EV Rooftop Solar Charger by GoSun

[moosetags]

I think that this is a really good idea in right direction, but it is not quite there yet. I do believe that viable options like this are on the horizon.

Brian

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[ThumprMN]

I would buy it just to roll out when a hail storm is coming.

Captain, DEPLOY THE SHIELDS!!!

 

[Olsonsolar]

Cool idea but mostly a gimmick.

Rough break even point:

1200W of solar will produce ~800W max in peak sun.

0.8kWh per hour of use. Assuming $0.20/kWh ~$0.16/hour of full sun

3000/0.16 = 18750 hours of full sun needed to break even

Honestly my guess is the panels break down and are ineffective before you recoup your cost.

1200W of solar will produce ~800W max in peak sun. Not quite sure how you figure that????

It could produce much more than 800W, it would depend on the sun angle but you're right it probably would hardly ever get the full 1200W.
How ever it does look like a cool idea. But stretching it our over the hood would eventually scratch the heck out of it. Then there is the wind factor.

 

[jjswan33]

1200W of solar will produce ~800W max in peak sun. Not quite sure how you figure that????

Just based on physical understanding and personal experience.

1. I have 300W of similar thin solar panels (quality built) on the roof of my camper. They have never produced more than 220-230W even with the sun perfectly overhead
2. These will never all be simultaneously all perfectly oriented to the sun just by design

 

[Mathme]

At .8 kWh/hour, you'll only get 8-10 kWh of charging (best case) in an entire day of full sunlight. That's 16-20 miles of range (best case) per day. As others have said, that's a whole lotta (best case) days to recoup your investment.

Solar panel technology just isnt' efficient enough these days to charge the batteries in these vehicles. I have 23 400w solar panels on the roof of my house and on a completely sunny summer day they will produce about 50 kWh energy per day. In the winter, that same array only produces about 20-23 kWh per day.

 

[SR71]

Range extension vs drag loss was my first thought.

 

[Deacon]

Could be good in areas where power goes out due to hurricanes, etc. - however, not really enough juice.

 

[DaveA]

Cool idea but mostly a gimmick.

Rough break even point:

1200W of solar will produce ~800W max in peak sun.

0.8kWh per hour of use. Assuming $0.20/kWh ~$0.16/hour of full sun

3000/0.16 = 18750 hours of full sun needed to break even

Honestly my guess is the panels break down and are ineffective before you recoup your cost.

I couldn’t care less about getting my money back in solar energy, but rather having the option to recharge 15-20 miles a day when off in the boonies or in off grid areas is nice peace of mind.

 

[CharonPDX]

If you live in a truly remote area, or do a lot of real off-the-grid over landing with long stops at each location, this MIGHT make sense. But it’s a heck of an expensive option.
Where I am, in winter this would be lucky to add one mile of range per day.

 

[VSG]

I couldn’t care less about getting my money back in solar energy, but rather having the option to recharge 15-20 miles a day when off in the boonies or in off grid areas is nice peace of mind.

Yeah but that's the thing - you will NOT get "15-20 miles a day" on a Rivian.
You just won't. It's not a reasonable estimate. If you buy this product based on their marketing, then you only have yourself to blame.

Anyone who has solar on their house should be able to tell you how many kWh to expect per day from a 1200W panel with optimized placement. The panels on this product are not going to be as efficient, and the panels, draped over the car like that, are nowhere *near* optimal placement. If the front end is facing the sun, the back end will be in the shade, and vice versa. You're not going to get close to the same total energy as a rooftop panel oriented and slanted to capture as much light as possible as the sun moves across the sky over the course of a day or year.

My experience with solar tells me you'd be lucky to get 5 miles per day on average from that system. As long as you park in the full sun and don't use your vehicle all day. Which MIGHT be enough to cover your vampire drain. So not useless, but not really useful for any of these "stuck in the woods and only need a few miles to get home" scenarios either.

People keep throwing around "peak" values as if that's what you're going to get all the time throughout the day and even in winter. 1200W x 12 hours of daylight = almost 15kWh right? That's just not the case. Even at high noon on a clear summer day those panels are not going to be perpendicular to the Sun, and aren't going to produce that full 1200W. And then an hour later, you will be getting even less because the Sun has gone down in the sky a bit and the angle has changed and the light is passing through more atmosphere with more loss. And 4 hours later you will be down to just a fraction of what you were getting at noon. The maximum you do get will be much less, and for far shorter than most people take into account.

 

[VSG]

At .8 kWh/hour, you'll only get 8-10 kWh of charging (best case) in an entire day of full sunlight. That's 16-20 miles of range (best case) per day. As others have said, that's a whole lotta (best case) days to recoup your investment.

Solar panel technology just isnt' efficient enough these days to charge the batteries in these vehicles. I have 23 400w solar panels on the roof of my house and on a completely sunny summer day they will produce about 50 kWh energy per day. In the winter, that same array only produces about 20-23 kWh per day.

Okay, you say your 9 kW of rooftop solar gives you an average of (50 + 20) / 2 = 35 kWh a day over the year. That's about 4x the size of your system every day (4 x 9 = 36). That's pretty reasonable and typical in my experience.

Apply the same logic to the 1.2 kW panel. 4 x 1.2 =< 5 kWh a day, assuming the entire panel is pointed at the sun like a rooftop panel would be. But we know the panels draped over the car will NOT be as well oriented as a rooftop panel. Regardless, 5 kWh (at most) translates to 10 miles (at most) for a Rivian (Level 1 charging gives you 2 miles per kWh, after losses). Use @jjswan33's derating of 2/3 and that's really closer to 6 miles a day (at most). But the orientation of those panels is going to kill your yield, which is why I said (in #25) that you'd be lucky to get 5 miles a day on average.

My point is, using real-world rooftop solar numbers you should be able to come up with a realistic expectation. And it is unrealistic to expect more than about 5 miles a day from this system when powering a Rivian. If that's worth $3000 to you, then go for it. But I think there are going to be some very disappointed and angry people out there who bought it expecting 30 miles a day like their advertisement says, but that's clearly an unreasonable expectation.

 

[Chewy734]

I’d prefer something like this on the top of my Rivian:

 

[Zoidz]

Here's a graph of typical output during the day from a 1 kw panel that has been properly oriented in full sun. Hopefully we can agree that panels draped across the vehicle are not properly oriented and will have a lower output? In this graph, a 1 kw panel is peaking at 600 watts for a few hours. If you want to do this type of set up, great. Just understand that the limitations are significant due to the less than optimum orientation of the panels and the manufacturer is not really telling you the stark reality. Ask yourself why the manufacturer has not provided actual test data or graphs.

In the graph below, realistic daily output of a fixed, properly oriented south facing panel is 1566/365 = 4.2 kw per day for a 1 kw panel. Clearly this portable system will not achieve this amount of output due to the panel orientation challenges.

You can run your own simulation for your area at https://pvwatts.nrel.gov/

 

[CharonPDX]

Anyone who has solar on their house should be able to tell you how many kWh to expect per day from a 1200W panel with optimized placement. The panels on this product are not going to be as efficient, and the panels, draped over the car like that, are nowhere *near* optimal placement.

My rooftop solar has a “nameplate capacity” of 7.54 kW. Made up of 26 290W panels.
My house isn’t perfect North-South. So most of my panels are on a West-Southwest angle with eight on South-Southeast. (155 degrees and 245 degrees,) with a roof angle of 22 degrees.
I’m a touch north of 45 degrees North, so sunrise to sunset on the summer solstice is 15 hours 40 minutes. Clear view of the South sky, other than a few trees that start to block about half an hour before sunset

A perfectly sunny summer solstice, my best panels generate precisely 2.00 kWh. The “worst” panels produce 1.90 kWh.

so, assuming these 1200W total panels are perfectly placed, not just draped over the top of a car in an arc, could expect ~8 kWh on a perfectly sunny summer solstice at my latitude.

On a Rivian, that’s ~15-20 miles of range.

On an equinox, with real weather, at the position they advertise? Those same 1200W of panels would produce 1/3 that.

Cloudy winter day? You’d be lucky to add 1 mile of range.

I’ve had my whole rooftop solar array produce as little as 2 kWh total over a day in November through January. And that’s not even counting days it got covered in snow and produced less than 0.5kWh.

 

[SwampNut]

At first glace I thought "silly"

You were right the first time. This is incredibly dumb. I would laugh (sadly) if the drag of having it installed eats more miles than it can give...

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