GCC: Kia and Hyundai to introduce solar roof charging on selected vehicles: HEV, BEV and ICE

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GRA

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https://www.greencarcongress.com/2018/10/20181031-hmg.html

. . . Electricity-generating solar panels will be incorporated into the roof or the hood of vehicles, and will support internal combustion, hybrid and battery electric vehicles with additional electrical power, increasing fuel efficiency and range.

The solar charging technology is being developed to support the vehicle’s main power source, improving mileage and reducing CO2 emissions. The system will have the capability to charge the batteries of electric and hybrid vehicles, as well as those of internal combustion engine (ICE) vehicles, helping to improve fuel efficiency.

Hyundai Motor Group is developing three types of solar roof charging systems: . . . .

The first-generation system, which will be applied to hybrid models, is created out of a structure of silicon solar panels that are integrated into a standard car roof. This system is capable of charging 30 to 60 percent of the battery over the course of a normal day, depending on weather conditions and other environmental factors.

The second-generation semi-transparent solar roof will be applied to ICE vehicles, representing a world-first application for the technology. The semi-transparent technologies can be integrated with a panoramic sunroof, letting light through into the cabin, whilst charging the vehicle’s battery at the same time. Applying solar charging systems to ICE vehicles will help them comply with ever more stringent global environmental laws regulating CO2 emissions.

The third-generation system is currently in testing. It is designed to be applied to the hood and roof of eco-friendly battery electric vehicle models in order to maximize energy output. . . .

Hyundai Motor Group will launch the first generation of this technology into its vehicles after 2019 to help meet global regulations targets and improve vehicle fuel efficiency.
 
theothertom said:
I wonder how much KW they will supply. IOW, is it really worth it?
If they can run much or all of the auxiliary loads, yes. Everything beyond that is a bonus - this isn't about cars that can fully charge themselves while parked.
 
GRA said:
https://www.greencarcongress.com/2018/10/20181031-hmg.html

. . . Electricity-generating solar panels will be incorporated into the roof or the hood of vehicles, and will support internal combustion, hybrid and battery electric vehicles with additional electrical power, increasing fuel efficiency and range.

The solar charging technology is being developed to support the vehicle’s main power source, improving mileage and reducing CO2 emissions. The system will have the capability to charge the batteries of electric and hybrid vehicles, as well as those of internal combustion engine (ICE) vehicles, helping to improve fuel efficiency.

Hyundai Motor Group is developing three types of solar roof charging systems: . . . .

The first-generation system, which will be applied to hybrid models, is created out of a structure of silicon solar panels that are integrated into a standard car roof. This system is capable of charging 30 to 60 percent of the battery over the course of a normal day, depending on weather conditions and other environmental factors.

The second-generation semi-transparent solar roof will be applied to ICE vehicles, representing a world-first application for the technology. The semi-transparent technologies can be integrated with a panoramic sunroof, letting light through into the cabin, whilst charging the vehicle’s battery at the same time. Applying solar charging systems to ICE vehicles will help them comply with ever more stringent global environmental laws regulating CO2 emissions.

The third-generation system is currently in testing. It is designed to be applied to the hood and roof of eco-friendly battery electric vehicle models in order to maximize energy output. . . .

Hyundai Motor Group will launch the first generation of this technology into its vehicles after 2019 to help meet global regulations targets and improve vehicle fuel efficiency.

Obviously they are talking about the 12V battery here. Since most car batteries hold less than 1kWh, that means less than 300-600Wh per day. Assuming about 4h of equivalent direct sunlight, that's 75-150W. Not a whole lot. Of course my numbers are guesses, but it gives you a ballpark idea.

I fail to see how a system that generates 0.6kWh/day or less can make a meaningful impact on fuel efficiency or range.
 
GetOffYourGas said:
GRA said:
https://www.greencarcongress.com/2018/10/20181031-hmg.html

. . . Electricity-generating solar panels will be incorporated into the roof or the hood of vehicles, and will support internal combustion, hybrid and battery electric vehicles with additional electrical power, increasing fuel efficiency and range.

The solar charging technology is being developed to support the vehicle’s main power source, improving mileage and reducing CO2 emissions. The system will have the capability to charge the batteries of electric and hybrid vehicles, as well as those of internal combustion engine (ICE) vehicles, helping to improve fuel efficiency.

Hyundai Motor Group is developing three types of solar roof charging systems: . . . .

The first-generation system, which will be applied to hybrid models, is created out of a structure of silicon solar panels that are integrated into a standard car roof. This system is capable of charging 30 to 60 percent of the battery over the course of a normal day, depending on weather conditions and other environmental factors. <snip>
Obviously they are talking about the 12V battery here. Since most car batteries hold less than 1kWh, that means less than 300-600Wh per day. Assuming about 4h of equivalent direct sunlight, that's 75-150W. Not a whole lot. Of course my numbers are guesses, but it gives you a ballpark idea.

I fail to see how a system that generates 0.6kWh/day or less can make a meaningful impact on fuel efficiency or range.
As I read it, the bolded section refers to the hybrid drive battery, and they are typically a bit over 1 kWh( IIRR the Prius was around 1.3kWh (forget which gen.), but that was total, not usable, and a hybrid battery is designed for max. power, not max. energy. Naturally, there will be a converter to run 12V loads.

As for range effects, you want to be able to run the DRLs, fan, infotainment system/computers, maybe seat/steering wheel heaters and provide some or all of the power for a heat pump (In the Prius Prime, "Toyota and Denso say the system uses 63 percent less energy than a traditional heating system, and helps extend the car's battery range up to 21 percent in cold temperatures"), plus (while the car is parked) exhausting hot air without running the battery down, thus reducing the A/C load on start-up while keeping the drive battery's full energy available for driving.

So, while a roof or hood-sized PV module will not be able to provide a lot of power, it will provide a small but sometimes significant range boost, especially when (in an HEV/ICE) you don't have to drive an alternator with a belt. This is far more useful than the token, tiny PV module on LEAF SVs. Fully covering all the car body panels (i.e. also doors/fenders) with PV would increase the aux. loads that could be handled, and would even allow intermittently-used cars (like mine) to get most or all of their charging direct from the sun, not that that's likely to be common. OTOH, any extra weight due to the modules would partially offset some of the gain.
 
GRA said:
RegGuheert said:
This type of system is a total waste on any vehicle which is parked in a garage during the daytime.
Of course, and it's also a total waste at night. So?
Let me be more clear: solar panels should not be installed on cars because in many cases they will not be usable. Many, many cars are parked in garages or other parking structures, particularly in the high-density (read: crowded) cities which you recommend that people live in. Solar panels should be installed in places where they will be hit by the sun. Otherwise we are simply damaging the planet for no reason, i.e. we are virtue signalling.

On top of that, even cars parked in the sun will largely squander the resources which went into the manufacture of the solar panels. This is because the 12V battery is likely to be full much of the time, so the panels will not produce at a full rate. Also, the panels cannot be oriented in a manner which optimizes their production.

It's a dumb idea right up there with biofuels and nearly every hydrogen-powered vehicle made.
 
It's a dumb idea, yet it just won't die. It sounds so good to those who are uninformed and unwilling/unable to run the math. Putting those same panels on a rooftop somewhere just makes so much more sense. For example, Kia/Hyundai could make much more of an actual difference by putting those panels on top of one of their factories instead on a bunch of cars.
 
RegGuheert said:
GRA said:
RegGuheert said:
This type of system is a total waste on any vehicle which is parked in a garage during the daytime.
Of course, and it's also a total waste at night. So?
Let me be more clear: solar panels should not be installed on cars because in many cases they will not be usable. Many, many cars are parked in garages or other parking structures, particularly in the high-density (read: crowded) cities which you recommend that people live in. Solar panels should be installed in places where they will be hit by the sun. Otherwise we are simply damaging the planet for no reason, i.e. we are virtue signalling.

On top of that, even cars parked in the sun will largely squander the resources which went into the manufacture of the solar panels. This is because the 12V battery is likely to be full much of the time, so the panels will not produce at a full rate. Also, the panels cannot be oriented in a manner which optimizes their production.
Or, we could let customers, who know what conditions their cars will experience, decide whether or not the option makes sense for them.

Let's look at what's likely to be a typical system, as I'm informed as well as willing/able to run the math ;) . I measured the flat roof area of my Forester this morning, and it's about 6' x 3' (the roof curves down at the front to meet the windshield, and I didn't count that area, although I could have). The Niro's about 4" shorter overall than my Forester, and I don't know what the usable width is, so let's be conservative and call the Niro's flat roof area 90% of 18 ft.^2, or 16.2 ft.^2. Converting to metric, that's 1.505m^2, call it 1.5m^2. Peak sun is defined as 1,000W/M^2 at sea level, although in many metropolitan areas actual peak insolation is more like 800W/m^2 owing to air pollution; OTOH, at altitude or in deserts it can be 1,200W/m^2 or more. As of 2015, the best research cell efficiencies were (organic, perovskite, and dye-sensitized cells) 10.6-12.6%; thin films, 13.6-23.3%; crystalline Si cells, 21.2-27.6%; and multijunction cells (with concentrators), 31.6-44.4% (NREL 2015: "Best research-cell efficiencies". They're a bit higher now: https://www.nrel.gov/pv/assets/pdfs/pv-efficiencies-07-17-2018.pdf Naturally, commercial modules are lower efficiency.

Assuming single-junction crystalline modules with an efficiency of at least 10% (12-16% is typical for commercial single-junction mono- or poly-crystalline modules) we can expect 80-120Wp/m^2, or for this panel area 120-180Wp. However, as the panels are flat rather than tilted at something close to the latitude, we have to apply a correction factor. For Northern California (Lat. say 38 deg.), NREL designated a 7/12 (30 deg.) roof pitch as 1.00, the best year-round production. For a flat installation (where the orientation is irrelevant) the multiplier is .89, so that gives us 106.8 - 160.2 Wp., call it 107-160Wp. This is enough to power most aux. loads while underway, and replace much if not all of the daily vampire drain on PEVs if parked in the sun, as well as lowering the internal temp when needed. Using more efficient modules and/or the hood area as well will increase the output.

Summarizing, while expecting a car-roof-mounted PV system to be able to recharge the drive battery significantly is not realistic*, handling most or all of the aux. loads and/or reducing or eliminating vampire drain is, if the car is regularly parked and/or driven in the sun. I live in the city, my car sits on my parking pad unshaded for 6 or more hours a day for a week or more at a time, and on road trips the sun's usually shining, I'm often at altitude, in the desert or both, and I'm often parking at trailheads with no shade. For someone whose situation is similar to mine, such a panel might make sense, depending on the price and how much it improves the mpg/range. For someone living in Dublin and/or who regularly garages their car during the day, almost certainly not.

Toyota already offers a solar roof on the Prime, but currently in their domestic market only, possibly because their current version can't meet FMVSS standards for roll-over crashes. An alternative reason is that it apparently costs the yen equivalent of $3k, which is way too expensive for what you get.


*On further reflection and calcs, let me modify that statement. If I thought it reasonable to drive a 3,000+ lb. car (instead of riding a 30 lb. bike) the 8.4 miles to work and back, it would sit in an essentially unshaded parking lot (the only possible shade would be partial and intermittent from the shadow of a few scattered light poles) for 8 hours a day. In summer, we get about 6 hours or so of peak sun equivalent. Max. driving speed enroute is limited to about 35 mph (avg. including stops for signals is under 20 mph), so I could expect at least 5 (and maybe 6) miles/kWh assuming no A/C use. Given the above facts, such a PV set-up should be able to provide all the energy I'd need to drive the 4.2 miles home for several months of the year (assuming no energy used for anything else).

Wondering how much PV on the hood as well would add, I measured my Forester's. Max. width was about 57 inches, but it tapers a bit and I figured 54" could be counted on. Avg, length after the round down to the bumper was 36", minus a square inch or two for the windshield washer nozzles. The hood slopes downwards slightly along its entire length before the round-down. Call it 13.5 ft.^2, or after converting to metric, another 1.25m^2, for a total (slightly less than flat plate) PV area of 2.75m^2. As I have a reflective, insulated windshield sunshade, when parking in the sun I normally face the car south or somewhat west of south when I have a choice, so the front of the hood and roof slopes would actually boost the useful PV gain - however, I'll assume it's all horizontal for this calc. Six hours of peak sun equivalent insolation would produce (10% efficient modules) 1.65 kWh x .89 (flat tilt modifier) = 1.4685 kWh, quite possibly allowing me to do the entire round trip commute off the car's PV. 12% or better PV and it would be pretty easy.

Of course, the ideal solution would be to cover the parking lot with a PV roof, but until the property owner does so (voluntarily or through government mandate), this would be an option.
 
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