size of solar cell

[plukcc]

just curious to know how big will the solar cell be, if we want it to full charge a empluse R in 6 hours
will it be as big as a football court? 

[Virtually Yours]

So not being an electrical engineer, maybe our resident electrical engineer could correct me if I'm wrong.
We know we need 9.3 kWh to fully charge the Empulse so let's round it up to 10 kWh. We want to be able to charge 10 kWh in one day and for the use of the link/calculator attached that would be 10 kWh per day x 30 days or 300 kWh per month. The map gives you a good indication of how much "peak" Sun light you may get per day. I'm in FL so it's says we get 4 hrs of peak Sun light. That doesn't seem right to me but whatever...

http://www.affordable-solar.com/residential-solar-home/Residential-Calculator

If 1 - 250 watt solar panel produces 250 watts per hour, 4 - 250 watt panels produces 1 kw per hour and I have 4 hrs of usable peak Sun light then I would produce 4 kwh. I need 10 kWh. So I need 10 - 250 watt solar panels to produce 10 kWh of electricity in 4 hrs of peak Sun light. Which seems to work perfectly if I'm charging on a level 2 charger.

will it be as big as a football court? 

The panels I've been looking at are the LG 250w Mono panel. Panel Dimensions: 64.56" × 39.3" × 1.38"
Of course it depends on how you arrange the panels to obtain the best possible exposure.

[BrammoBrian]

just curious to know how big will the solar cell be, if we want it to full charge a empluse R in 6 hours
will it be as big as a football court? 

I think it's important to remember that you are not attempting to charge "real-time" with power from the sun as this would take a massive amount of solar panels.  What you'd prefer to do is to store the power in a battery bank over the course of the day and then discharge that bank of batteries into your bike as needed at a much higher rate than the rate at which you can capture the energy. 

If you can't install a system with a battery bank, I suppose the next best thing is to install a system that simply interfaces with your household electrical and offsets the energy used by your bike.  I.e... you charge from your standard household electrical, but the household electrical is offset by the solar panels.

[oml]

well, lower limit would be (perfect solar cells, on the equator at noon, perfect loading efficiency):  1.14 square meters.
http://www.wolframalpha.com/input/?i=%289.31kwh+%2F+6h%29+%2F+solar+constant

i dont really know what youre after:
a) a quick estimation based on power ? then about 10-15 m^2 which should be a reasonable sized roof (a rought estimation would be lower limit * 5 (cause of nonperfect panels with efficiency about 20%) * 1.3 (youre not living near the equator, are you?) * 1.4 (its not always noon) * 1.3 (loading / other electrical inefficiencies))

b) or a over-a-year-average-estimation based on energy (look at VYs post for that)?




a) gives you the sad insight that it would be very, very hard to achieve nice cruising speeds on a car by solar input alone, even with perfect conditions :|
my father once build an experimental leightweight aerodynamic vehicle for a contest going from munich to northern italy, but the average travel speed achieved by the winner was no higher than 40-50 km/h.

[kingcharles]

Last year a Dutch university team participated in (and won) the solar challenge "cruiser" category with a car that seated 4 persons and was powered by sunlight obviously.
Top speed with 4 passengers was around 120km/h (75mph) if I remember correctly.
Average speed during the 3000km challenge was 72km/h!
That car (named Stella) was made road legal in the Netherlands which is not easy...

Here is the link to the website: www.solarteameindhoven.nl/en/pages/car

Once you go EV, gas is history!

[EmpulseRider]

This app will do the calculations for you, and then some:
http://www.empulsebuyer.com/pvCalculator.php

[Shinysideup]

This app will do the calculations for you, and then some:
http://www.empulsebuyer.com/pvCalculator.php

WOW! Way cool 

[oml]

Last year a Dutch university team participated in (and won) the solar challenge "cruiser" category with a car that seated 4 persons and was powered by sunlight obviously.
Top speed with 4 passengers was around 120km/h (75mph) if I remember correctly.
Average speed during the 3000km challenge was 72km/h!
That car (named Stella) was made road legal in the Netherlands which is not easy...

Here is the link to the website: www.solarteameindhoven.nl/en/pages/car

Once you go EV, gas is history!

Wow, very cool! I didnt know there was still some active research in that area with that impressive results (well, Australian desert sounds a bit flatter and sunnier than the alps, but 70km/h crusing speed is quite nice indeed.).
I forgot to mention that my fathers efforts were late 80ies, early 90ies and therefore was restricted to lower-eff-solar-panels from that time (I think norm efficiency was about 14-16% at that time?).

[protomech]

The Cruiser Class for the 2013 World Solar Challenge did allow overnight charging. 3000 km over 4 days, 750 km (468 miles) per day.

The absolute mass of cells was constrained (63 kg lithium-ion = a reasonable maximum of 15 kWh with panasonic 240 Wh/kg 18650s), as was the charge power available (230 V 10 A).

Even with overnight charging as a supplement, though, the vehicles have to be very very efficient .. for example, suppose a vehicle averaged 100 Wh/mile * 468 miles = 47 kWh energy used during the day .. so they'd need to collect 2/3 of that from solar cells.