    |   Pressroom   |   Business   |   Links   
Logout    

© Green Building Press