Recharging an electric car

[Tyvain]

Hello everybody

Small theoretical questions (here, let's admit that we have an unlimited budget and that the cost / opportunity does not count):

1 / In an environment that provides 3 kWh / m² / day, how much (approximately) of this kind of panel would it take to charge an electric car (V 360/24 kW) in 10 hours?
http://www.alibaba.com/product-detail/P ... 87607.html

2 / Imagine that I have the car and the panels, what will it take in addition to be able to recharge it? (modify the car? A converter for 360V? Intermediate batteries? ...)?

Thank you in advance for your answers.

[Gaston]

1) We lack a little information.
For example, the 10h charge constraint cannot be used because we do not know how to position these 10 hours in relation to the environment (if it is 10 hours from 22 p.m. to 8 a.m., it will not work regardless of the number of panels.
Similarly, an environment at 3 kWh / m² / day is not very precise (it is very weak by standards and we do not know if it is by default power or duration).

Let's try to give an order of magnitude:

The panel given as an example provides 72W for an area of ​​1,122506m², or 64,142 W / m² in an environment at 1000W / m².
Or a yield of 15,59%.

We will therefore assume that it will convert 15,59% of the 3kWh of the proposed environment, it will therefore provide 467Wh per day.

In terms of simple energy balance, to supply 24 kWh in a day, 51,3 panels will therefore be required.

2) Charging an electric car directly from solar panels is always a problem because the chargers are designed for minimum power (and therefore do not withstand cloudy passages in front of the panels for example).
For efficient recharging, it would be necessary to bypass the vehicle charger and connect directly to the batteries, but that generally poses other problems (such as distorting the energy gauge of the car which has not "seen "pass the recharge).

[elephant]

Hence the interest of network injection which adapts automatically.

[Gaston]

Hence the interest of network injection which adapts automatically.

Effectively.
But in this case, the car charge continues even if there are clouds (or even at night) while consuming on the network.
It can be practical just as it can be prohibitive, depending on the point of view ...
And then there are also the isolated sites.

[I Citro]

Good approach Gaston.

The photovoltaic recharging integrated into the vehicle indeed seems irrelevant, even if there have been announcements recently in this direction.

We had proposals for a vehicle equipped with solar cells that we parked under a carport equipped with concentrators (Fresnel lenses) which concentrated the light captured by the large surface of the roof of the carport on the small surface of photovoltaic sensors installed. on the roof of the vehicle.

This proposal is very utopian but provoked the following reflection:

If I put on my vehicle (roof and hood) the equivalent of 2m² of cells, which is nothing phenomenal, and considering that the car is always parked outside and sufficiently exposed, it would receive the following amount of energy :
300Wp or 300kWh / year or 2500km traveled with an electric car such as the Volkswagen e-Up.
On good days, the autonomy of the vehicle (and its consumption on the sector) can be gratified by fifteen km offered by the sun.

This energy can also be used to cool the vehicle batteries and optimize their longevity, but also cool or heat the passenger compartment just before taking the vehicle for a journey.

Most current electric vehicles being connected, offer smartphone / PC applications to control air conditioning remotely.

From a technical point of view, I see the feasibility of such a system by connecting it to low voltage buffer batteries (less than or equal to 48V) which would push the amps in the main battery, either via a DC voltage booster / DC, either via an inverter whose AC output would be connected to the vehicle charger input.

[elephant]

Except for technical and aesthetic aspects , 2500 km free per year, I take. or for example 600 wh in air conditioning before taking the car after the job in summer, I am quite favorable!

A supermarket paid more than 500 m² of PV not far from my home (Mestdagh-Champion de Couilet, for those who know). It's great: it's the sun that pays for the electricity in the fridges in summer when they turn the most.

Can you imagine that on a van that makes deliveries in an urban environment?

[Tyvain]

Thank you for your answers.

The purpose of my final question was to study the possibility of carrying out the following project:

Take an electric vehicle and cross a desert without assistance or fuel.
The goal would be to drive in the evening for example (say between 100 and 150 km), then recharge the car during the day by deploying flexible panels. (which would serve to provide shade at the same time)

I had calculated with the ladle that with 30m² of panel it was playable, but I probably underestimated.

Then the converter problem seems very complicated to me. A standard electric car integrating safety systems for charging ...

Do you think such a project would be feasible or completely impossible?

Goods.

[Remundo]

if you have a tarmac road, yes it is playable, but your project complicates matters by taking out electrochemical storage which will lead you to overconsume. It is better to roll over the sun.

If you drive in the sand and the dunes, your project is practically impossible, and also think of the water reserves ... it is not enough to hoe the vehicle.

[Tyvain]

Yes there will be a road, and no danger. Places everywhere to stop, sun, in short the ideal conditions.

So, in your opinion, intermediate batteries are essential for this project?

PS: I don't want to roll over the sun. I really want to drive and then wait for the batteries to charge.

[Remundo]

Good evening Tyvain,

If you have the correct route, it is already "playable".

However, the weight of the batteries will cause you to strengthen the chassis, have heavier tires, and overall more pneumatic drag. The very principle of storing and destocking energy generates additional losses compared to taking solar energy directly to send it to an engine.

What is the point of driving "very fast", exhausting your battery and stopping to recharge ... Or do you only want to drive at night?

Technically and with a budget, a lot of things are possible, but you still need to have precise specifications on the "goal of the game".

Personally, I'm not a big fan of these solar cars. They don't do much.