Solar and electric vehicles

GreenBo

I'm wondering if the payback on Solar comes down if you use some of the electricity they produce to charge up an electric vehicle. Has anyone done the maths on this that they could share please?

tunnel

GreenBo wrote: »

I'm wondering if the payback on Solar comes down if you use some of the electricity they produce to charge up an electric vehicle. Has anyone done the maths on this that they could share please?

I'm sure it could come down if you were to use a diversion switch(like immersun or iboost) to transfer any spare leccy to charge a car. Depends really on how much you use the car as to how many charges you'd need.

pinnks

not sure how iboost works or chargers for that matter but immersun can only proportionately switch resistive loads. There is a threshold switch but that just turns the device on when an export threshold is reached and then for a set time.

tunnel

It was only meant as an example, there's also the wattson solar plus with optiplug which will only allow the plug to work when there's enough export. Obviously that would also depend on the type of car charger used. I know some pv'ers who've had the free wall chargers installed, the above mentioned would only be of use via a 13 amp fused plug charger.

pinnks

That's true and I think the Smappee can also do something similar, though I don't have one so could be mistaken.

zeupater

GreenBo wrote: »

I'm wondering if the payback on Solar comes down if you use some of the electricity they produce to charge up an electric vehicle. Has anyone done the maths on this that they could share please?

Hi

No, if your system is registered for FiT payment there would normally be a payback on standard household usage, however, the payback period can be reduced if you consider ways to increase the percentage of generation which you consume yourself.

As others have mentioned, the most popular way of doing this without increasing the risk of additional energy import is to use a proportional diversion device, usually to provide DHW.

As for EVs, tunnel is correct. With an EV many have fast-charge points installed, however, when combined with solar pv the increased current requirement would logically result in a larger proportion of energy import than would be the case with the standard 13A plug option normally supplied with the vehicle ....

HTH
Z

System

I am taking delivery of an EV next month. It comes with a standard plug EVSE, and I have just had a free rapid charger installed. The rate of charge is determined by the source and the car's onboard charger. My vehicle will charge off a 13 amp socket at various rates:

Low charges the car at 5.95 amps (1300 W) and thus should work if the socket has a 6A fuse or higher

Reduced charges the car at 8.7 amps (1900 W) and thus should work if the socket has a 10A fuse

Maximum - charging at just under 12A.

I have a 2.15kWp PV solar array which, for three days last week, was pushing out a pretty constant 1800 watts. Setting the onboard charger at medium would make best use of the solar power given that kWh is the sum of output times duration.

Each KWh diverted to the car should give me about 4 miles range.

Martyn1981

Not really anything to do with PV, but here's an EV article I read today:

Study: electric cars could save UK $13bn in fuel costs by 2030

My mate's grandfather got an EV last year, because he wanted to own one before he dies. Cool!

He then decided that if you've got an EV, then PV makes even more sense, so got that too.

Hope I'm that adventurous when I get old(er). Perhaps order a DeLorean with the Mr Fussion option.

Mart.

System

I did suggest that an I8 with its big gulls-wing doors would give us (both senior citizens) better access. Sadly, for me, my better half put her foot down rather firmly and my plans changed. Of interest, a bit like PV solar, the grants are beginning to fall. OLEV has just reduced the home charger grant from £900 to £700. No doubt a reduction in the car grant isn't far off.

khris210

If you charge an EV or run a washing machine etc when it's dark, you are using grid juice at 11p per unit(eg) If you do it when it's light you reduce your grid consumption by the amount your panels are producing and are therefore saving money. Remember you get paid for the electricity your panels produce whether you use it or not, therefore it's obvious that you should run appliances during daylight hours where possible, but not at same time. So for example, your panels produce 2kw and your washing machine uses 2kw, when it stops you charge your EV at 2kw. Result, no grid juice used. But if you ran both together, it would cost 2kw per hour. (enter your own figures) Obviously it's not always possible to do this, but over a year it will make an appreciable difference. Allowing for the fact that we use TVs and lights at night, we do everything possible during the day, but one at a time. Most years we produce 2700kws equalling £1035 FIT (average round figs) and reduce our grid usage by about half. We charge the EV (Nissan Leaf - brilliant) mostly on the timer from 7.30 am to 4.30 pm. Summer will extend the early morning hours when we are not otherwise using power, so it will be fully charged by 8 am. Result! The figures are interesting but don't get uptight about them.

khris210

Further to my reply above, it's not sensible to charge an EV from a house 3pin plug, unless your wiring is in tiptop shape, and even then it's dodgy due to the high currents drawn. If you have a dedicated socket in your garage with its own mains supply it's ok, but the free wall chargers now supplied are a much better bet. Although their really not fast, 4-5 hours from empty. Mine is 16amp.