Question about Bypass Diodes

[JMc]

I am getting ready to mount 24V panels on my trailer and decided to check the bypass diodes in the little black box that’s located on the back. The first thing I noticed is how poorly they are soldered — I can fix that. But when I checked the actual diodes I’m seeing big differences in the forward voltage. Some are ~ 0.1V while others are reading ~ 0.6V. I’m wondering if I should replace the diodes with the higher Vf. Does a 0.5V difference matter?

 

[mike95490]

That's a problem. Most factory panels have poorly engineered bypass diodes. No heat sinking, crummy solder joints, and whatever the cheap diodes the buyer found that week.

Here;s a great read about bypass diodes & reasons ( hover over the link below, it should work, this board does not preview it well)

Active Bypass Diodes Improve Solar Panel Efficiency and Performance

The Schottky bypass diodes used in most cell-based solar panels serve as a protection mechanism that allows the panel to continue producing power when one of its cell strings is shaded or damaged.

www.digikey.ca

www.digikey.ca/en/articles/active-bypass-diodes-improve-solar-panel-efficiency-and-performance

 

[svetz]

If you're thinking about replacing them and have some partial shade, you might consider the maxim chips.

 

[JMc]

Thanks for those links and articles. I’ve used ideal diodes for isolating batteries, but since they are 3-terminal devices, integrating them into a panel J-box might be more cost and trouble than it’s worth