Using house solar panels to charge plug-in Prius

[oakridge]

We have had solar panels on the roof for four years now and they are an enormous success.  So.... I was wondering about charging the Prius batteries using this free power.  Our present GenIII isn't plug-in but it looks as though the new ones are.  I wondered what you thought.

[RobMagpie]

I do that with mine as often as I can although usually only weekends as I use the car for work. Works a treat.

[oakridge]

Thank you Rob.  Do you take power directly from the panels or just make sure you charge the batteries when it is daylight?

[kithmo]

Just to clarify oakridge, the new Gen 4 prius is not plug-in either. The new Plug Prius is called the Prius Prime, out shortly.

[johalareewi]

My cousin has solar panels on her house roof which are connected up to the main electricity supply. She also has a car charging station fitted and it charges her Nissan Leaf.  So the solar panels effectively charge the leaf with any spare electricty used in the house or fed onto the grid.

As well as looking into a plugin prius, I am looking at portable solar panels which could be used to charge the plugin while parked away from home.  A chap at work had a solar panel set up as a parcel shelf in his Mondeo which he used to charge the 12v Battery.  I have also seen thin solar panels on boats and caravans to keep the leisure Battery topped up.  With a portable charging station I could get some juice into a plugin while it is parked in the work's car park to help get me back home (I did suggest they had some car charging points but they haven't done it).

[kithmo]

1 hour ago, johalareewi said:

My cousin has solar panels on her house roof which are connected up to the main electricity supply. She also has a car charging station fitted and it charges her Nissan Leaf.  So the solar panels effectively charge the leaf with any spare electricty used in the house or fed onto the grid.

As well as looking into a plugin prius, I am looking at portable solar panels which could be used to charge the plugin while parked away from home.  A chap at work had a solar panel set up as a parcel shelf in his Mondeo which he used to charge the 12v battery.  I have also seen thin solar panels on boats and caravans to keep the leisure battery topped up.  With a portable charging station I could get some juice into a plugin while it is parked in the work's car park to help get me back home (I did suggest they had some car charging points but they haven't done it).

Just one problem with portable solar panels, they're 12v, the HV Battery is near mains voltage. As you've seen from your cousin's she probably has eight or so large panels on the roof and is probably using most, if not all, of the energy created by them to charge the car when it's plugged in, so unless you have a very big roof on your car and adequate suspension to take the weight of the panels, it ain't gonna work. If it was as easy as that all EVs would already have them on. 

[PeteB]

Even the Gen 3 Prius with the solar roof option only has solar panels that work the ventilation fan slowly when parked to reduce the internal temperature a little.

It makes no attempt to even work the A/C or charge the 12V Battery.

[RobMagpie]

My panels are connected up to the mains electric as well. Just means when it's sunny the panels charge the car rather than the mains, when it's not they make a contribution and the mains tops it up.

[Beekeeper D]

On 31 August 2016 at 11:38 AM, oakridge said:

We have had solar panels on the roof for four years now and they are an enormous success.  So.... I was wondering about charging the Prius batteries using this free power.  Our present GenIII isn't plug-in but it looks as though the new ones are.  I wondered what you thought.

An electric vehicle can pair very well with a solar electric house roof. How well is going to depend on your feed-in tariff, lifestyle and vehicle. 

 

Among electric vehicles the Prius plug-in has a distinctly limited range/battery capacity. Which provides a limit to the benefits of plugging in (particularly to your solar) - but how its electric range fits with your lifestyle is something we can't know. 

 

Since the plug-in version of the new Prius isn't yet available (anywhere in the world?), if one was to buy a new plug-in Prius tomorrow, it would be the version with a Gen3 bodyshell. 

Because the plug-in (surprisingly in my opinion) seems to depreciate faster than the regular hybrid, cross-trading to a used plug-in might cost less than you expect. 

[johalareewi]

The current plugin would work well for my commute.  For longer journeys it will be fine being a normal gen3 prius with a larger HV Battery.  While the plugin's EV range could be limiting for some, I am looking at a plugin as a gen3 prius with extra EV capability, not an EV vehicle.  If I could get some electricty into the plugin while it is sat in the sunshine at work (it happens sometimes), it will help.  Solar panel technology is improving all the time so what was impossible a few years ago is now possible.  For example, tents or gazebos which are made of solar cell material.  Just erect one over the car while it is parked.  Car sits in the shade and keeps cool.  The car cover generates electricity which tops up the Battery.

[oakridge]

This has all been really interesting and useful.  A straight electric vehicle would not be practical for us as we do quite a lot of long journeys, including to France.  I think that asking Brittany Ferries if we could the car in on our way to St. Malo would not be well received.  I think we will be reviewing the situation as Fagin said.  When I was at school in the 50s they had a couple of what they called Tilley Vans which were Battery powered with seats in the back for 6 or 8 kids but I have never been able to find anything about them.

[Mike169]

Hi, I knew a guy that had a really nice Porsche 911, sorry folks but the make of car does not matter. Cars with multiple computers constantly put a slight drain on the Battery to keep all of it's toys working. He did lots of flying round the world and found when he came back to his car that had been in the airport car park for 2 weeks that the Battery was dead flat even although it was a very good Battery. So he simply bought a solar panel, a reasonably sized one and connected it to the car and left the panel in the windscreen area (Not heavily tinted) and now he finds his battery is fine after it has been left for a significant period of time. Yes I am sorry if this is slightly off topic but I feel it contributes to solar panels dabate. Mike.

[DMGbus]

I ran a Plug In Prius for just under 4 years and have solar panels.    The trick is to wait until the sun shines before charging the car.       One option (with overnight charging) is to set the timer so that the 70 / 80 minutes of charging takes place at the right time, "right time" = when the sun is most likely to be shining [eg. 7am rather than 9pm].       The good thing about the Plug In Prius charger is that it is a slow charger so that it's power consumption can, in bright sunny conditions, be entirely provided free of charge from solar panels.     Had Toyota provided a faster charger then the rate of charge would have exceeded the output rate from a typical domestic solar installation, and thus would be partly incurring a cost.     As it happens we're talking very low charging cost figures anyway, a full charge only costing about 30 pence or less (even with no solar panels).

[johalareewi]

On 03/09/2016 at 9:02 AM, DMGbus said:

The good thing about the Plug In Prius charger is that it is a slow charger.

Indeed and it can be charged from 110V (or maybe lower).

[PeteB]

1 hour ago, johalareewi said:

Indeed and it can be charged from 110V (or maybe lower).

although I think I recall a full charges takes twice as long in the USA where the voltage is 110 (but probably better for the long term health of the battery)

[Anthony Poli]

22 hours ago, PeteB said:

although I think I recall a full charges takes twice as long in the USA where the voltage is 110 (but probably better for the long term health of the battery)

110 would be half the voltage of the full Battery, so it would have to boosted, if the cells are charged in series. Then the voltage will need to be closer to 240.

56 cells * 4.15v = 232v when charged, compared to 207v when discharged.

That is the usual method for Battery packs for example laptop batteries.

 

[johalareewi]

In the USA, they have an official MrT charging lead for the plugin to charge from their 110V domestic supply.  Takes twice as long as our 230V domestic supply.  I am not aware that the USA plugin prius has been specially adapted for the 110V domestic supply (they can still be charged from a 230V supply).  So I am assuming that any plugin prius can be charged from a 110V or 230V supply (but you might need the correct lead).

[johalareewi]

On 01/09/2016 at 0:23 PM, PeteB said:

Even the Gen 3 Prius with the solar roof option only has solar panels that work the ventilation fan slowly when parked to reduce the internal temperature a little.

It makes no attempt to even work the A/C or charge the 12V battery.

The new plugin Prius will have solar panels that charge the HV Battery :) :) :)

[Anthony Poli]

12 minutes ago, johalareewi said:

The new plugin Prius will have solar panels that charge the HV battery :) :) :)

Every little helps

Shame they never did it sooner.

[Beekeeper D]

1 hour ago, johalareewi said:

The new plugin Prius will have solar panels that charge the HV battery :) :) :)

Yes, but under best-case conditions they are only claiming it could add 3 miles/day to the EV range. 

Now we know that claimed EV miles are not as long as real miles, and that the sun here in the UK doesn't shine as long or as strongly as in say, California! There is also the matter of geometry - in their best-case situation, the sun would be overhead, shining straight onto the panels. Here the sun is low in the sky most of the time - which is why all the solar panels you see in England are tipped up at an angle of about 45°. A horizontal panel is going to lose about half its effective catchment area simply through being in the UK rather than equatorial Brazil. And even then, do you choose to park in the sun? Could you? Would you? (Its no use in a multi-story car park, unless you go all the way to the roof!)

So, in the UK, might it give as much as half a real mile of EV range per day on average? Enough to get you up to the roof of the multi-story? What is that worth, in money terms?

It'll be expensive and won't really do very much in the UK. Every little does help, but not being cost-effective suggests to me that it is unlikely to make it into the standard UK spec, and might not even make the UK options list - though doubtless the marketing men would love to see it there for image-enhancement alone.  

Sadly, it strikes me as a sort of "show car" feature. Look what we can do, rather than look at what we are actually selling. 

Whereas on the other hand, the evolution of the HSD to give nearly double the pure-electric power does sound like something that could and should be rolled out to all Toyota's hybrids.