SolarShed
New Member
- Joined
- Jul 20, 2021
- Messages
- 120
Hi, I wanted to do a solar panel diode test, not because I have a problem, but just because I wanted to see the health of my panels.
So I have 4x100 watt panels mounted on on a roof. The panels have the same specs, and are the same
Vmp = 18V
Imp = 5.5A
Voc = 21.85V
Short Circuit = 6.03A
but they vary in age from 1 to 4 years old.
I know the proper way to do this is to measure across each diode and then sum them up in the junction box, but its a bit of pain to remove the panels from the roof (they are not on a rack), so I basically just disconnected my panel from the fuse box and measured the two wire leads positive and negative of each of the 4 panels.
I put cardboard on the panels to block the sun, or most of it.
The good news is, when I do the test, my meter registers only on way traffic (OL) when positive on positive lead, and negative on negative leads. So when I reversed the leads, I did get some numbers, but they were slightly different,
2 were reading ~1.0 V, one was! 0.9V and one was 0.65V. At this point, I noticed that the two panels that were ~1.0 V, they were in the shade, whereas the 2 other panels, were in the sun, and the carboard over it was mostly blocking the light, but not all of it. The wires to the panels vary in length and gauge.
So, I was expecting the numbers all to be similar, but they weren't.
Just wondering if this is a sign that there could be some issue with the diodes or is it because I wasn't blocking the sun completely, or the wires leading to panels being different.
Thanks
So I have 4x100 watt panels mounted on on a roof. The panels have the same specs, and are the same
Vmp = 18V
Imp = 5.5A
Voc = 21.85V
Short Circuit = 6.03A
but they vary in age from 1 to 4 years old.
I know the proper way to do this is to measure across each diode and then sum them up in the junction box, but its a bit of pain to remove the panels from the roof (they are not on a rack), so I basically just disconnected my panel from the fuse box and measured the two wire leads positive and negative of each of the 4 panels.
I put cardboard on the panels to block the sun, or most of it.
The good news is, when I do the test, my meter registers only on way traffic (OL) when positive on positive lead, and negative on negative leads. So when I reversed the leads, I did get some numbers, but they were slightly different,
2 were reading ~1.0 V, one was! 0.9V and one was 0.65V. At this point, I noticed that the two panels that were ~1.0 V, they were in the shade, whereas the 2 other panels, were in the sun, and the carboard over it was mostly blocking the light, but not all of it. The wires to the panels vary in length and gauge.
So, I was expecting the numbers all to be similar, but they weren't.
Just wondering if this is a sign that there could be some issue with the diodes or is it because I wasn't blocking the sun completely, or the wires leading to panels being different.
Thanks