Science Buddies: "Ask an Expert"

I need help trying to build a solar powered car. I know how solar energy works, I just need to know how to set up the connection of the solar board to the electric motor. I'm thinking that you connect the two wires to the board then connect them to the engine, which will then spin on the back axel gear which will result in the car moving foward. Now I could be wrong but I could be right. please post soon.




bluefox609

Sounds right to me. Maybe a simple experiment is the answer. I guess I'd be inclined to use a battery to test the motor, just to be sure that it is working. Then, if there are any problems, you will know where to look.

Thanks for that info, but do you know where I could possibly find a small solar panel? Also do you know I hook\connect the wires to the solar panel?





thanks for the help,
bluefox609

Hi - I'm hoping an expert will chime in with answers about your questions regarding the connection issues.

I noticed, however, in a search of Science Buddies science fair projects that there is one that references a small solar panel, so I wanted to pass on this link in case it is helpful:

https://www.sciencebuddies.org/science- ... p036.shtml

The first item in the "Materials" section is for a small solar panel.

Amy
Science Buddies

We can't easily answer your question about how to make the connections to an arbitrary solar panel. It depends on the specific solar panel you end up using. The part number in the project that Amy referred to comes with 6 inch wire leads (red and black). In that case, you hook the wires from the solar panel to whatever you want to power.

Before you go and buy this specific solar panel, you need to determine if the motor you plan to use will run on 3VDC at 100 mA or less. If it won't, then this panel is not the one to use. In fact, you need to carefully match the solar panel and the motor with your vehicle (what you want to move) or it isn't going to work very well.

Caution: I am not recommending this motor or this company, I'm just using it as an example of what the specifications meanhttp://store.sundancesolar.com/smmoforsopr5.html
This motor supposedly requires 100 mA start-up current. Motors take more current to start. Starting current specs without specifying a torque aren't very meaningful. Locked rotor current (more torque than what the motor can deliver) is a more meaningful number. If your solar panel can deliver the locked rotor current, then it has enough power to start the motor under any conditions where the motor could start.

"Good torque" - not your scientific or engineering data - buyer beware kind of claim!

300 rpm @0.5V - this is probably a no-load free run speed
15 mA no load.

If you can come up with the proper "gear" ratio and an efficient method of transfering the power, this motor might be able to be used and it appears to be compatible with the 3 VDC 100 mA solar panel.

http://store.sundancesolar.com/dcmot5vto3vf.html This is a less expensive motor. This motor requires approximately 100mA start-up current, and runs at about 50 mA with no load. Low torque, high rpm's. Again, not much in the way of specifications. This motor takes far more current than the previous one for no load conditions. If you look at the solar panels this site recommends, they all have lower voltage and higher current than the 3 VDC 100 mA version.

If you look closely, you will find that the 1.5 VDC 200 mA panel and the 3 VDC 100 mA panel are identical except for how they are wired (parallel vs series connection within the array).

BTW: I found these panels and related motors by putting "Solar panels for experiments" into a google search engine and picking the first site that came up. You should look at some of the other search results to see if there are better components for your purposes.