DIY solar panel from cheap solar cells – Does cheap solar cells works from eBay

Solar energy is the coolest energy source in the world. But because of its cost of energy harvesting systems, it’s not very popular among a lot of people. However, while I was looking for some cheap option for a DIY solar system, I found some sellers on eBay, selling solar cells for considerably lower prices. So after careful consideration, I ordered 100 pieces of solar cells, which cost me a 8.38$ with free shipping. It was branded as AIYIMA 100pcs Solar Panel Solar Cells. However, it’s specification says one cell provide 0.5V 320mA of current with an efficiency of 17.4%. And with that specification I could have maximum of 16W (0.5Vx320mA) from all of the cells combined together. Which isn’t much, but since 0.5$ per a watt is really a cheaper option for me. I’ll add a link below the post to eBay seller if anyone needs to take a look.

In a few weeks I received it with a well protected package including nothing but 105 solar cells. I had to check several of them to make sure they are working and all of them was given me an acceptable result.

Once I had satisfied with cells I had to decide what kind of panel I had to make. After a quick research I found for 12V system I had to make a Panel with peak voltage around 18V and for a 24V system, it’s going up to 36V. The reason behind that is, when a load is connected to the panel, voltage is going to drop as our setup. The more current draw from the load, the more voltage drop is occurring depends on various factors. At least if I am going to charge 12V or 24V battery for storing energy, I need a larger voltage than battery voltage for make it work.

In my situation, I went for 24V system for oblivious reasons. First one is preventing energy lost while transferring. Second one is I have planned to use inverter which work with 24V. The first reason is valid for everyone and in every system, unless if you use bigger wires or something. If you transfer the same amount of energy through wire in different voltage, According to P=IV, lower the voltage, current become higher and because of resistance of wire most of energy become a heated and lost way through the battery. So prevent that happening, we can use wires with lowest resistant, which is thick wires. Or use higher voltage to lower the current which is more likely less energy wasted as heat. In that way we can use thin wires which is more cost effective.

Here are 2 panel systems I planned. For 12V, Its use 36 cells in parallel to create around 18V. And for 24V system, it should be used 72 cells in parallel to get around 36V.

First, I had to solder each cell for connecting them each other. I used, excess pins from LED’s for my previous project for connecting each cell. However, in this process I had to scratch the back side of welding tape a bit of a make surface more appealing to soldering.

However to finish this process you might need tons of patience because of cells are very fragile, you most likely broke every one of them in this process. In my case I broke 20 of cells before the work done. So this might not be very cheap after all. But after a few practice rounds it can handleeasily without breaking.
After prepare 4 of 18 cell panels I used a plain glass to mount them using glue and connect them together for complete the panel.

In testing I was able to get 40V max in direct sunlight average to 38V. To be honest, I wasn’t expecting that much result from it. However, when I connect to load which is 12V DC cooling fan with 0.15A rating on it, the voltage drops 17.6V max to 3.6 V min depend on light intensity of the sun. But at the end, I could able to run that cooling fan with a maximum speed (I guess) without paying any electricity bills.

These cells are working and provide sufficient power for small scale projects. But preparing these cells is very hard. However, I’m planning to go for complete system with batteries, charger, controller and so on, and then I’ll be able to tell whether this cell are cost effective than commercial products or not. Then I can accurately calculate the maximum power they can provide and hopefully I will do that soon.

How Did I Fix Samsung Thin 64gb USATA MLC SSD Hard Drive – Revive From Dead

Months ago I was experimenting with USATA SSD hard drive and use it with my PC for a while. After a few days, I went for a driver update on my system and then System was suddenly frozen. So I had to restart the PC and after that HDD wasn’t recognized by the PC. So I did the almost every trick in the book to get it back to work again, but it was a really dead and nothing could detect that hard drive again. However, I thought it’s a driver update that kills the HDD, but later I found out my power supply is not good as I thought and I had to replace it later.

However a few days ago I had time to look at that SSD Drive again and as expected, it doesn’t show any response when connect to the PC, even BIOS couldn’t detect it. So I assumed it had hardware issues and went to find some resources over the internet. I expected to find datasheet and check it’s for possible faulty units. But unfortunately I couldn’t find datasheet, so I went to check the HDD board without any clue.

First, I checked USATA power unit for getting an idea and I got a low resistance reading for both polarities around 200 ohms and it was odd because of it should be having a one way resistance if it use any of rectifier diodes in the circuit. And I was guessing 200 ohms is acceptable because its drive in only 3.3V so it need lower internal resistance to get more power inside to get to work done. So, according to V=IR it’s draws 15mA in ideal but I had no idea it’s good or bad without any reference.

So I went further on the path for something looks bad and for my luck, I notice something looks like a capacitor, in the middle of path of +3.3V, given me readings of resistor but when the polarity change it’s given me a different reading than first one. So I immediately remove it from the circuit and check it and it’s again given me to the same result.

Since I didn’t have any reference I couldn’t find what that was exactly. So I draw the paths so I can see clearly what it could be.

As it’s clear it could be diode or resistor or inductor or fuse to go DC current through it. Anyway, there is no point of adding a resistor in this place so I could remove resistor from guess list. And also, no point of using inductor here unless frequency filter is needed. Since it’s getting already smoothed DC voltage it could be eliminated from the list. Then there is a possible chance to be it a diode but because of the same reason it doesn’t make any sense. Also adding diode here would add a voltage drop, possibly between 0.7V – 0.3V and it doesn’t seem right. However, it does look like capacitor, but it’s not possible to be a capacitor, so my only guess was it could be some sort of fuse. And it was acting as 1st line defense and my faulty power supply blow it. That all makes perfect sense. The only thing bothering me was, if it was a fuse and it is blow up by higher current it shouldn’t be giving me resistance reading between its terminals.

Anyway, I was out of options and I could not find anything similar to that in other hard drives I had. So I decided to go for fuse and take a risk for already dead SSD Drive. Then I short the paths like if it was a fuse. Then check the internal resistance between GND and +3.3 terminal and make sure nothing shorted in the paths. And then connect SSD Drive to the power and check for unusual heating. At this point I could have tested how much current it draws from the power supply and compare it with before, but I forgot to do that. So I connect SSD HDD to the PC and turn it on. Boom! It worked!

After that, I install windows 10 on the drive, test benchmark and everything was looking good. Unfortunately, I didn’t have any reference about how it was performed before, so I could have compared it. In my test, it was heat up around 400C without any cooling. I’m guessing it’s ok to be heating up without blows up anything.

In summary, this is not universal fixing method for fixing everyone’s SSD hard drives. My point is, you could possibly fix your SSD hard drives by following something similar steps. But you have to be extremely lucky.