Tnisesm 20 Pcs 20SQ050 20A 50V Schottky Blocking Diode, Rectifiers Diode,Diode Axial Kit for Solar Panel

I live off-grid in an Arched cabin that is solar powered. During the summer monsoon season, we can have some wicked lightning storms. My cabin has been hit once already. Fortunately, my solar panels were not damaged. When solar panels are hit by lightning, the most common failure is shorting of the internal Schottky blocking diodes inside the little black box on the back of the solar panel. I ordered these Tnisesm 20A, 50V Schottky diodes to keep on hand in case my panels should be damaged by a lightning strike in the future. Having spares on hand will allow me to get my solar array operational again with little down-time. I tested all 20 diodes with a transistor/diode tester. They all tested well within published tolerances.

Tested all 20 pieces with forward conduction and reverse block, as required. Forward voltage drop was between 100 and 192 millivolts when tested with diode test function on a multimeter. Germanium / Shottky type diodes usually 200mv (0.2v) or less per design. Silicon diodes are designed for a 700mv forward voltage drop when conducting. These will be used in a a12V automotive application to block reverse voltage from auxiliary circuits from back-powering existing circuits. Lighting and signaling circuits and relay control will not exceed published ratings.

Does what I needed it to do

I used these as flyback diodes for a 24V 5A DC motor I am running. They are quite large. Unfortunately, they were mislabeled. They came in a strip, with one side being held with red paper and the other side with gray. I took this to mean that the red side was voltage in and the gray side was voltage out. I assumed if the current went the other direction, then the diode would kick in and block the voltage. The reverse is true, which led to me getting extremely frustrated trying to get my simple circuit working. However, once I solved the problem it appears to work as a flyback diode with my limited testing.

I used this as a blocking diode for a power supply. It has about 350mV loss in the circuit which is acceptable for this type of diode. The problem is that with just 10A of current, this thing heats up so much that there is a risk of burning old the diode. There is no way to install a heat shrink on this type of diode. It will work fine for currents less than 1A. I paid for a 20A diode even though I only needed 10A. Having this much surplus was not enough to avoid overheating. I will probably have to search elsewhere.

I intended to use these rectifiers at 12 V with a maximum current of 5 A. My first test was the reverse current at 12 V. It tested at 22 uA, which is fine. My lab power supply is limited to 3 A, so I tested the forward voltage required to drive 3 A forward through the rectifier. It was about 1.0 V forward. So at 3 A, the power dissipation is about 3 W. At 20 amps, the power dissipation would be higher than 20 W, since the forward voltage would go higher.. In my opinion, that is why they are getting so hot. They do not seem usable at 20 A, as claimed.

Keep in mind that these items are larger than they appear in the pic.

don't buy them. useless.

Works fine

Recue hier , pour mes panneaux Echo-Worthy , diodes plus efficaces .

Used it for automotive purposes.

NOT as described, these things cook at about 5-6 amps. Buy elsewhere.