100 Solar Panels for £9.99!

[DBK]

Thought I'd got a bargain, 100 solar panels on eBay for just £9.99!

I may have misread the dimensions....

But soldering 6 together gives me 3.5 volts and under a cloudy sky a short circuit current of about 70 mA.

Not sure about my soldering, the panels have discoloured. I fear I am going to have to buy a proper soldering station with a hot air gun and use soldering paste.

This is the voltage regulator, which has a 3.3V output over a range of input voltages. This is going to be the solar regulator.

The challenge will be getting this to power a Raspberry Pi Zero. The voltage is fine but the power isn't enough so I think I am going to have make several PV arrays and wire them in parallel.

To be continued....

 

[Abacist]

You must be desperate to find something to occupy your time! My patience would not last even thinking about this!

 

[DBK]

You must be desperate to find something to occupy your time! My patience would not last even thinking about this!

What I'd really like to do is send a small balloon about 36" in diameter around the World. Sadly my electronic skills are not up to making the tiny little radio transmitter needed to go under such balloons. Some weigh less than 10g including GPS, radio and solar panels - the same panels I'm using but cut down to make them even smaller. This map below shows the current position of one such balloon on it second circumnavigation. It has gone off google Maps and is at about 86 degrees North at the moment.

 

[DBK]

Curious episode this afternoon. I've ordered a hot air soldering station off Amazon but I couldn't find on Amazon any soldering paste, which is the mixture of flux and powdered solder you use with hot air soldering. But I found some on the RS website and ordered it only to receive an email saying it can only be sold to "professionals". It turns out it is a banned substance because it contains lead and I am not allowed to buy it.

Fortunately, a contact told me where to look on eBay....

'nuff said! UK supplier too.

 

[h1ghway1]

DBK.. absolutely brilliant.. I hope you get the solars to work..

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[Abacist]

What I'd really like to do is send a small balloon about 36" in diameter around the World. Sadly my electronic skills are not up to making the tiny little radio transmitter needed to go under such balloons. Some weigh less than 10g including GPS, radio and solar panels - the same panels I'm using but cut down to make them even smaller. This map below shows the current position of one such balloon on it second circumnavigation. It has gone off google Maps and is at about 86 degrees North at the moment.

View attachment 395046

That is some achievement and I can now see some kicks in that !

 

[DBK]

A bit of an update to this thread. I've now managed, after a few false starts, to get my Raspberry Pi Zero tracker running entirely off solar power using some of these panels. The panels are powering the Pi, the GPS module and the UHF transceiver which is broadcasting on 434 MHz. It's all just a lash up at the moment and there is possibly scope to simply things. At the moment the output from the panels goes through a tiny voltage regulator and there are two capacitors to act as a buffer of energy. On the garden bench it looks like this:

The wonky bit of wire sticking up is the antenna - it needs sorting but it works in the garden.

The signal is picked up by my Raspberry Pi powered receiver in my shed.

This is just using a stubby little antenna but I have a Yagi antenna for longer range, which you can just see in the background.

This receiver decodes the packages of telemetry from the Pi Zero, which look like this:

In amongst other data this shows the latitude, longitude, altitude, number of satellites and internal temperature. This is uploaded to a server (not mine) which displays this on a map:

The idea is to fit all this into an expanded polystyrene box which will have a set of solar panels on the top and bottom so it should work however it lands. A second payload with a camera will be battery powered.

All that remains will be to fill a very large balloon with hydrogen and let it go. I'm not sure when this will be, but it is unlikely to be before September I think. There is much to do first and a lot of testing is required. I've ordered a kite which should allow me to do a bit of testing aloft.

I'm also going to look again at the solar panel set up as I have made it over complicated. The Pi has its own voltage regulator I've only recently learned and can cope with a feed of between 3 and 5 volts. I might also include a small rechargeable lithium battery, the sort used in mobile phones.

Theoretically, this tracker could be fitted in a little box on the roof of a MH but it would need a proper solar panel, the ones I'm using are exceptionally fragile, but a panel of a few watts would probably be enough for the tracker to work even under cloud. With a small backup battery it might even get through the night. But 434 MHz is the wrong frequency. When this is running near the MH the remote locking doesn't work as the key uses 433 MHz and even though this tracker is probably generating no more than 20 mW it blocks out the key fob. You can get transceivers running on 868 MHz which would probably be a better choice especially as this frequency doesn't require a licence in the UK. I'm using 434 MHz as it has a longer range but I might have a play with 868 MHz, especially for the tracker with the camera as the images are downloaded in flight and the higher frequency is better for lots of data.