How Long Till Solar Powered Car?

[Saghost]

That's a better idea, but still not enough insolation on roof that size to make it decent. You might be able to stretch and put 600 watts of solar on that roof if you are lucky, so figure most of the time it's not parked optimally, maybe even partially shaded. A couple of kWh if you are lucky and doing it right. How far can that take you? Even a small electric bicycle needs 250w. I'm going to assume an AWD mule-tpye vehicle needs a 10kW motor, and will probably pull a few kW driving on average. So you might get an hour of operation each day if you are lucky. (I'm being optimistic)

Still better off installing panels on the house (or village) and plugging the vehicle in. They can be tilted optimally and not shaded.

If optimal utilization of solar panels is the overriding priority, you're undoubtedly right. However, in this case I respectfully suggest that this is a lower priority.

The solar panels are a rather light, fairly inexpensive piece of this car (which itself is supposed to be inexpensive.) Not having them installed won't make the car significantly cheaper, easier to build, or more efficient. Having them does give it a lot more utility and flexibility, especially if the village doesn't have panels of their own, as most don't in the 3rd world.

(In the areas of Africa and India and China I had in mind, shading isn't likely to be an issue - I suppose it applies in the more forested parts of the third world. The Rain Forest is really a poor fit for this car.)

To my mind, it seems like there's a lot more value in having the cars mass produced in a factory and sent to those places able to drive themselves around instead of sending nearly as expensive cars and solar panel kits to villages and trying to find enough skilled people to install and maintain them and worrying about wiring and exposed connections and plugging things in.

600W as a little generous agrees well with my initial approximation - the typical golf cart appears to be just under 4' x 8', and my rough numbers were showing just over 500W on a flat roof in that size range. Based on that, I was thinking a ~5 kWh usable battery pack - able to absorb about two days worth of power (with a small universal charger as well, of course, for those places you can charge it.) Keep everything at 48V (or less?) so there's little risk of injury, use sealed hub motors on all four wheels and include a fifth sealed motor as a dedicated PTO for all the utility tasks at either front or rear.

The hour of use on a typical day's solar energy is undoubtedly reasonable too - if that hour is spent driving ~25 mph down a good road. Crawling at 6 mph along the difficult trails that I assume are more typical in those parts or pumping water or charging OLPC computers/cell phones it'd last a good bit longer, and having the solar panels and battery bank as a mobile resource would let it be used in more places around the village for more different things.
Walter

 

[malcolm]

I think we should cover all man-made structures in PV before covering nature

Which was covered in the first link.

"....in large arrays on the ground or on rooftops or even floating on lakes. "

Here's the section:

The FTCC system overcomes the limitations discussed above. In particular:

• Water veil keeps the PV panel at low temperatures with an average yearly energy gain of more than 10 percent.
• The floating platform allows a very efficient one axis tracking, so that reflectors can be easily oriented to increase radiation collected on the panels.
• The system exploits the unused areas of artificial reservoirs and has a very limited environmental impact.

 

[Bishop]

oddly enough before they went out of business the Fisker Karma had solar panels built into the roof that would provide a trickle charge (granted not very fast but it was better than nothing) Im actually surprised nobody else did it it wouldn't fully charge your car but it would give you a little bit more than just sitting

 

[deonb]

oddly enough before they went out of business the Fisker Karma had solar panels built into the roof that would provide a trickle charge (granted not very fast but it was better than nothing) Im actually surprised nobody else did it it wouldn't fully charge your car but it would give you a little bit more than just sitting

The "little bit" while sitting was really only a mile per day - in perfect sun. Well, was supposed to be, but it didn't even do that. It just charged the 12V accessory battery.

To put that in perspective, you need 3 times the amount of panels on the Fisker just to overcome the vampire drain of the Model S.

 

[Ingineer]

Yes, Nissan added a Solar Panel to the Leaf for trickle charging the 12v battery. It didn't even overcome it's Vampire drain, just slowed it down such that your car could sit for a month instead of only 2 weeks without a dead battery.

 

[tander]

oddly enough before they went out of business the Fisker Karma had solar panels built into the roof that would provide a trickle charge (granted not very fast but it was better than nothing) Im actually surprised nobody else did it it wouldn't fully charge your car but it would give you a little bit more than just sitting

Somebody up the thread mentioned an old Audi with that idea that could keep the AC on in the summer while the car wasn't running, seemed like a great idea for dogs if nothing else.

 

[JRP3]

Yes, Nissan added a Solar Panel to the Leaf for trickle charging the 12v battery. It didn't even overcome it's Vampire drain, just slowed it down such that your car could sit for a month instead of only 2 weeks without a dead battery.

Exactly why I would want a larger sized panel on a car. Anti vampire and maybe a few free miles.

 

[Ingineer]

Somebody up the thread mentioned an old Audi with that idea that could keep the AC on in the summer while the car wasn't running, seemed like a great idea for dogs if nothing else.

The A/C can easily pull several kW even on a cooler day. There's not enough space on the car for that kind of load. Even if you are plugged into a 120V outlet, that's not enough to cover the whole load of the A/C!

You could run the fan though to ventilate the cabin a little.

 

[tander]

The A/C can easily pull several kW even on a cooler day. There's not enough space on the car for that kind of load. Even if you are plugged into a 120V outlet, that's not enough to cover the whole load of the A/C!

You could run the fan though to ventilate the cabin a little.

Yeah I don't know the specifics maybe that's how it worked.

 

[JRP3]

Even if it doesn't make "sense" people seem to want it

The first most common response is "Does it have solar panels on the roof?"

Short-Term TSLA Price Movements - 2016

 

[jgs]

The A/C can easily pull several kW even on a cooler day. There's not enough space on the car for that kind of load. Even if you are plugged into a 120V outlet, that's not enough to cover the whole load of the A/C!

You could run the fan though to ventilate the cabin a little.

That's exactly what it did. That was the A6 ca. 2000, as I recall. Only sold in hot climates.

 

[tander]

Just thinking about an electric truck or suv and I think it's going to make a lot of sense, a lot sooner that most seem to think to have a solar canopy or something. There are plenty of people who want to be able to drive out to some remote camp spot or backpacking where they might just leave there car for days at a time, in which case it could make plenty of sense to have a solar canopy or awning or something. I could see people driving down some remote road and trying to see how far they could get and then camping till they had enough juice to get home.

 

[deonb]

I could see people driving down some remote road and trying to see how far they could get and then camping till they had enough juice to get home.

Sounds like a great idea to generate dozens of sales!

 

[Saghost]

Just thinking about an electric truck or suv and I think it's going to make a lot of sense, a lot sooner that most seem to think to have a solar canopy or something. There are plenty of people who want to be able to drive out to some remote camp spot or backpacking where they might just leave there car for days at a time, in which case it could make plenty of sense to have a solar canopy or awning or something. I could see people driving down some remote road and trying to see how far they could get and then camping till they had enough juice to get home.

The two obvious answers to this scenario are a travel trailer with solar panels on the roof or a stack of the semi flexible modules in the cargo area.

Without the aluminum frames and glass top, the flexible panels are maybe a quarter inch thick (more at the contacts, I think) and only a few pounds each. Hang them over the truck or set them up at the camp site, then hook them in through charge controllers and a inverter.

(I'd probably go the travel trailer route, but that does limit your trail options somewhat.)

 

[tander]

The two obvious answers to this scenario are a travel trailer with solar panels on the roof or a stack of the semi flexible modules in the cargo area.

Without the aluminum frames and glass top, the flexible panels are maybe a quarter inch thick (more at the contacts, I think) and only a few pounds each. Hang them over the truck or set them up at the camp site, then hook them in through charge controllers and a inverter.

(I'd probably go the travel trailer route, but that does limit your trail options somewhat.)

Not exactly sure what they have going on with their trailer but this is along those lines: Canadian couple to drive across Canada in a Tesla Model X with solar trailer

 

[HEIDELCEDRIC]

So a while ago Toyota had a Prius where you could get a solar roof panel. How long until someone has meaningful solar charging with panels or photo-voltaic paint or something (guessing it will be a decade or more before it could be relied on a sole charging source)?

This question was asked at the 2016 Annual Stockholders meeting a few weeks back, and Elon respectfully said Tesla will never ever make a car with Solar Panels as it is both incredibly expensive and the solar panels would not actually produce enough power to do anything useful.

 

[tander]

This question was asked at the 2016 Annual Stockholders meeting a few weeks back, and Elon respectfully said Tesla will never ever make a car with Solar Panels as it is both incredibly expensive and the solar panels would not actually produce enough power to do anything useful.

No kidding? I wouldn't be surprised if he said not for a long time or something like that but surprised he said never.

 

[HEIDELCEDRIC]

No kidding? I wouldn't be surprised if he said not for a long time or something like that but surprised he said never.

He explained that putting solar panels on a car is not actually as appealing as people think, due to the fact that it adds a lot of weight to the car and it generates almost no electricity. Instead they said that they are working on making charging at home and at "destinations" more easy and appealing.

 

[JRP3]

due to the fact that it adds a lot of weight to the car

That seems like an odd statement, as in not true. For example 300 watt LG panels weigh 37 lbs LG LG300N1C Black Mono 300 watt Solar Panel - Wholesale Solar And that's probably with little to no concern for weight optimization.

 

[Saghost]

That seems like an odd statement, as in not true. For example 300 watt LG panels weigh 37 lbs LG LG300N1C Black Mono 300 watt Solar Panel - Wholesale Solar And that's probably with little to no concern for weight optimization.

I'd think car installations would be closer to the flexible panels used for boats and RVs than the hardened rigid stand alone panels used in house installations - in which case it's more like 3 pounds for 100W:

Solar Flex Kits | Go Power!

So yeah, covering the roof and hood isn't going to add significant weight. It does add substantial expense and interfere with sunroofs and the like (unless you get the fancy expensive translucent panels they use in some shopping malls?) - and it won't add any significant fraction of the range a typical driver uses on a daily basis, so I'm not convinced it makes much sense, but I agree the weight isn't a big driver.
Walter