Speak EV - Electric Car Forums banner

1 - 20 of 51 Posts

·
Registered
Joined
·
377 Posts
Discussion Starter #1
Im interested to know if any of you are using just solar to charge your leaf if so how many panels ect would i need.
Im not to fussed with putting it back into the grid more interested in just having the panels and being able to plug in day time and charge my car.
 

·
Registered
Joined
·
754 Posts
Im interested to know if any of you are using just solar to charge your leaf if so how many panels ect would i need.
Im not to fussed with putting it back into the grid more interested in just having the panels and being able to plug in day time and charge my car.
My system has 12no 250w panels (approx 19 m2) providing a 3 kwP system or about 2500 kWh a year which at about 4 miles per kWh theoretically provides 10,000 per annum miles solar powered. In practice we charge car overnight so in a sense we bank some of our power with the grid. Obviously a LEAF from a home charging point charges at about 3.3 or 6.6 kW so for my system needs additional grid power even at 3 kwP which is quite rare. On a sunny day we may average say 2.4 kW for a few hours so that equates to using the brick ( 3 pin plug) at 10 amps. If you went up 4 kwP (16 panels) you might be able to use the 16 amp version of the domestic charger for reasonable periods which is what you seem to be after. If you go above 4 kwP some complications arise and payback periods decline but if you got say a 9 kwP system you would probably get 3.3 to 6.6 kW for long periods when you could charge LEAF without grid input.
The best payback period I got quoted was for 3 kwP at just under 6 years and my system has been running over last 2.5 years at least 10% better than forecast ( 2200kwh/pa).
 

·
Premium Member
Joined
·
1,579 Posts
It's virtually impossible for even a 4 kW(p) array to charge an EV without drawing some current from the grid. That's because over a four hour period, the sun's intensity changes, due to clouds and the curved path it follows which alters the angle the light hits the panels.

I've posted the output from Sunday 3 August, which was a fairly sunny day, with peak output of 3.3 kW at around 3pm
upload_2014-8-29_16-6-23.png
 

·
Registered
Joined
·
2,155 Posts
It's virtually impossible for even a 4 kW(p) array to charge an EV without drawing some current from the grid. That's because over a four hour period, the sun's intensity changes, due to clouds and the curved path it follows which alters the angle the light hits the panels.

I've posted the output from Sunday 3 August, which was a fairly sunny day, with peak output of 3.3 kW at around 3pm View attachment 1710
Excellent graph.
I think (and I've said it before!) it's a fool's errand trying to rely on solar to charge your car.
We regard any solar that we use as a bonus, and try to run things (washing machine etc) during the day to get the best out of it, but as these things need to run anyway it just makes sense to use solar when possible.

By all means, if you can, charge the car at home during the day, and time it for average peak solar output but to try to do anything to slow down your charge to match what you're getting from the sun is just madness, it's too variable.
 

·
Registered
Joined
·
8,106 Posts
We never try. We let all our surplus solar go out to the grid to help reduce the use of "dirty" power in the day and then we charge overnight, on 100% renewable power, at low peak and low rate on our E7.

However, once we have home storage solutions for solar we could charge up the home battery using solar and charge from it when needed.
 

·
Registered
Joined
·
754 Posts
It's virtually impossible for even a 4 kW(p) array to charge an EV without drawing some current from the grid. That's because over a four hour period, the sun's intensity changes, due to clouds and the curved path it follows which alters the angle the light hits the panels.

I've posted the output from Sunday 3 August, which was a fairly sunny day, with peak output of 3.3 kW at around 3pm View attachment 1710
Whilst agreeing its a fools errand to rely on solar charging of your car with a 4 kwP system - I'm not sure I agree with it being virtually impossible to charge an EV without drawing fro the grid. If you use the brick to limit the draw to 2.4 kW I think there will be some mid-day hours of possibility but it would be more trouble than its worth and involve deactivating most of your house's electrical appliances. You can see however why people keep chasing this Holy Grail though.
There is another possibility of storing the excess going to the grid and then use that later to top up the LEAF. I floated sometime ago on the other forum the idea that Nissan look into a supplementary "winter" battery pack of say 12 kWh which in sunny summer resides in your garage/ outhouse and is configured to charge only from the PV generated excess normally going to the grid. The LEAF could possibly top up from that at night and also possibly other devices.
The LEAF range drops off in winter and would particularly benefit from an add-on 12 kWh pack and there has been discussion about potential spare volume in its boot capable of accommodating extra battery modules. Is this possible/ affordable/ viable - who knows but presumably Nissan read these threads and could look to incorporate something into their next generation LEAF if not practical with the current. We've all got 25 years of PV to do something with and there are already systems on the market trying to use this excess.
 

·
Registered
Joined
·
8,106 Posts
There are no add-on packs available yet but it may be possible. Having said that, I wouldn't play around with my Leaf battery system until it was out of warranty and that isn't for another 2 years at best for anyone in the UK. I am sure it will happen as there are a lot of clever people interested in doing making it happen.

There are devices you can buy to divert surplus solar power but they only work with resistive loads like immersions. It wouldn't work with a switchable load or an EV AFAIK as the available power would vary constantly. When there is a device to allow us to charge from surplus electricity from solar I will be one of the first in the queue :)
 

·
Premium Member
Joined
·
1,579 Posts
There are devices available using battery storage for demand peak smoothing – search for 'NEDAP power router' and 'Moixa Maslow'. The principal barrier is the high cost.
 

·
Registered
Joined
·
754 Posts

·
Registered
Joined
·
8,106 Posts
All form and little function... look at those skinny solar panels... about as much use as a chocolate teapot... or even the solar panel on the spoiler of the Leaf!

:)

Looks great tho!!!
 

·
Registered
Joined
·
12 Posts
We have a 4KW solar system on our roof ( rent a roof scheme )

when the panels are putting electricity into the grid, our digital electric meter has a red light showing and the meter is stopped,, no figures showing,

We have a LEAF Acenta on loan until our new Tekna arrives from Sunderland,

we only got this loan car Tuesday ( our first EV ) and yesterday thought we would try the British Gas Fitted Type 1 Polar charger,

plugged the LEAF into charger, there was 2 static lights and one flashing light on the dashboard,

the red light on our electric meter stayed on, ( meter stopped ) so the panels was chargeing the lEAF and costing us nothing, plus one fridge and one freezer working,
 

·
Registered
Joined
·
1,150 Posts
This is the exact problem I aim to solve with my smart solar charger. Step up the charge rate when the sun shines and step down or stop when the clouds come over. ideally you'll specify you need x% charge by certain time and the system will take what it can fron solar and go to the grid at the latest moment to top
 

·
Registered
Joined
·
8,106 Posts
@FenTiger That is great! 100% solar charging.

What was the state of charge when you plugged in? 2 steady lights and one flashing could mean that the car is near full and so it might not have been drawing the full power.

Do you have 32A charging on the car?

The problem many people don't realise is that a 4kWp system such as yours will only generate enough to charge a Leaf with 3kW charging occasionally... when the sun is full out. Most of the time you will be buying electricity from the grid. If you charge at 7kW then you will never be able to charge 100% using solar unless you use a charging station that has adjustable rates such as a DIY-built one.
 

·
Registered
Joined
·
2,026 Posts
Yes always charge from Solar, got a 4kw system, car is at home all day, nice feeling to drive on sunshine, got the phoenixworks to do mine,super job, used micro inverters, very efficient system and has paid me nicely in the first year as well as run my car and my house.

Here is my system

 

·
Registered
Joined
·
8,106 Posts
Good vid @knoxie. Thx. :)

When we move I shall consider micro-inverters again for our new system especially as it might be a dual aspect roof so I might need a dual-string inverter or 2 inverters... micros would resolve that issue easily.
 

·
Registered
Joined
·
754 Posts
Yes always charge from Solar, got a 4kw system, car is at home all day, nice feeling to drive on sunshine, got the phoenixworks to do mine,super job, used micro inverters, very efficient system and has paid me nicely in the first year as well as run my car and my house.

Here is my system

Good work Knoxie might give Phoenix a chance to quote on golf clubhouse under consideration as they look to be within striking distance and we could do with remote monitoring by mobile.
 

·
Registered
Joined
·
2,026 Posts
Hi Paul, Casper yes Micro inverters offer many advantages over a string inverter esp if you have shading issues or a tv antenna where birds poop on one of your panels :mad: ha ha you of course pay more for micro inverters but you get that back in the long run, I was very happy with the service I had from the Phoenix Works and can recommend them, the enphase system is great, the remote monitoring feature is very cool too.

I would say my car year round runs from at least 70% solar, I could make this 100% by using a homebrew EVSE with a solar controller however I am happy with 70%, running your car from your panels feels great and puts to bed the argument you sometimes get from folks about long tailpipe etc, rather than go in to details I just say my solar panels power the car, next question :)
 

·
Registered
Joined
·
39 Posts
I think that the pursuit of an adapted EVSE to charge solely using solar PV energy, whilst noble, has a major potential pitfall. I believe that with typical home PV installations ranging from 1.5 to 4kWp, there will be many occasions where the available PV output will cycle above and below 6A (min charging current) thus causing charging to stop and start frequently. Each time this happens the contactor cycles and on the Leaf, for instance, another charging cycle is counted. As anyone with a pv system will know, weather in the UK produces lots of large variations in output on partly cloudy days; this would result in many, many extra charging cycles being recorded by the car. The advice from Nissan is not to top the battery up from a high charge state frequently. In employing a smart EVSE it may appear that you have done exactly that in the event you have a warranty claim in the future. Also, what impact would all these extra "charges" have on the Nissan health report?
 

·
Registered
Joined
·
585 Posts
I would say my car year round runs from at least 70% solar, I could make this 100% by using a homebrew EVSE with a solar controller.
Can you back that up with hard data? Or is that just anecdotal. I find it difficult to believe you can get anywhere near 70% over the course of a year, unless you don't drive during the winter... o_O

I've have my Leaf for three months now, basically over the summer. I've modded my charger to charge at 6amps (while I build my OEM based EVSE controller, like @Dave Davies one) and tried very hard to charge during sunny days. I have also used the third input on my EmonTX (the transmitter for OEM) to watch the charger and run the stats.
I've struggled to keep it near 70% during the summer, in winter I can tell that figure is going to collapse big style.

I've already written a load of firmware for my controller, including a hardcore "only charge from 100% solar" mode. I've not tested this yet as the hardware isn't finished, but as @CW4 says, I suspect the Leaf isn't going to like it very much, with lots of clunking noises coming from under the bonnet and the L1/L2 charge counter heading into outer space. Only time and testing (and LeafSpy) will tell, but unless you're in Spain/Australia (or have a 10kWhp pannel) I doubt 100% solar charging is going to happen. Sadly. :(
 
1 - 20 of 51 Posts
Top