My latest solar panel project

[Kebast]

Here's a look at my latest homemade solar panel. Just had new windows put in the house to replace the original 1977 version. I saved a few of the better ones. Did a test run using some broken cells. No encapsulation for these though.

2013-04-02150725_zps33b68e58.jpg

[bcroe]

Latest

Are you getting out 18V open circuit? How much short circuit current? Panels I assembled
usually had bad cells, which had to be shorted out for best current. Bruce Roe

[Kebast]

Are you getting out 18V open circuit? How much short circuit current? Panels I assembled
usually had bad cells, which had to be shorted out for best current. Bruce Roe

I get 19.5 volts open circuit. I put in one extra cell because I had room and to help overcome the Schottky diode voltage drop..
I have an amp meter on the way, I'll let you know what the current is when it comes in.

[inetdog]

I get 19.5 volts open circuit. I put in one extra cell because I had room and to help overcome the Schottky diode voltage drop..
I have an amp meter on the way, I'll let you know what the current is when it comes in.

Especially when dealing with broken cell pieces, it is a very good idea to measure the current output of each "cell" before deciding to use it. You do not even have to tab it to do that in a rough way.

[Kebast]

Especially when dealing with broken cell pieces, it is a very good idea to measure the current output of each "cell" before deciding to use it. You do not even have to tab it to do that in a rough way.

True. I did check the voltage of each cell, but my amp meter died a short while ago. Hopefully all the cells are good. I know the panel produces current, I just don't know how much.

[green]

I love it. I have a few old window panels myself.

[Kebast]

Output

My ammeter came in the mail yesterday. Today is somewhat overcast, but I could take a measurement between clouds. I got 1.86 amps. The charge controller was connected, but I made the measurement at the leads coming out of the panel. Would that be considered the open circuit amperage? In any case, I was expecting something greater than 1.5 amps, so it seems the panel is producing as expected.

[inetdog]

My ammeter came in the mail yesterday. Today is somewhat overcast, but I could take a measurement between clouds. I got 1.86 amps. The charge controller was connected, but I made the measurement at the leads coming out of the panel. Would that be considered the open circuit amperage? In any case, I was expecting something greater than 1.5 amps, so it seems the panel is producing as expected.

The current must be the same at all points in a series circuit. so unless your CC is an MPPT design, acting as a DC to DC converter, the panel current will equal the battery current to the accuracy to which you can measure it.
The parameters of a panel are open circuit Voltage (Voc), short circuit current (Isc) and Maximum Power current and voltage (Vmp and Imp) based on standard light and temperature conditions. There is no such thing as open circuit current.
To measure Isc you simply connect the properly setup ammeter from the + to the - of the panel. (Do not try this while the panel is connected to the battery!!!)

[Kebast]

The current must be the same at all points in a series circuit. so unless your CC is an MPPT design, acting as a DC to DC converter, the panel current will equal the battery current to the accuracy to which you can measure it.
The parameters of a panel are open circuit Voltage (Voc), short circuit current (Isc) and Maximum Power current and voltage (Vmp and Imp) based on standard light and temperature conditions. There is no such thing as open circuit current.
To measure Isc you simply connect the properly setup ammeter from the + to the - of the panel. (Do not try this while the panel is connected to the battery!!!)

Thanks, I got the terms flip-flopped. I thought since the charge controller had a blocking diode I could measure the current from the panel before it got to the controller even with it hooked up. I'll try again later then.

[inetdog]

I thought since the charge controller had a blocking diode I could measure the current from the panel before it got to the controller even with it hooked up.

You can, as long as you trust the CC. But with the amount of current the battery can source into your meter if something goes wrong, I prefer to play it completely safe.

[Kebast]

6pm

You can, as long as you trust the CC. But with the amount of current the battery can source into your meter if something goes wrong, I prefer to play it completely safe.

Well, it gets 1.29 amps in the 6pm sun. Not sure when I'll find another sunny day at home near solar noon. I'm fairly confident the 1.8 amp reading was accurate though. Either way, I've got frames to make a few more of these

[indus]

thanks for sharing

Br

[Kebast]

Finally

Well, it gets 1.29 amps in the 6pm sun. Not sure when I'll find another sunny day at home near solar noon. I'm fairly confident the 1.8 amp reading was accurate though. Either way, I've got frames to make a few more of these

I finally got a nice bright Saturday here in Kentucky to measure the short circuit current. At 2pm EST, which should be close to solar noon here, I measured 2.04 Isc. My only problem is a bit of condensation inside the glass of the panel. I took a couple of pictures and posted below. I had to compress them quite a bit for the uploader, but hopefully they come through ok. How can I alleviate this condensation?

2013-04-20 14.09.44_edit.jpg2013-04-20 14.10.08_edit.jpg

[SunEagle]

I finally got a nice bright Saturday here in Kentucky to measure the short circuit current. At 2pm EST, which should be close to solar noon here, I measured 2.04 Isc. My only problem is a bit of condensation inside the glass of the panel. I took a couple of pictures and posted below. I had to compress them quite a bit for the uploader, but hopefully they come through ok. How can I alleviate this condensation?

[ATTACH=CONFIG]2825[/ATTACH][ATTACH=CONFIG]2826[/ATTACH]

You have just experienced one of the biggest drawback of DIY panels. If the moisture like that gets to be too much you will eventually start to short out a string of cells making the panel inoperable.

This is why some DIY decide to encapsulate their cells inside a panel. Again the problem with that is if one or more of the cells or terminations becomes bad the entire panel is trash.

These DIY are a good way to get to understand how solar panels go together and work but they tend to be more expensive then purchasing the completed item from a manufacturer with UL listing.

It is a crap shoot with your money. Sometimes it works and most times it doesn't.

If you had the ability to create a vacuum behind the glass and then seal it the moisture can't get in. That requires a pretty expensive pump and a way to apply the sealing material while the panel is in a very dry room.

[Kebast]

sealing

You have just experienced one of the biggest drawback of DIY panels. If the moisture like that gets to be too much you will eventually start to short out a string of cells making the panel inoperable.

This is why some DIY decide to encapsulate their cells inside a panel. Again the problem with that is if one or more of the cells or terminations becomes bad the entire panel is trash.

These DIY are a good way to get to understand how solar panels go together and work but they tend to be more expensive then purchasing the completed item from a manufacturer with UL listing.

It is a crap shoot with your money. Sometimes it works and most times it doesn't.

If you had the ability to create a vacuum behind the glass and then seal it the moisture can't get in. That requires a pretty expensive pump and a way to apply the sealing material while the panel is in a very dry room.

Thanks for the advice SunEagle. Luckily this panel only cost me about $18 total since I reused the frame and glass that would have just gone to the recycle bin. I left a couple of weep holes at the bottom of the panel. I think I'll sit this next to my dehumidifier for a day or so, then seal those up and see what happens. I rushed this panel a bit, and probably should have let the caulk dry another day or so before sealing it all together. I'll take more time my next try. This is just a hobby, and so far it's actually one of my less expensive hobbies .