Hey guys I have a small problem I can't get my head around (I only have very basic electronics knowledge) and was hoping someone smarter than me could help.
I am looking to power a small robot by solar panels directly driven by the power generated from the solar cells. I understand to do that you generally need a few volts more than the battery that is usually powering said robot due to various reasons.
I also wouldn't mind also having a small battery mainly for sourcing power when the sun is covered by a cloud so it should only need to last 10-15 minutes and is safe for recharging via solar panels.
Now I want to encorporate the solar panels into the design and shape of the body of this robot while still maintaining maximum efficiency.
finally I understand sometimes you are not able to get enough power from solar cells that are able to fit on a body of a robot (they usually end up looking like an umbrella shading the whole robot). In this instance is there a low voltage upscaler I can use to get the required voltage and amps? if it can't be pre-made and bought is it easy enough to make? and small enough to fit in a robot the size of a decent sized hamburger? (yesss robot hamburgers!)
I am trying to make all these components as light as possible to demonstrate the speed and performance of solar panels coupled with the right wiring/technology.
the battery in my robot at the moment is a 3.7V 240mAh LiPo battery
any help for this project would be greatly appreciated and I am looking to do more solar projects once I get the hang of it
Unless there is some form of magic I don’t know about,
Ohm’s Law should come in to play with boost converters. Ohm’s Law boils down to E/I*R. Knowing this you can solve for any of the 3 variables. E = I * R, I = E / R, R = E / I. There is also P = I * E. In simple terms, you can’t get more power out than what you put in. If your solar panels produce 2.5v @ 100mA, you can’t get 5v @ 100mA out of any form of conversion. 2.5V @ 100mA = .25W So, P = I * E or I = P / E = .25 / 5 = .05A or 50mA. 5V @ 50mA is 100% conversion, which is beyond the best case scenario. 80 - 90% efficiency is more reasonable or 5V @ 40mA.
All of the above is ignoring the circuitry required to recharge LiPo batteries.
I know my answer misses answering many of your questions. I thought it still might be useful in the scheme of things.
my first thoughts are high efficiency brushless motors … but to my understanding they don’t tackle voltages 3v+ very well and when they do operate on the designed voltages they don’t get very high rpms.
my second thought was gearing… but that would bring in a whole lot more headaches with torque, top speeds and centrifugal gearboxes but could be possible.
third and final thought is scale… the vehicle in the video looks to be atleast 1:5 scale (70cm x 30cm atleast). With the solar panel being bigger along with the body of the car, that then delivers more power to the electronics and for all we know the electronics could possibly only take up 1/10th of the space under that body.
I think I will do more research in to this particular rc car model… I am determined to make a difference with renewable energy in the hobby/bot building world, even if it starts really small it is a start never the less
the solar eagle uses capicitors to power itself for a very few short seconds while the vehicle is in the shade. what sort of capacitors would be used to do the same with my robot?
I think you mean super capacitors. They are also sometimes called Ultracapacitors. The ones in the link are 4 Farad. You can get many different sizes depending on your budget/requirements. They aren’t cheap.
I am already on this quite a while. So far I got it not working. Even with a voltage of 10V delivered by the solar panel the current is not enought to feed an Arduino plus two servos for the solar tracker.
Stepping up voltage is also not a good solution when motors are involved. From that 10V coming out of the solar panels will drop at least 8V when driving a motor since there is just not enough current coming from my cheap solar cells.
Buffering power in super caps or NiNH batteries is a good way to kep the whole system running for a while.
