Vex Solar Panels

Vex needs to make a Solar Panel pack that lasts forever in the sun :), then make it go to 9v - best motor performance, and be eazily mountable

thats a great idea. imagine just setting your vex bot outside and leaving it there. but you might want to put a timer in it to account for darkness, or use a light sensor. it would run for a long time if you had the proper capacitors. (i think i spelled that wrong, i am not getting firefox, -art)

ya solar panels would be cool plus if you were using your bot to spy on people during the day or an air soft gun bot that would be kool

by the way i spelled cool wrong on purpose dont ask:p

All we need to do is find a company that sells hobby 9 volt solar panels, so we could telll vex…and a extension solar battery(if needed) for the dark.

Great! If you went autonomous with your bot you would have to have experience in programming to avoid shadows though.

Then FVC could have “Solar” comapetitions as well! (Just a thought.)

I got a link to a good solar cell supplier through Google:

A panel that could be used if you had two:

Main Page:

The only problem is that the solar panel above has an output of 22 ish mA. Look at the reprogrammable batteries- I forgot which one, but one of them has a capacity of 2000 mAh. That means it can source 2000 mA for an hour before needing recharging. You would need like 100 of those panels to power a Vex robot permanently (actually, not quite right; the Vex batteries do not last for an hour. The current demands vary greatly).

It’s not just a matter of voltage, it’s current limitations that keep solar panels from working well.

I’ve found several websites with solar panels, but they’re either too expensive($2000) or not the right amount of mA or voltage.

Solar panels would be cool but I would be worried about breaking them.

Solar panels do tend to be fragile and they only convert like 20% of the light that lands onto them into power.

Yeah a long time ago I got the one for the lego robotics. I was dismayed to find out it couldn’t even power the rcx by it’s self.

I got that lego one too and im taking it apart right now and to see if it has any use

Try radioshack I went there the other day and they had some fairly good ones…

You could probobly after a bit of work put them to a bot…

hey guys, I’v been following this forum for a while and the idea of solar panel seemed interesting so I looked into it and I think it might be able to work. If you look on ebay there are people selling solar powered battery chargers that put out like 200mah at like 6v. the vex micro controller only needs like 62mah and 5mah per motor and can work off as low as 6v. I not an expert on how all that works but it seems as if it’s possible

The motor is gonna need W A Y more than 5 ma to run it. More like 500. And you guys are kinda thinking about this wrong, it’s not that the motor “needs 600 mah” or that a panel outputs “600 mah”. Voltage and current are dependent upon the resistance, they are linked quantities that do not exist separately. The motors will run off say 9 volts, but they will draw different amount depending on the load. The max it will take will be when it’s stalling, a number I don’t really want to go to the trouble to determine because I would have to stall the motor. When it’s off it’s taking 0 mA. When freely spinning with no wheel, a little higher. When driving a bot, more still. Get the idea? A solar panel is rated at how many Top mA it will produce. How much it puts out depends on the load. You must have seen that it will output a max of 200 mA, not mAh. mAh means nothing in terms of solar panels, it’s a term that includes time. Batteries have limited output amounts of energy- hence they can produce a certain number of mA (milliamps) for a certain time (hours) hence mAh. Now all this depends on just how much current they output, for example 2000 mAh might mean it could output 2 mA for 1000 hours, but at say 2 Amps (2000 mA) it might could only run for 15 minutes, 1/2 hour, something like that, resulting in a perceived output of maybe only 1000 mAh, even though the sticker says 2000 mAh. Better batteries will output more current for the full rating. In robotics, that’s a whole other issue, because sometimes the motor is on, sometimes the motor is off- the battery generates different amounts of current at different times.

Got all that? :smiley:

Anyways long story short, mAh is a measure of how much total energy is contained in something. In a solar panel, the energy is infinite- it’s the sun, but the panel only converts so much of it to energy. In effect, it has an infinite mAh capacity, but limits on the maximum voltage and current it can produce. You could try it, but I don’t think everything would run very well at 6 volts, much less drawing a max of 200 mA.

I just got the vexplorer for christmas and I’m considering converting the battery component to a solar powered recharger. I think you can solder a 6v solar charger to the positive and neg points on the battery component. Some solar chargers have a a built in blocker diode, but if they don’t you can solder one in to prevent the batteries from losing charge. I am still trying to figure out the mounting of the solar panel. I would also like to figure out how to view through the included spycam on my computer laptop. Any ideas on either project?

SunBot will be a self-powered Vex Based Robot whose mission is to track the Sun anywhere on Earth under all lighting conditions (during sunny, or dark and cloudy days) using Astronomical tables and to collect critical Solar data necessary to produce the next generation solar power generation systems by acting as the guide for hundreds of solar panels located within a one mile radius of SunBot. It also demonstrates how Vex Starter Kits may be used to develop prototype Environmentally Friendly products that can one day help with Earth’s Energy Crisis.

The SunBot assembly includes a 12 Volt Marine panel that is attached to the mast assembly, which is used to recharge a 12 Volt SLA battery. It is mounted on top of my Vex Gilbert IV Robot platform that I made a few years ago as shown in the Vex Gallery photos, proving it a sturdy base and enclosure for SunBot’s electronics and batteries and so that I can move it about my lawn using the Gilber IV’s own 6WD motion subsystem. A Vex Controller and Vex RC remote are used to send it motion commands in order to control it. Telemetry will be sent up to a mile away (line-of-sight) to a remote laptop for data collection and analysis and will receive SunBot commands from the laptop using an XBEE Pro Wireless UART at 115200 Baud, 8-Data Bits and 1-Stop Bit.

SunBot Photo

Gilbert IV Explorer Photo

SunBot’s features will include the following items (if I get to the next phase):

  • Point the solar panel 0-360 degrees Azimuth, within +/- 1 Degree resolution
  • Tilt the solar panel +/-90 degrees Elevation, within +/- 1 Degree resolution
  • Use GPS to obtain SunBot’s latitude, longitude and altitude
  • Vex Controller
  • Vex RC Remote
  • 7 Vex Motors
  • Vex Starter Kit metal parts
  • 1 Microchip PIC32 32-Bit microcontroller
  • 2 Microchip dsPIC30F4011 motor controllers
  • 1 Microchip Temperature Sensor
  • 1 Humidity Sensor
  • 1 LCD Display
  • 2 XBEE Pro Wireless UARTS](

one thing that we need to keep in mind here is that if you somehow manage to overcharge the battery with the solar panel, you’re going to fry it. So we’ll need something to watch the charge level.

i forget where, but i had a hold of a robotics magazine that deals specifically with schools and found that they offered lots of solar cellss…

plus we may be able to get some used ones off of a university that participates in the solar car race… discounted? Why not?