How to test and replace diodes in solar modules

Learn how to evaluate and replace the internal bypass diodes within the junction box of a solar module.
⏱️Timestamps:
0:07 Intro
0:54 Shading impacts
1:25 Diode purpose
3:04 Safety precautions
3:36 Panel specifications
4:46 Locating the diodes
5:28 Measuring voltage
6:14 Measuring current
7:12 Diode continuity
9:22 Replacing diodes
10:25 Other videos and resources
🗎 Working on Solar Panels and Power Output (FS-2022-0646)
extension.umd.edu/resource/wo...
🌐For additional information, visit:
go.umd.edu/FarmSolar

[@davidoflight1313]

Drew, Thank you for actually showing the technique you used to open the JBox; this crucial step is omitted in many solar module stories. 🥇

[@Ben-ww1zq]

So I have 25-year-old solar panels and they don't have diodes so I think you've just cleared me in to why my system continues to test low, plus I was testing on DC which I thought was accurate and getting a low reading so thank you for pointing that information out I love how in-depth you are

[@CharlieArehart1]

Thanks so much, Drew. The first couple of minutes were really valuable, as that info on the negative impact of panel shading was not something I'd seen presented in any other videos (and I've seen many). That said, the rest of the video did veer more into EE-land, reminding me why I switched out of that degree to IT instead! :-)
But hey, for those who have the knowledge of electronics or are prepared to obtain it, it seemed to be great info. And go Terps!

[@perfectcs9759]

Thank you for this is what I need, just tested my 50w panel today as you explained it showing me 2.3A on the sun seems to me ok

[@solargoat]

Love the video… trying to figure this out and glad to see others have done this all before.

[@cronosh2o]

Great video, Thanks!

[@MrBruce0777]

Very well described

[@ImASurvivorNThriver]

Good stuff ‼️ Thanks for sharing.

[@sienervanrensburg6644]

Great video, thank you very much

[@shamanking5195]

Hi
I think the connections can get very hot
what kind of soldering wire is recommended ???

[@sairym3607]

My brand new 130w flexi solar panel shows zero amps and zero volts output, if i can access the panel connection box, when the panel has been in full sun, will i get a shock?

[@thesurvivalist.]

I have 8 solar panels with 3 diodes each, that are burned out. The junction boxes have been melted.

[@kingerz]

As clear as mud.

[@douglasheld]

8:11 The probes are in exactly the same position as in 7:36. I don't understand this.

[@maxpower9340]

Brillant, but my panels are generating 36V which is correct but only 0.4amp. This is on both when tested separately. What could be wrong? They both worked a month ago - cheers

[@winovmc]

They are failing under load. Could be the diodes in the junction box on the back of the module. If they are good, the cells could be bad. Do you have lines on any of the cells that resemble snail trails? If so, get new mods.

[@L3X369]

why not use a small diode between every cell?

[@ekstrapolatoraproksymujacy412]

You need the same size diodes in that case because it still have to be capable of dissipating the same amount of power because the same current will flow through it no matter how many cells it bypasses (cells are in series, ther is just "one" current flowing thrugh all off them). Big diode for each cell would be very expensive not just because of the cost of the diodes, but maybe more because of the complicated construction of such panel, if something cost 50% more but doesn't result in at least 50% more performance (more annual energy generation or better longevity) it shouldn't be there.

[@e9999qwe]

Wow! Messed up! He connected the probes the same way in both cases (red on LHS, black on RHS) at 7:33 and 8:07 and the connection to the meter appears to be the same (bit of red showing on the POS side) in both cases and yet he got 2 ostensibly different results on the meter in the video. How is that possible you ask? Well, it isn't. So, what gives? Well, if you go frame by frame at 7:33 you'll see that the images have been changed at some point. On one frame the meter starts to show a reading then the frames are changed (and no longer moving, tellingly) and it now shows OL. Basically, it appears he messed up and did not actually swap the probes as he should have done, or lost the footage, and they then manipulated the video to show the "correct'" answer by inserting a still image. Odd...

[@fightintheshade]

Did i miss something? You replaced two diodes with one diode?

[@roelsteenbergen-seuterschipper]

First he showed the junction box with 2 diodes with screws and then he showed another junctionbox with one diode, which was soldered

[@laryangel4082]

R

[@tittiger]

USELESS information without some links on how to procure proper replacement diodes for my sized panel!
Why bother when you only go half way?
I suspect when I need to replace them that they Internet will have been taken down also.
So no new info and no ordering of diodes when you really need them.