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Hi,
This question seems more appropriate for the Energy part of the forum…
I’m currently in the research stage as a potential Zoe owner, so not taken the plunge yet, and also at the same time I’ve been looking in to solar PV too.
The case for having solar installed seems to be a no-brainer in terms of return on the investment, regardless of whether I buy a Zoe or not. In my situation there will be plenty of days when the Zoe will be at home during the daytime, so can be recharged when solar is generating – which I consider a pleasant bonus towards the case for having solar installed. I’m certainly not kidding myself that the solar will payback much in Zoe recharging since the electricity cost isn’t that much to save anyhow, but nevertheless it’s a nice perk towards the case for both EV and solar, and there’s something very elegant and ‘right’ about the energy going directly from solar to a car battery.
However, looking at other posts and information about combining a Zoe with solar PV, it seems apparent that a domestic solar installation of 3 to 4 kW clearly won’t generate enough power to feed a domestic 7kW Zoe charging point, so the best case scenario is half the power from solar, half coming from the grid (which could still be on a green supplier tariff, of course).
Now one idea comes to mind, but I’m not sure if it’s a good idea or not… Would it be feasible to charge off a granny cable in order to intentionally extend the time it takes to charge a car that’s at home for full daylight hours. I.e. charge at 10amps (2.4kW) for several hours in daylight, rather than using the 7kW socket, with the intention of drawing all the power from solar but slowly rather than half-and-half solar/grid?
Or is the granny cable not a good idea as a regular arrangement (just for occasional use)?
Alternatively, is there a way to connect on the 7kW socket but tell Zoe to “drink slowly”?
Thanks!
I think you’ve got the right idea. I have a big solar array and use it at weekends to charge the ZOE, but can’t avoid some of the power coming from the grid since ZOE takes so much. I’m thinking of getting a granny cable for just that reason (though I accept that it charges very inefficiently so a fair proportion of the power will be lost).
If you don’t yet have a charge point and are very keen on solar charging then perhaps it’s worth considering getting a 3kW rather than 7kW one? A decent sized solar array should give you 3kW during the summer. Or maybe you could buy a charge point that has the option of different power ratings (I haven’t researched whether such things exist)?
These kinds of questions will become increasingly important as more people go solar. I have heard the latest BMW charge point has an option to charge only from solar, but I believe it’s pretty expensive (and presumably needs extra, dedicated wiring).
Do you know just how inefficient the granny cable is?
I hadn’t thought about getting a 16amp wall unit rather than 30amp. I see there’s the different options on the British Gas site…
https://www.britishgas.co.uk/energy-saving-products/electric-vehicles/electric-charging-offersDid you get the choice when it was ordered through Renault, or do they assume you’ll always have 30amp if you’ve ordered a Zoe?
Is there an option to have more than one unit installed? E.g. 16amp in the garage, 30amp on the driveway? I suspect probably not given they’re government subsidised!
Also, just out of curiosity, what do British Gas mean by tethered vs non-tethered?
I’m guessing my question about whether you can somehow select on the Zoe to “drink slow” from a 7kW point is a “no” otherwise you would have suggested that. Shame really, since it must be just software somewhere in the car that negotiates the current.
Cheers
Could you go into detail re the inefficient granny cable?, and with the BCI charging with the Zoe would there be any guarantee that she would take a charge from a DIY set up if a 20 K sterling CP won’t work at all sometimes?
tethered vs non-tethered
unit where u use your own charging cable or a unit where the cable is pre fitted
i would recommend u get the tethered version… so much more easier otherwise everyday you will have to get the cable out of your boot…
also officially you are not allowed to have 2 charge points at one property address. OLEV will only pay for one. of course you can pay the full wack for the 2nd unit…
There have been lots of mentions of granny cable charging being inefficient on a Zoe. This seems to stem from the long predicted charge times, which are very pessimistic.
I use a home-made 10A granny cable most weekends while visiting the MiL. In the 5 hours we are normally there, it charges from ~50% to ~90% – so about 8% per hour. At the start of the charge it predicts 9+ hours for a full charge, but if allowed to reach 100%, it takes less than 7 hours.
Home made granny cable??? Sounds dangerous!
Do you insist that you mother in law is the one who plugs it in? 😉
It’s perfectly safe; just not as pretty as commercial versions:
A bit more on the BMW solar charging system:
http://insideevs.com/bmw-unveils-home-charging-services/Hi
My 4 kW (3.6 kW in reality)solar is tied to the grid, so when the sun isn’t shinning Zoe will charge from the grid. Assuming it is possible to have a system (usually called a diverter) that will only connect to the granny cable when there is sufficient solar output to feed it, how would the Zoe charger cope with an intermittent supply?My guess is it wouldn’t, but does anybody know?
Even without anything clever the voltage will be lower when the supply is from the grid and will rise when the solar kicks in, so Zoe will see a varying supply voltage depending on the radiance level falling on the solar panels.
Fred
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