Hi.
Seen maaaaany flavors, but this one is new... bypass schottky diode I removed from a solar panel. 30Volts 35Amperes. Felt like sharing :


No markings; + and - instead of kathode anode; crimpable and solderable tabs. Part number is XND38-V30C

Data at ----> https://www.alibaba.com/product-det...994.html?spm=a2700.7724857.0.0.34727cfdanYFM7

 

Appears design specifically for solar panels!
https://www.alibaba.com/product-detail/Mos-Bypass-Diode-30V-35A-PV-1600923059994.html

 

+ and - can be quite ambiguous for labelling diodes.
If you look at a bridge rectifier the two commoned cathodes are labelled +.
if you look at an LED the anode is labelled +.

 

+ and - can be quite ambiguous for labelling diodes.
If you look at a bridge rectifier the two commoned cathodes are labelled +.
if you look at an LED the anode is labelled +.

Usually when they do this it means the part is from an application specific device. In other words, the application would make it clear what to do with the part. For example, + goes to +Batt for charging. For discharging, they may label the anode with the plus sign + so that it is for discharging the battery when + is connected to +Batt.
I don't like it either

 

As I think about the markings, it certainly is a bit unclear. But at first glance it gives the impression of being obvious. And while making it a crimp-on is convenient for initial assembly, it assures that the diode is not to be re-used, nor disconnected for testing. CERTAINLY a "design for assembly used in a throw-away product.

 

As I think about the markings, it certainly is a bit unclear. But at first glance it gives the impression of being obvious. And while making it a crimp-on is convenient for initial assembly, it assures that the diode is not to be re-used, nor disconnected for testing. CERTAINLY a "design for assembly used in a throw-away product.

I would think that the reliability factor is so great that they probably don't worry about throwing anything away because it never gets to that point. Maybe once the panel gets old they just throw the whole thing out.

 

CERTAINLY, the manufacturers that use the "Design for Assembly" for their Not Worth Repairing products will not be concerned one bit!! No question about that.
The other consideration is that crimp connector. While a crimp connection made with the correct tool is usually quite adequate, not everybody has the specialized tools for every style of crimp. That may, or not, matter in every instance. Since this diode was intended as a bypass diode for a solar panel, that may not matter so very much. Maybe.

 

Given the application-specific nature of the device the ambiguity can only exist if you know too much for your own good (in this instance).

To the PV installer, is it dead obvious that you hook the + side to the + side of the source. They have no concern whether it is anode or cathode since it has only one purpose in their world.

 

To the PV installer, is it dead obvious that you hook the + side to the + side of the source.

Hi. The PV installer never even sees the diodes; are factory soldered and buried under silicone sealant in a tight box. Less install or handle or crimp or solder on it.



And installing panels in series is not 'dead obvious' as + marking is plugged to - marking and chained to the next + plugged to - and ...

 

Hi. The PV installer never even sees the diodes; are factory soldered and buried under silicone sealant in a tight box. Less install or handle or crimp or solder on it.
View attachment 353645
View attachment 353647

And installing panels in series is not 'dead obvious' as + marking is plugged to - marking and chained to the next + plugged to - and ...

View attachment 353648

That only changes the limited skill worker who will need to know + goes with red and - with black to the manufacturer’s employee. Same idea, different target.

 

That does look awfully handy for Billy Bob like me who got their panels on ebay and needs an inline proteciton diode I can crimp, heat shrink and forget about. I might have to pick some up and play with them.

 

30Volts 35Amperes

What was the V & A output rating on this panel?

 

Mike A : that diode came from a group of 24 cells (a third of a 400W panel)
Panels come in many flavors. I have 18 on my roof, are all equal 400W - 40Volt - 10 Amperes, 2m2 (40"x80¨) each.

 

... needs an inline protection diode I can crimp, heat shrink and forget about...

'Inline" diodes would be 'blocking' diodes. Perhaps the voltage for blocking diodes is greater than my 360 V Why do you think you need them to protect from what ?

 

'Inline" diodes would be 'blocking' diodes. Perhaps the voltage for blocking diodes is greater than my 360 V Why do you think you need them to protect from what ?
View attachment 353759

One reason I could think of is that if just one panel gets sunlight it will be able to output at least some power at lower voltage. In the drawing, if just the center panel gets sunlight the upper diode will conduct and the lower diode will conduct, and the blocking diode will conduct.

 

The handy part is still accurate though, despite the other part being not correct.