solar powered circuit

[jvolt123]

Hey community, so I am trying to put together an early project in my circuiting career. My plan is to hook a solar panel to a capacitor I've got a hold of and then to be able to power a small hobby motor. The capacitors I am trying to charge are little guys I bought and are rated at 5 farad 2.7 V that look pretty much the same as these guys **broken link removed** . The goal I have in mind is to do this with the smallest components I can use give or take ( solar panel , motor ) in hopes to be able to make a small car with like maybe the size of a mouse, just something cool to play with. I have been looking around at solarbotics to see their panels and they seem to be a good size but I don't know what I am looking at in order to charge up my capacitors and be able to run a motor. I'm thinking a panel that gives me 3.5-5.5 V should be good but I don't know and I'm not sure if I need a finite current out of it. Have any of you guys any experience with this and maybe bought some hobby solar panels to play around with?

 

[jvolt123]

Also I mentioned capacitors. I have 3, but I plan on putting 1 into the circuit and having one solar panel to charge it.

 

[ronv]

Probably need to know how much current the motor needs. Usually batteries work better than capacitors for running motors because they hold more energy for their size.
But if you use capacitors you will need to limit the voltage not the current. From the size you are talking about a shunt regulator should work good.

 

[jvolt123]

I will probably buy a motor depending on the rating of everything else. A shunt regulator sounds like a resistor. I have a diode I'm planning on using in a circuit that looks similar to this

 

[alec_t]

You will need a charge regulator, to ensure that the cap voltage doen't rise above the rated maximum.
Be aware that the cap voltage drops rapidly as current is drawn from it to power the motor (unlike a battery, which maintains a fairly steady voltge until nearly exhausted).

 

[ronv]

Well lets see if we are in the ballpark. Lets say you get a solar panel that puts out .15 to .2 watts like one of these.
**broken link removed**

Then you could use a part like this to keep the voltage from going over 2.5 volts and blowing the cap.
https://www.ti.com/lit/ds/symlink/tl431.pdf

You could charge the cap in about 1.5 minutes and run a 60 ma. motor for about 30 seconds. Was that close to what you wanted?

Yes, you need your diode.

 

[jvolt123]

Yes actually , that's exactly what I am trying to do. Thanks for ball park scenario. Now these are the motors I'm looking at **broken link removed** since I need to order to Canada and many other websites are unavailable to me. The ones that I would think seem good to go are the sold out bottom 2. I found this badboy **broken link removed** but I don't know if it's my computer or there website. I can't get the damn checkout to work. For a charge regulator,I also don't know where to look and will it make my circuit much more complicated? Thanks for the insight alec_t, I've heard that yea my cap will loss voltage allot quicker than a battery, but the one thing is that I'm trying to build this without the use of any batteries. My understanding right now is that electricity is always taking the path of least resistance , so what I thought was that once the cap had enough charge , it would then power the motor and be unable to discharge anywhere else because of the diode. What I didn't know is that the cap would blow.My colleague who sold me the caps said there made from all these great materials like aerogels etc and just showed me the simple circuit I showed above with the motor connected to the cap and didn't bring up the reg.

 

[jvolt123]

I just took in that I copied the wrong link for the motors....https://www.digikey.com/product-sea...t=0&page=1&quantity=0&ptm=0&fid=0&pageSize=25 . The bottom 2 of those is what I was referring too. Either way I got my payment through to hobby components and got **broken link removed** their solar panel and a few other motors just to play with

 

[jvolt123]

I'm beginning to read into the shunt regulators. Do these work the same https://solarbotics.com/product/1381/

 

[ronv]

Those would probably be ok. You might need some gears to slow it down.

You can also use 4 diodes to keep the panel voltage below the capacitor voltage.

 

[jvolt123]

I got my gadgets in the mail and I'm playing with a panel now and getting around 2.5v under my cell phone light on the DMM , so I think this one should be okay to test my circuit. I set this up
**broken link removed** and not surprisingly nothing happened. I also tested it with a cap rated at 16v 22uf(microfarad) and tested its terminals for around 2.5v so I think the basics are met here. The motor I tried is pretty efficient and can do 9700rpm @ 1.5v and 17.5ma free draw current 120ma stall. . I also got a Panasonic 1381x IC , the 1381E in the series but I'm not sure how to install this guy and what the circuit would need to look like to get this setup going with this motor. These panels only do around 20ma so I'm also not sure if that will hinder anything here , I got some more powerful ones coming though but I want to set this up with these little panels there like only 27x33 mm or so

 

[jvolt123]

Repost. Can't delete