Powering a mini R/C car by solar power

[Cyclone]

Hi,

I bought one of those mini radio controlled cars. I took it apart and noticed it only uses a 100mAh1.2v bat. I was wondering if there is any way to use solar cells and transistors to up the current enough to power the car. I was hoping to use those small solar cells found in calculators and just connect them in series are whatever.


Thanks for the help.

 

[Nigel Goodwin]

How long do the existing batteries last?. Solar panels provide incredibly small amounts of power - and the specs are given at exceptionally high amounts of sunlight (think Sahara desert at midday). Those used in calculators only produce a few milliamps (if not microamps!), you would need a lot to power a car.

 

[Cyclone]

hmm the batteries last about 15minutes when fully charged. Those solar cells are small and give about .5 - 1v so i was thinking i could use 5 of them and convert some of the voltage into more current or something. 100mA isn't alot of current. I probably could get away with 75mA and still have the car run decently.

 

[Klaus]

You would need a solar panel several times the size of your mini car to produce 75mA @1.2V. Is that what you want?
How about building a solar 'docking station' with a reasonable sized panel where you can park your car for a recharge?

 

[Klaus]

You would need a solar panel several times the size of your mini car to produce 75mA @1.2V. Is that what you want?
How about building a solar 'docking station' with a reasonable sized panel where you can park your car for a recharge?

 

[coyotesden]

post:

Even if you had enough panels to power the tiny little car, the weight of the panels would probably be the problem.

 

[Nigel Goodwin]

hmm the batteries last about 15minutes when fully charged. Those solar cells are small and give about .5 - 1v so i was thinking i could use 5 of them and convert some of the voltage into more current or something. 100mA isn't alot of current. I probably could get away with 75mA and still have the car run decently.

If it's lasting 15 minutes, with a 100mAH battery, then it's probably taking something like 400mA. As you say, it's not a lot of current - but it is a lot for a solar panel. A quick glance in the Maplin catalogue shows a panel 95x65mm as 400mA at 0.9V - don't forget, these figures are absolute maximums, outside in very bright direct sunlight.

I presume you've already got the calculator panels?, connect them up and try them.

 

[pike]

Why not put in solar motors, they consume alot less current. But your gonna have to find the right size ones as well.

 

[Cyclone]

hmm I doubt i could find a solar motor that is small enough.

Well I got some solar cells that are 4x2 cm and offer 0.55volts and 0.3amps. that amount of current should be enough shouldn't it? These solar panels are only .25mm thick and weigh very little.

It should be possible to connect them in parallel to get the right amount of current?

 

[Johnson777717]

Connecting these panels in parallel would give you more amperage, yes. The panels are just like batteries, in parallel, you get more amperage, in series, you get more voltage.

I bought a pretty good sized solar panel, to mount on the dash of my truck. It's somewhere around 10 inches by 3 inches. I hooked it up to a small PC fan, to see what kind of amperage I could get. I think I only got about 400 milliamps, or was it 800 mah? I don't remember.

 

[Cyclone]

Well I tried connecting 6 of them in parallel and tried combinations in both series and parallel but it doesn't give me enough power for some reason. Its enough to turn the wheels but not enough to move the car once I set it on the ground. hmm.

 

[Nigel Goodwin]

Well I tried connecting 6 of them in parallel and tried combinations in both series and parallel but it doesn't give me enough power for some reason. Its enough to turn the wheels but not enough to move the car once I set it on the ground. hmm.

Try measuring their output - also, what sort of light are you using?. It needs to be outside, in extremely bright sunlight - think Sahara desert at midday!.

 

[Cyclone]

I am using a grow light, its one of those spot lights. Its extremely bright and I have the solar cells like 2 inches from the light so it should be getting enough light.

These are the solar panels I am using.

http://www.radioshack.ca/estore/Product.aspx?language=en-CA&product=2760124&category=IC's+%2f+Leds+%2f+Connectors+Miscellaneous&catalog=RadioShack

the model number is 276-124A

The car must be drawing an extreme amount of current from the battery. hmm

 

[Nigel Goodwin]

I am using a grow light, its one of those spot lights. Its extremely bright and I have the solar cells like 2 inches from the light so it should be getting enough light.

It's probably far too weak - you need to be outdoors in extremely bright sunlight to get the most out of a solar cell - or use vastly greater surface areas. Using a multimeter you could measure their output, but under those conditions it's going to be a tiny percentage of their rated output.

A UK TV program called 'Technogames' held an indoor solar car race, they had an asolutely massive lighting array in order to do it in doors. You know how bright the lights are that TV studios use - they had them packed side to side down the entire course - I hate to think what electricity they used.

 

[bmcculla]

I've heard of people using the solar pannels to charge a Capacitor and then discharging the cap into the motor. This burst of energy is enough to move the car forward a bit. Just repeat to keep the car moving forward.

Brent

 

[Electric Rain]

Since I don't know the specs on the mini car you're talking about, I would suggest building your own car. You can use these solar cells: http://www.allelectronics.com/cgi-bin/category.cgi?category=565&item=SPL-60&type=store With these motors: http://www.allelectronics.com/cgi-bin/category.cgi?category=400&item=DCM-166&type=store. Then just slap those two motors on some wheels with some kind of body, get some front wheels as well, and mount 2-4 of those solar cells to it and you should be good to go! But if you really want to use those mini cars, then I'm going to need a little more detail before I can (try to) help. :wink:

 

[Cyclone]

Thanks Electric Rain those links were helpfull.


hmm I don't know much about the specs of the car. I bought it at Wal-mart and it’s an "X.Trek" car made by Silverlit Electronics. The car uses a "B01 100mAh1.2V NiMH" battery. The battery takes about 3 minutes to fully charge and lasts about 15 minutes before it needs a recharge. The car also operates on the 49MHz frequency and uses 2 really small motors to move the car. the motors are slightly smaller then those common pager motors.