Many people have asked the same question. Many publications had a similar answer.
It’s not worth it.
Take a Tesla Model 3 as an example:
the covering surface area is too small (the roof only);
the PV efficiency is still low; the sun doesn’t fall straight onto your car that most sunshine was reflected away;
it takes days, if not weeks, to recharge your vehicle fully (typically 8 to 10 days at least with a good sun)
It’s all true. It may take another ten (or tens of) years to get us there. It requires many technological breakthroughs to achieve.
Took Too Long To Recharge
Why do we need to recharge it fully? Do we drive till the battery depletes every time we use our EV? Or, does EVERYONE drive at least 3-400 km every day?
Over 90% of vehicles worldwide drive between 25-50km per day and park between 10 am – 4 pm, where solar irradiance is the best. Over 50% are (or can) parked right under the sun.
If the solar panel can recharge a portion of our EV every day, why not? Isn’t that similar to fueling up a little every day at a petrol station for our ICE (I bet no one does that), except that we do nothing by just leaving our EV under the sun?
This is VIPV – Vehicle Integrated Photovoltaics, SAEV – Solar Assisted Electric Vehicles. It is just not yet a “Solar Car”, or commonly known as Solar Powered Car or Solar Powered EV nowadays.
There are "Solar Car" in development, such as Lightyear One, Aptera, SONO Sion, etc. They claim you could get an average of 18 - 24km a day even on a not so sunny day. It doesn't seem a lot. So, what does 18 - 24 km would give us.
For example, let’s say you drive a Model 3 Long Range Dual Motor, with 460km range.
Over the year, your approx. Daily Travelling Distance is 35km, and the battery depletes in 13 days.
If your EV has solar installed to assist daily recharging, say, an average of 18km mileage gain per day over the year. The Model 3 battery will last for 28 days from 13 days, and the driving range increase to 971km from 460km.
If the solar system increases to 24km mileage gain per day, your battery will last for 41days and 1423km driving range. That is, under 10 recharges need for the whole year.
So Much Benefits. Why Not?
So, is Range Anxiety, Charging Frequency still significant issues? A monthly charge from a shopping center might be good enough if you don’t have a home charger. Let’s not mention
it might take away the increasing pressure from the growing EV uptake to the electricity grid in the future;
Greater penetration of EV uptake to people without home charging solutions; and
billions of tonnes of CO2 reduced by switching partially to renewable energy from the sun.
Of course, it doesn’t help much for long-haul EV drivers of 100km+ daily driving. Remember, people around the world drive only 25-50km daily, on average, only occasional long-haul driving of 100km+.
Is Solar not worth on EV? Well, I think the real questions are:
How much surface area is available on your vehicles for solar panels?
Is this necessary to do solar recharging while driving since most people have their car parked during the day?
What is the time and how long do you park your EV?