Tag Archives: solar

Review of a 50000mha solar USB Powerbank | testing a solar panel usb powerbank

I have developed an unnatural obsession with powerbanks, I have a large number of them for different purposes.

I decided to start reviewing them to give people information before making a purchase, often these cheap devices are sold with a number of features which may or may not be useful of even work at all.

So ill start off by listing the locations where you can purchase them, and the costs.

So for this experiment ran two tests, one with the unit on its own and another with an external USB Solar panel attached to assist in the charging.

Here are the links and costs to the products.

  • Powerbank 50000mha dual usb with LED – $24.99
  • Solar Panel 6volt 3.5watt – $7.38

01. The first test was conducted in the following way. I put the powerbank in the sun during an overcast day for six hours facing North (10am-4pm). Then I connected it to my phone can checked to see how much charge was given.

Results: 12%

Conclusion. The charge isn’t that much, but its enough to get you out of a sticky situation.

02. The second test was conducted in the same way as test one, but also installing the Solar panel listed above.

Result: 40%

Conclusion: I’m impressed, 40% is decent charge levels for 6hours in the sun.

Overall Conclusion:

Im pleased with this product. I have tested it in the rain, I can confirm its was resistant. Its a tough product, it needs to be if its going to survive in my world.

How the CMTPO2 solar charge controller works. | how to use a cmtpo2 solar panel controller

I bough a solar panel which came with a CMTPO2 charge controller.

Unfortunately the instructions were difficult to understand, and faultfinding was impossible, so I have written this post to give you a quick understanding. 

Relate the letter in the below picture to the functions.

a.

  1. Solid green light: This means its collecting energy from the sun and charging
  2. Flashing green light: This means it collecting energy from the sun but no required as batteries are full and not required by load device.

b.

  1. Three solid red lights: Batteries are full
  2. Two solid red lights: Batteries are half full
  3. One solid red light: Batteries are approaching empty
  4. Flashing red light: Batteries are dead not providing any power

c.

  1. Solid green light: There is a device connected and drawing power.

d.

  1. Connecting the device which requires power.

e.

1. Connection to the battery

f.

  1. Connection to the solar panel.

Building a 24/7 Raspberry Pi using offgrid power. Solar and battery operated outdoors. | raspberry pi 3 iot 24/7 solar panel battery charge cmtp02 wifi mesh node weather station

After doing months of research and experimentation I have finally completed my task. Building a raspberry pi with the ability to running 24/7 outdoors off grid using batteries and solar power.

Why? There are thousands of applications for this kind of setup, here are some I would like to experiment with in the future:

  • Mesh network node, over a wide area
  • Weather station
  • Outdoor wifi hotspot
  • Outdoor wireless camera node
  • Wifi bridge

Priorities. Project objectives were,

  • Cheap
  • Waterproof
  • Heatproof
  • Robust
  • Simple

Considering this was a experiment / proof of concept this was put together using things I found around the house, obviously if this was built for commercial applications the housing would need to be built using steel and this would make the costs go up. This was built using the following components and costs:

  • Raspberry Pi $49.50
  • Raspberry Pi Case $10.85
  • Micro USB Cable $1.00
  • 12v to USB Converter $5.11
  • Solar Charge Controller CMTP02 $12.00
  • Solar Panel 60Watt $59.98
  • Bucket
  • Battery AGM12-20 $65.00
  • Total: $203.44

Once I had all to components I used Styrofoam which I found in my garage to build a base which will be located at the bottom of the bucket, the objective will be to hold the battery in place and also insulate it form the suns heat. see below.

 

 

 

 

Once we have a nice tight fit, we’ll install it in the bucket. I will also use the leftover Styrofoam which I have crusted into small pieces to fill the gap between the battery and the wall of the bucket. This will stop any movement and will also provide insulation to the battery itself.

 

 

Now we need to take note, I have completed a similar experiment here where I tested the battery and Raspberry Pi alone without solar or controller. I managed to get 4 days uptime.

Next we will need to run the wires required for the solar panel, I drilled a hole at the bottom of the bucket and brought the wires up to the top. I did this because if water comes through the hole it will stay at the bottom and not harm the electronics.

 

Next we make another circle with the Styrofoam and fit it on top of the battery, this is where we will house the electronics. Its the safest place as the lid will be water and air tight.

 

Now we can connect the Solar controller CMTP02 to the battery and to the Solar panel, finally onto the 12v to USB controller.

 

Bringing it to life! Install the raspberry and have it connect to my home wifi network. Then seal the bucket and setup somewhere in the backyard where it will get the most sun,facing North (In Melbourne).

Now Im will testing this setup, it should run forever like this. During my first setup run, I had connected the solar panel the wrong way due to bad color coding on the cables. Now that its fixed its been running for three days and the battery is currently on fill charge.