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Voltage keeps dropping while testload on driver

irishluck

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I got a 2.4a driver installed in a host that is currently connected to my test load.

I know for a fact that the driver is not grounding out anywhere but maybe I have the wrong setting on the test load, I dont know.

But when my host is turned on, my meter reads 2.35, then about 5 seconds later it just slowly drops to 0.

I am using the 3A selectable test load and 2-3.7v batteries to power the host.

The jumper pin on my test load is set to use 3 diodes.
I plan on using the 9mm 445 laser diode in this host again with a 2.4a x-driver
 

oahu99

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What power source are you using?
Because if the batteries can't keep up the voltage, under the load, then eventually the regulator will stop supplying current.
So again, what batteries are you using?
 

irishluck

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What power source are you using?
Because if the batteries can't keep up the voltage, under the load, then eventually the regulator will stop supplying current.
So again, what batteries are you using?
ultrafire 16340 3.7v batteries, 2 of them, Same ones Ive used in all my lasers.
 

irishluck

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Ultrafire batteries are very low quality, and have very low discharge rate.
Get some good quality batteries and that will fix the problem.
AW IMR16340 550 mAh IMR CR123 size LiMN Rechargeable Lithium Battery
I cant see that being the problem though this time around

Im using the exact same batteries in my 1.6a, 1.8a and 2.2a laser and i put them in the 2.4a laser and the voltage drops.

If there working for the other lasers then they should work for this one too.
 

oahu99

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Ok, fair enough about the batteries.
Can you tell if the driver is getting hot?
Because that would indicate a short, or some component being problematic.

EDIT: can you take a picture of the test load setup? Or you should at least double check to make sure it is setup correctly.
The test load may be shorting, opposed to the driver.
 
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Sigurthr

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I cant see that being the problem though this time around

Im using the exact same batteries in my 1.6a, 1.8a and 2.2a laser and i put them in the 2.4a laser and the voltage drops.

If there working for the other lasers then they should work for this one too.
It doesn't work that way. Batteries have an internal resistance, above a certain current draw amount they can't supply that current without dropping in voltage. This is known as an impedance mismatch. The load is too low of impedance for the power source.

If the battery can supply 2.2A without dropping voltage but not 2.4A it means that somewhere between 2.2A and 2.4A you've found the maximum discharge rate of the battery. Just because something works at 1A doesn't mean it will work at 10A.
 
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irishluck

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I left the driver on for 1 minute with the test load.

The driver jumped up a half degree measured with a laser temp gun.

If it does mean anything, the batteries did get a little warm.
 

Cyparagon

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my meter reads 2.35, then about 5 seconds later it just slowly drops to 0.
Move your meter to the voltage input of the driver. What does that read while running?

I left the driver on for 1 minute with the test load.
You're running for 1 minute, 55 seconds of which are at zero current?
 
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irishluck

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Move your meter to the voltage input of the driver. What does that read while running?



You're running for 1 minute, 55 seconds of which are at zero current?
No, The voltage slowly drops to 0. Meaning within about a minute that 2.35 slowly drops and drops and drops until it is 0. It doesn't immediately drop to 0
 




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