Same old Experiement. How much power can you get from Solar-Panel-Covered car like Citroen Czero

April 30th, 2013 § Comments Off on Same old Experiement. How much power can you get from Solar-Panel-Covered car like Citroen Czero § permalink

I have already come across blogs and historic articles on “have-a-go” attempts of charging car by Sun, in sunny-rested places like California.

Indeed my interest here, living in London, UK, is not actually to establish the validity of those attempts by establish long-standing interest.

I commute daily, each way, ~10-12 miles depending on traffic and thus route i can take.

I also drive an electric only Citroen Czero model. Small, cuddly 4 seater weighting about a tonne.

On typical hourly charge cycle from 3.5Kwh home plug (13A, 240V) it would deliver some 11-13miles of charge – about what i need.

So, back to my experiment;

Considering my car, like most of your cars, is stationery throughout the day, is it possible to charge the car from Solar panels, installed ON the car, to warrant a safe comfortable ride back, via the same aforementioned 12 odd miles.

Now now, its ambitious, and I’m aware of seasons,  but kid me on this, we get some anticipated 6 months of daylight.

I have also come across some “semi-flexi” solar panels, 135W outputting (ideals), weighting 2.6KG. contrary to typical argument such as it would be too costly (power spent) due to weight of such installation, vs any solar charge such panels generated.

Here are my musings:

Car Watts x Hrs
Required Charge 3500x1hour(12 miles) 3500
Total : 3500Wh
You will need : 292Ah of Battery Power
Solar Panel(s) : 86Watt (assuming 4 hrs sunlight)

Am i being reasonable? do tell me – comment to @evMeerkat on twitter.

Updates: Comments to my musings:

Matt Beard ‏@GettinTwitta3h

@evmeerkat you are out by a factor of 10. You will need 860W for 4 hours!

How to Choose a Solar Panel (from

You will need to make sure that you have enough battery power as well as solar power, You may need multiple batteries (enough to cover the Amps per hour draw (Ah)) and multiple panels (a 160watt solar panel is the same as 2x 80watt solar panels)
If you are planning a big system I would suggest sepaking to an expert for your particular situation, remember this is a guide, different panels have different performance, and batteries are different as well!
For those of you interested this is how we worked it out!

1. How Much Power can you store?
Battery capacity is measured in Amp Hours (eg 17AH). You need to convert this to Watt Hours by multiplying the AH figure by the battery voltage (eg 12V).

For a 17AH, 12V battery the Watt Hours figure is 17 x 12 = 204WH

This means the battery could supply 204W for 1 hour, or 102W for 2 hours i.e. the more energy you take, the faster the battery discharges.

2. How much energy will your appliance(s) use over a period of time?
The power consumption of appliances is given in Watts (eg 21″ fluorescent light, 13W). To calculate the energy you will use over time, just multiply the power consumption by the hours of use.
The 13W light fitting, on for 2 hours, will take 13 x 2 = 26WH from the battery.
Repeat this for all the appliances you wish to use, then add the results to establish total consumption.

3. How much energy can a Solar panel generate over a period of time?
The power generation rating of a Solar panel is also given in Watts (eg 10W). To calculate the energy it can supply to the battery, multiply Watts by the hours exposed to sunshine, then multiply the result by 0.85 (this factor allows for natural system losses).
For the Solar 10W panel in 4 hours* of sunshine, 10 x 4 x 0.85 = 34WH. This is the amount of energy the Solar panel can supply to the battery.

Thus,  to assume that something like:

Electrical Characteristics (+/-5%)*
Rated Power Output:  135W
Optimum Operating Voltage [Vmp]:  24.9V
Optimum Operating Current [Imp]:  5.45A
Open Circuit Voltage [Voc]:  29.5V
Short Circuit Current [Isc]:  5.82A
Cell Technology:  Monocrystalline Silicon
Number of Cells:  44 high-efficiency Sunpower cells in series
Output Type:  36″ MC cable
Approx. Dimensions:  56½” x 21¼” x 1/16″ (1435 x 540 x 3 mm)
Weight:  5 lb 12 oz. (2.61 kg)

may* make wish come true, but As advised, multiply by factor of 10. to make it charge me for 12 miles.

Either that of we have to double th amount of time in the sun. From 4, to 8 hours. Now factor reduces to half, i.e. 5.

Next, It appears that we have to make use of ALL surface area on the car. e.g. Solar Panel of choice above x 5 items.

We are talking 12KG weight gain (beside the extra cables, and fittings) I doubt this is significant as earlier pessimistic correction that overall energy is too limited vs the weight of the panels you have to carry. 


Lets talk Dimensions

Length 144.8 in | 3678 mm.
Width 62.4 in | 1585 mm.
Height 63.6 in | 1615 mm.
Wheelbase 100.4 in | 2550 mm.
Front Track 55.9 in | 1420 mm.
Rear Track 54.3 in | 1379 mm.

imiev, czero, ion model

Either the spec above or i really need to bring my tape measure and actually establish how much surface area do i have to work with…


More updates on this soon…

I seriously need to get into electrical principles, and do a course on this subject.

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