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Solar Panel on Model S - time to reconsider?
- Thread starter Sir Guacamolaf
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Parts cost would probably be much less than that.. NRE would likely be inconsequential, since the current Model S supplier of the DC/DC already has a reference design with the boost circuit built in. If they are planning on adding a solar panel to the M3, they will likely already have spec'd this in their technical requirements. My guess would be about 4 dollars in part costs to add this circuit during the engineering requirements phase.
divesturner
Member
How about a roof rack attachable solar panel with cable to the charge port. For trickle charge during long term parking. Should be possible as third party add on. Also shades the car. Could be pretty big if removable.
Or better yet, a pop up tent garage with solar panels and a charge cable.
Or better yet, a pop up tent garage with solar panels and a charge cable.
I really like the roof rack idea for long term leaving your car at the airport situations. It'll also protect the car somewhat from bird poo.
nwdiver
Well-Known Member
That's still a really tiny niche... most people would prefer covered parking with L1 charging.... cheaper, easier and more effective. There aren't many applications where solar on a car makes sense... and in those applications it's usually a band-aid until a much better solution becomes available.
There are translucent solar panels which could make sense. Tesla is vertically integrated enough, were they could manufacture a variant of their residential solar roof product for automotive. The issue is the weight and durability.
It may be actually cheaper for Tesla to manufacture their own "solar/glass"roof rather than go to an outside supplier (for a conventional panoramic roof) since they have scale at their Buffalo, New York plant.
Plus, in locations that have high sun exposure throughout the year, any gains could be lost due to having to run the HVAC system to offset interior temperatures. Perhaps lining the cabin (i.e. headliner) with TEC's may offset the hot cabin effect.
It may be actually cheaper for Tesla to manufacture their own "solar/glass"roof rather than go to an outside supplier (for a conventional panoramic roof) since they have scale at their Buffalo, New York plant.
Plus, in locations that have high sun exposure throughout the year, any gains could be lost due to having to run the HVAC system to offset interior temperatures. Perhaps lining the cabin (i.e. headliner) with TEC's may offset the hot cabin effect.
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dark cloud
Active Member
Not a bad looking ev, with a weird name, and I love Toyota for their quality: 2023 Toyota bZ4X: What We Know So Far
But this caught my eye
This car starts at $37,000.
But this caught my eye
Range, Charging, and Battery Life
The bZ4X will come with a 64.0-kWh battery pack that Toyota claims should deliver up to 250 miles of driving range per charge in the front-wheel drive model. Going with the more powerful, dual-motor all-wheel drive variant should drop range somewhat, but Toyota has not yet released details on that model. Fast charging will be standard and Toyota says that solar panels integrated into the bZ4X will capture enough energy for about 1000 miles of driving range per year.This car starts at $37,000.
n2mb_racing
Active Member
That sounds about right, if you park entirely outside. 3 miles per day. ~700 whr per day.
But, I don't park outside, so it would be useless. It might offset the power consumption of Sentry mode, while I am parked outside at a store or something...
You compared daily drain (100W) to instantaneous production. 20% x 1000W/m2.
You have to include the effect of weather, angle and average hours of sunlight per day using PVWatts from NREL. That average multiplier is 5 for a 45 south facing roof in the mid Atlantic region. But only 4 for a untilted panel facing up.
In Seattle, it’s about 4 at 45 degrees facing south and 3.5 flat.
Using the 4 multiplier, you would only need 1/8 of a square meter of 20% efficient panel to average 100W total per day year round. That’s just a hair over 1 square foot (14” x 14”)
However, that multiplier falls to 1 in December and January …. meaning an average of 25W per day for those months and 150W per day May-Aug.
1speed
Member
There is a company out there that is offering pre-orders for Tesla solar kits... I'm not sure how far away we are from seeing this product is real life though (if ever).
www.evsolarkits.com
EV SOLAR KITS | Charge Anywhere
Solar Charging Kits for Tesla and Other EVs! Add range to your car with our portable rooftop charging kits. Clean, Mobile, and Free Charge!
www.evsolarkits.com
thesmokingman
Active Member
I did not.
Daily vampire drain is not 100W-Hours. It's 100W continuous, which is 2400Wh a day.
Vampire drain in a 2017 (which this thread was created) S/X is about 7 miles a day, which at 300 wh/mi is 2,100wh. Hence 100w CONTINIOUS given 24 hours in a day.
Your whole post is broken by a misunderstanding of watts vs watt hours. The multiplier of "5" from NREL means effective hours in the day- a 1000W actual power output panel will produce 5000Wh over the day. But simple math would assume 24,000Wh due to there being 24 hours in a day. This multiplier is not taking the rated output of a panel (which is instantaneous) and both assuming it will be 5X rated AS WELL as going at that rating for 24 hours a day.
Sun itself is just over 1000w/meter in perfect conditions. You will never get better than this. 20% efficient panel is 200w output. With a multiplier of 5, that's 1000Wh in a day. It's not 200w * 5 * 24hours. It' s just 200w * 5 hours.
Vampire drain is over 2X this.
The literal photons that fall on 1/8 of a square meter are 125w in the very best conditions. If you could collect all of those for 24 hours, you'd have 3000Wh. A real 1/8 sq meter panel produces about 125Wh of power over a whole day against 2400Wh of vampire drain. Even a model 3 needs 220Wh per mile, so this won't even give you a mile of range.
ucmndd
Well-Known Member
I don’t see drain anywhere near that. Not even close. Maybe 2 miles/day max.
I disagree completely with this. If it was true, any Tesla left for more than a week or two would be fully discharged. 100 watts x 24 hours = 2.4Kwh. 8-10 miles of range per day? No normal Tesla sees that much vampire drain.
And, I do understand the difference between watts and watt hours.
You have decided to mock me rather than look for a better way to explain a slightly complicated problem.
You're lucky. My 2017 Model X does 10 miles a day pretty often. It depends on what MCU you have and other factors. Again, written in 2017.
But even at 2 miles a day, that's 500+Wh, not 100.
roblab
Active Member
... Really?? I've owned EVs since around 2008 (I had one of the first Teslas built), and I NEVER replaced a 12 volt battery, never touched it on any of my cars, two of which I sold with over 100,000 miles on them. With the car keeping the 12v charged up at all times, there's no reason for them to die. What are you people doing to your batteries???
My Model X with MCU1 did this all the time, and Tesla tells me it's normal. It's much better now with MCU2, which did not exist in 2017.
What kind of vampire drain do you believe a 2017 Model S/X with MCU1 got in watt hours per day in 2017? Realize even it's 500 (2 miles a day) you're still not close with a 1/8 square meter panel, and there is no way vampire drain is only 100Wh per day (4w continuous).
Even the much more modern Model 3 averages over a KWh per day in polls:
POLL: What vampire drain are you seeing on your 3?
Curious what everyone is experiencing for vampire drain
teslamotorsclub.com
And people mention 1-2% a day in a Model S, which is 1-2KWh
What is “normal” vampire drain?
New 2020 MSLR+, my first Tesla. Loving it!! Keeping it plugged in, it charges right up to +/- 313 mi where I have it set (80% of 391, so right on the numbers). However, it seems to lose a mile or so every few hours. I haven’t been monitoring it long enough to figure out a daily rate, but...
teslamotorsclub.com
You didn't use the term watt hours once in your post, despite talking about production over a day. That's very curious, and makes it very hard to read if you are expecting the reader to constantly multiply by 24, and even harder when production is not constant over time, which is why we always talk in Wh, not watts when we talk production. You're also the one claiming 1/8 of a square meter can generate "average 100W total per day year round" when what you mean is 100Wh per day. Which is true. Against 500Wh+ vampire drain per day, much less 300Wh/mile use in motion.
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nwdiver
Well-Known Member
I thought the same. Tesla had been replacing them under warranty when I took the car in for its annual service. I never noticed until the car was out of warranty.
ucmndd
Well-Known Member
Seems very hit or miss. I finally proactively replaced the original 12v in my 2016 at 5 years.
n2mb_racing
Active Member
The 12V failed in my Model 3 after 3.5 yrs, less than 18k miles. I'm glad I don't have one anymore in my Model S.
I helped a friend inspect a new model 3 for delivery yesterday and unfortunately it still had a lead acid battery. That was a bummer. I thought they had switched over to the lithium 12V from the S.
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