Problem with Solar Panels in series

Jakachira

Hi guys

I had/have a problem with my solar panels that are connected in series. Two panels are showing "hot spots".

I have 4 panels as follows

19.8V 7.59A (150Watts) A - showing hot spots
19.8V 7.59A (150Watts) B - showing hot spots
17.0V 5.00A (100Watts) C1
17.0V 2.90A (50Watts) C2

C1 and C2 are connected in parallel to make C.

A, B and C are connected in series.

C2 shuts down for almost a year due to a cable disconnection. So the connected panels could only show a maximum of 5A on the meter and the voltage was around 50V. I only discovered the problem when I went home this December and re-connected C2.

Do you think C2 problem might have led to these hot spots on A and B? I am afraid that I might damage my panels (A and

Thanks

BB.

Re: Problem with Solar Panels in series

Just to be clear, what are "hot spots" and what do they look like?

My guess--No, you did not damage A or B with your connection failure with C2. If anything, C1 would have been the one to be damaged (browning/blackening of cells and/or backing material, delamination of backing or metal). It is also possible that you would damage the bypass diodes (typically in the junction box) by over heating them--Especially if there was shade on the panel during the daytime.

Were these panels "good quality"? Or where they seconds/home made panels? Seconds and home made panels are more likely to fail.

Otherwise, have you tried contacting your panel mfg. yet for a warranty claim?

-Bill

Jakachira

Re: Problem with Solar Panels in series

Thanks, BB for the quick reply.

The panels (A and are SolarWorld and were manufactured in Germany. Eash one cost me $300.00

Hot spots - black and brown spots as a result of overheating. I can clearly see on the surface. The panels are free from an shades.

The panels are still producing their rated power but i am afraid if i don't pick up the problem soon they will be ruined.

The only solution i am thinking right now it to connect them all in parallel but I am afraid of voltage drop and mismatch.

BB.

Re: Problem with Solar Panels in series

If C1 and C2 are working--You should be (in theory :roll:) OK and nothing you will do can change the what is happening internal to A and B panels. Rewiring the panels should not change/reduce the chances of eventual failure.

If the panels have browning or worse--They are already in need of replacement. Should be covered under warranty (if you can get warranty replacement if your region).

One question--I have trees around my panels and I saw browning (especially along the lower edge) that looked all the world like scortched panels. Even wiping with water did not remove the browning. I used soap and water--Then staining "went away" and the panels were fine. The leaves and rainwater made a "tea" that left dark spots behind.

I had my entire 20 panel array replaced after ~6 years due to "browning' over the junction box (10 series by 2 parallel connected Grid Tied system). In my case, the browning was very light and easy to miss if you were not looking for it (looked like a light rust or coffee+milk stain just under the glass) on over 1/2 of the panels. In my case, it was a manufacturing/design defect and they were replacing a lot of panels at the time (BP Solar has since left the business). Also, in my case, I noticed the problem because my array output current dropped by ~1/2 on clear/sunny days.

-Bill