Teaching about Solar Panels in primary school

bungaro79 · 25-09-2019 9:33pm #1

Hi
I run an after school STEM club in my school and usually every year I try and upskill and learn something new to teach the students. I am looking into solar panels and how to use them in conjunction with things I have already like to power my Snap Circuits or use with my breadboards. I have seen a lot of cheap panels on aliexpress (all my funding comes from donations or sponsorship so try to make it stretch as much as possible!) but I'm still in the early stages of learning about it.
All I want to start with is setting up the panels and hooking them directly up to something like a breadboard to power any given circuit or (not sure if this is possible) hooking it up to a power bank and then using this as power for something else. Its basic stuff but hands on which is what they usually like. If anyone can point me in the direction of a good website for this or any other advice it would be great!
TIA

riffmongous · 25-09-2019 9:37pm

bungaro79 wrote: »

Hi
I run an after school STEM club in my school and usually every year I try and upskill and learn something new to teach the students. I am looking into solar panels and how to use them in conjunction with things I have already like to power my Snap Circuits or use with my breadboards. I have seen a lot of cheap panels on aliexpress (all my funding comes from donations or sponsorship so try to make it stretch as much as possible!) but I'm still in the early stages of learning about it.
All I want to start with is setting up the panels and hooking them directly up to something like a breadboard to power any given circuit or (not sure if this is possible) hooking it up to a power bank and then using this as power for something else. Its basic stuff but hands on which is what they usually like. If anyone can point me in the direction of a good website for this or any other advice it would be great!
TIA

Most basic thing you can do to illustrate the principles is get a very small solar panel, breadboard, resistor and an LED. Then get a little motor and attach some coloured paper to it and watch it spin round, simple stuff.

All the websites I know are based where I live outside Ireland so I'll leave the recommendations to someone else, beyond Conrad.at

Something like this
https://www.conrad.at/de/p/velleman-sol4n-polykristallines-solarmodul-2-v-1713839.html

bungaro79 · 25-09-2019 9:59pm

Thanks riffmongus. One question about your link. That panel is polycrystalline but I've also seen ones which are monocrystalline. Whats the difference between them??

riffmongous · 25-09-2019 10:15pm

bungaro79 wrote: »

Thanks riffmongus. One question about your link. That panel is polycrystalline but I've also seen ones which are monocrystalline. Whats the difference between them??

Efficiency is the biggest thing.. which practically for your application will probably mean price and number of panels you need. For larger applications the lower efficiency of poly will mean you need more space to achieve the same output as with mono

There is also a third kind too, an even less efficient one called dünnschicht in german, (should translate to something like thin-layer in english), but because of it's lower efficiency it will be cheaper and might work well for you since space isn't an issue

example, compare these 2 in physical size (länge and breite), weight (gewicht) and efficiency (wirkungsgrad), and then Voltage and Watts because they have the same price
https://www.conrad.at/de/p/sygonix-sy-vru214-2-duennschicht-solarmodul-2-w-6-v-1780539.html
https://www.conrad.at/de/p/sygonix-qutq6-15-polykristallines-solarmodul-0-9-w-6-v-1719872.html

You can find all the results here to give you an idea of what's out there
https://www.conrad.at/de/search.html?searchType=SearchSuggest&categoryId=0509082&sort=Price-asc

bungaro79 · 25-09-2019 10:21pm

Cheers riffmongus. Think I'll start with something basic like you mentioned above but I've seen some solar powered USB chargers which might be a nice DIY project

riffmongous · 25-09-2019 10:36pm

bungaro79 wrote: »

Cheers riffmongus. Think I'll start with something basic like you mentioned above but I've seen some solar powered USB chargers which might be a nice DIY project

There are some nice practical ones for charging your phone alright, you can also get nice little solar based toys too for the younger kids

https://www.conrad.at/de/p/sol-expert-airstream1-solar-boot-1818584.html

Good luck with it!

Turbulent Bill · 25-09-2019 11:07pm

Sparkfun have some nice solar projects and kit (like https://learn.sparkfun.com/tutorials/sunny-buddy-solar-charger-v13-hookup-guide-), though it mind end up expensive if you need multiple kits. Good for inspiration at least.

A simple LED hookup on a breadboard sounds like a great start.

bungaro79 · 27-09-2019 10:25pm

Thanks guys, 2 great websites there!

bungaro79 · 11-10-2019 1:58pm

Hi again

I have been trying to teach myself circuit basics over the past few weeks as I think I am after finding the right project to do with my class (https://www.instructables.com/id/DIY-Solar-Phone-Charger-5-Portable-100-Batter/).
One thing I'm hoping someone can explain in laymans terms is, in the above project the guy who did this said not to use this with tablets as they were high amp devices. What does this actually mean?
Does the voltage, mAh and wattage of the solar panel make a big difference?? Obviously I don't want to ruin any batteries or devices of things I'll be testing it with before I bring it into the classroom!

whizbang · 14-10-2019 12:02am

Think of the solar panel as having a high internal resistance.
re power,
Max current means 0 volts = 0 power.
Max Voltage means 0 amps = 0 power.
so the maximum power is somewhere in between those 2 extremes. Its anyone's guess where this point is on voltage and current scales. MPPT's are used in comercial systems;

MPPT stands for Maximum Power Point Tracking, a technique to regulate the charge of your battery bank. The function of an MPPT charge controller is analogous to the transmission in a car. When the transmission is in the wrong gear, the wheels do not receive maximum power. That's because the engine is running either slower or faster than its ideal speed range. The purpose of the transmission is to couple the engine to the wheels, in a way that lets the engine run in a favorable speed range in spite of varying acceleration and terrain.

Let's compare a PV module to a car engine. Its voltage is analogous to engine speed. Its ideal voltage is that at which it can put out maximum power. This is called its maximum power point. (It's also called peak power voltage, abbreviated Vpp). Vpp varies with sunlight intensity and with solar cell temperature.

Re Tablets; they usually dont have a low current charge mode. Older phones used a sort of MPPT system, newer systems use a communications link to negotiate charge current. If there is no communications, then no current..!

Teaching about Solar Panels in primary school

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