killed diode

• Aug 31, 2014

• #17

PainTrane117

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DTR and djQUAN are right on the money I believe and if you are using a buck driver with only one lithium-ion cell your driver is actually not getting enough initial input voltage... so your DRIVER is under-driven (lol that does sound silly when I think about it). Slap another lithium-ion ion cell in series in there and let her rip. But like everyone said do a test load first!!! I really hope it fixes it man!

 

Last edited: Aug 31, 2014

• Aug 31, 2014

• #18

niiii

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I got those values with two batteries... and I have some 1N5402 diodes... how many diodes should I use to do test load? but without resistor?

EDIT: without resistor and 5 diodes I got 1,74A

 

Last edited: Aug 31, 2014

• Aug 31, 2014

• #19

Eudaimonium

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niiii said:

I got those values with two batteries... and I have some 1N5402 diodes... how many diodes should I use to do test load? but without resistor?

EDIT: without resistor and 5 diodes I got 1,74A

Click to expand...

No point in NOT using resistor, it's what you use to accurately measure the current.

How exactly did you measure the 1.7 Amps?

 

• Aug 31, 2014

• #20

niiii

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I used this schematic

And DMM set to measure current

 

• Aug 31, 2014

• #21

Eudaimonium

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And how exactly did you setup the whole thing? If you held up the DMM leads with your fingers or in any other way than... I dunno, soldered them in, you probably ruined the driver as well.

In other words, switching drivers should NEVER operate without a load. If your contact was broken even for a split second, I would never trust another diode to that driver.

Next time, do a proper setup. Resistors are practically free.
10x Ceramic Cement Power Resistor 5W 1 Ohm New Good Quality AG | eBay

 

• Aug 31, 2014

• #22

niiii

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I don't think the drivers broken, it keeps constant current well

 

• Aug 31, 2014

• #23

Eudaimonium

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Right... the current that killed your diode in the first place? How do you know with some sort of precise oscilloscope?

Look man, I know it's always a pain to admit, but you gotta buy some new gear.

New driver (I recommend building), new diode, and some testing and debugging gear. Like resistors.

Nobody ever said this hobby will be cheap

 

• Aug 31, 2014

• #24

DTR

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This does not look like a dead diode. It looks under powered. Has it changed since this picture?

 

• Sep 1, 2014

• #25

niiii

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no it hasnt... tried 2x 18650 batteries but its still very weak... can be the driver dammaged if it was turned on without load for about 2 secs?