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Electric car that charges itself

sonomotors.com

411–418 of 418 posts

Re: Electric car that charges itself

#411
post #314

Earlier quoted context omitted.

And this is considering a car not made for this. A longer or van like model would have more surface. I often wonder if slow small buses wouldn't be possible on solar.

If you want to look at the limits of what physics seems to allow (cost practicality be damned), look at things like americansolarchallenge.org winners. They even have a multi-occupant-vehicle class nowadays. The 2018 MOV winner ( https://www.americansolarchallenge.org/the-competition/ameri... ) logged 1762 miles over 58.4 hours, or about 30mph average pace (with a 16.8kWh battery, but no external charging, just the a…

late reply, but thanks a lot for this

Re: Electric car that charges itself

#412
post #407
post #401

Earlier quoted context omitted.

What is the scammy part? That’s what I don’t get about the (pretty angry/sarcastic) comments being made. The technology is there, the math checks out. You can argue the range is not useful, but for my particular case even 10km/day would satisfy my needs through most of the year. Here is an article with more numbers on the solar charging: https://sonomotors.com/en/blog/park-the-sion-in-the-sun-and-...

This meets the textbook definition of snake oil. Electric cars are great. If they can be solar powered, also great! Solar paint — sure, go for it! Selling it as "the car charges itself" — really, no. That is dishonest and scammy. The writeup just anchors this conclusion with excessive verbiage, itself a red flag, vague numbers about ideal conditions, and enticing but deceptive misdirection about oh-my-gosh we don't w…

The car does charge itself, maybe not at the rate you want it to. That doesn’t make it a scam.

There’s nothing else I can say at this point. Are you willing to dispute any of the figures or technical claims or just wishy-washy handwave the whole thing away?

Re: Electric car that charges itself

#413
post #167

Earlier quoted context omitted.

There are also flexible CIGS panels which are not fragile and conform well to curved surfaces and are incredibly light weight. I have 960W mounted on my short school bus conversion and am able to run fridge 24/7, water pump, lights, and an induction cook top and have yet to fully drain the two lithium batteries I got. If any community is aware of the advances made in consumer solar recently it's the skoolie/vanlife f…

Bus roofs are much better for solar than compact cars and you have a use for that incidental power in a way a car does not. As for the car, I imagine people will burn the energy and more by turning on the air conditioning when they get into their hot car that they intentionally parked in the sun. Did you glue(/etc) the panels to the roof or did you have to mount them on standoffs?

I used VHB tape underneath and Eternabond tape over seams to prevent wind from getting underneath - each 60w panel is 2-3 pounds so very light compared to more common panels that need to be structurally mounted to the frame.

Re: Electric car that charges itself

#414

Earlier quoted context omitted.

I agree that in many cases an extra dollar of battery capacity provides more utility than an extra dollar of solar charging. But I did have one of those niche applications a while ago: I used to travel for work and often left my car parked random airport lots for months at a time which meant I occasionally came back to melted cassette tapes and a dead battery. In that case $100 of solar panels to run an exhaust fan a…

This brings back memories of slowly dying car alarms back in the 90s. I probably come across as being more anti-solar roof than I am. Mostly just feel like this isn’t a feature I’d make a purchase decision on and wouldn’t likely pay too much for. I was reading on the Tesla forums about just bringing a portable solar array for camping and it’s weirdly a lot more complicated than you’d think. Perhaps having it integrat…

Interesting, I hadn't know that about Teslas. On a Prius you can mount a ~$50 12V solar trickle charger on your dashboard, possibly with some rewiring [1] to keep one of your 12v sockets live, and it's even easier on older trucks. I'd imagine that the smarter the car, the harder it is to make those kinds of modifications. Even so, an optional "solar package" that integrates cleanly with the dashboard (or roof) seems like it might have broad appeal.

And if your only goal is to use it as an excuse to talk to your friends about having solar panels in your car then a small panel makes even more sense -- you can talk almost as much about a small panel as a large one for a fraction of the cost.

[1] e.g. https://www.coastaletech.com/power_outlet_mod.htm

Re: Electric car that charges itself

#415

Earlier quoted context omitted.

There are also flexible CIGS panels which are not fragile and conform well to curved surfaces and are incredibly light weight. I have 960W mounted on my short school bus conversion and am able to run fridge 24/7, water pump, lights, and an induction cook top and have yet to fully drain the two lithium batteries I got. If any community is aware of the advances made in consumer solar recently it's the skoolie/vanlife f…

> an induction cook top You make it sound like you're using a lot of power in that bus, but an induction cook top is at most 2-3 KW. That is 4 horse power. If you want to crawl at 5 mph that might be enough (but not for a skoolie anyway). Cars have a huge power-plant under the hood. 100kW per car, at least. All the cars in a city have far more power than the power plant that supplies the city. Think 10k cars (town)=…

Are you assuming that the sunlight needs to directly power the car?

The idea, and especially with the car in the article here, is that your car can charge over the course of a few days.

The power for electric cars is delivered from the battery. The Chevy Bolt for example has a 60kwh battery. If you have 1kw of solar, it will take you 60 hours of sunlight to charge that battery assuming the efficiency of those cells is close to what they're rated for.

The car from the article has a 35kwh battery so around 35 hours of sunlight to fully charge on 1kw of solar. If I drive ~100 miles in the city every week, and the car from the article gets the claimed 200-220w/m2 of solar - It's definitely feasible to recoup your entire driving usage by it just basking in the sun when you aren't using it.

Re: Electric car that charges itself

#416
post #412
post #407

Earlier quoted context omitted.

This meets the textbook definition of snake oil. Electric cars are great. If they can be solar powered, also great! Solar paint — sure, go for it! Selling it as "the car charges itself" — really, no. That is dishonest and scammy. The writeup just anchors this conclusion with excessive verbiage, itself a red flag, vague numbers about ideal conditions, and enticing but deceptive misdirection about oh-my-gosh we don't w…

The car does charge itself, maybe not at the rate you want it to. That doesn’t make it a scam. There’s nothing else I can say at this point. Are you willing to dispute any of the figures or technical claims or just wishy-washy handwave the whole thing away?

I’ll go with a hand wave. Bye!

But do let me know when it’s real (just to spell out what that means: physically available for normal consumers to buy, and delivered to them and driven by them in the real world, not as part of any restricted access rollout or prototype) and we’ll look at the empirical numbers then.

Re: Electric car that charges itself

#417

Earlier quoted context omitted.

> an induction cook top You make it sound like you're using a lot of power in that bus, but an induction cook top is at most 2-3 KW. That is 4 horse power. If you want to crawl at 5 mph that might be enough (but not for a skoolie anyway). Cars have a huge power-plant under the hood. 100kW per car, at least. All the cars in a city have far more power than the power plant that supplies the city. Think 10k cars (town)=…

Are you assuming that the sunlight needs to directly power the car? The idea, and especially with the car in the article here, is that your car can charge over the course of a few days. The power for electric cars is delivered from the battery. The Chevy Bolt for example has a 60kwh battery. If you have 1kw of solar, it will take you 60 hours of sunlight to charge that battery assuming the efficiency of those cells i…

I am saying it's not really feasible. To charge a 35kWh battery in 35 hours, you need a constant 1kW. 1kW is a LOT when it comes to mobile PV panels, converted bus campers don't have that much usually.

Earth receives 1kW of power from the sun, per square meter. A solar panel has an efficiency of 20%. So under ideal conditions, sun directly at 90%, no shades, you get 200W per sqm. Now, you have shades, less than 90% angles, dirt, etc. On average in the US, the capacity factor of solar PV farms is 25% (includes day/night changes). You will get less on your car, but let's say you do get 25% capacity factor. That leaves you with 1000 * 0.2 * 0.25 = 50W per square meter, 24/7. In a week that is 8400 Wh per square meter. To charge the 35kWh battery once a week, you need 35/8.4 ~ 4 square meters. 4 square meters is plausible. You could say that the car has more space for PVs, but you kind of have to mount them such that they have a decent angle, otherwise their efficiency drops 10 fold.

In the case of Chevy Bolt, if you have a 1kW of PV panels, used in ideal conditions, you would need 1kW * 0.25 * 240h = 60kW. 10 days to fully charge the 60kWh battery. If you manage to install 1kW (4-5 square meters) of panels on a volt at ideal conditions (tilted 30-35%), then you could drive it 200 miles every 10 days.

On the other hand, if you only drive 20 miles a day, you could recharge at a power outlet and 60kWh would cost you 6 dollars. 6 dollars per 10 days, that means fuel cost would be $219 a year. That is $3200 for 15 years. Is it really worth installing a heavy and complex system on the car if you can achieve the same and better results by just laying the panels on the ground, next to the carport?

I am all for integrating solar PV in a lot more things, like house sidings and windows, but putting it on cars is just a PR move.

Re: Electric car that charges itself

#418
post #167

Earlier quoted context omitted.

Bus roofs are much better for solar than compact cars and you have a use for that incidental power in a way a car does not. As for the car, I imagine people will burn the energy and more by turning on the air conditioning when they get into their hot car that they intentionally parked in the sun. Did you glue(/etc) the panels to the roof or did you have to mount them on standoffs?

I used VHB tape underneath and Eternabond tape over seams to prevent wind from getting underneath - each 60w panel is 2-3 pounds so very light compared to more common panels that need to be structurally mounted to the frame.

Sounds pretty nice and fairly foolproof.

I remember seeing my first solar panel leaning against an old blue and white school bus at a music festival somewhere on the west coast, decades ago. They had a bunch of old auto batteries for storage.

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