Driver Test

[imraneesa]

Hello everybody,

I have buck driver of 1.8a, it gives 1.8a constant current. I tried to test it. I have ac to dc adaptor of varying voltage. I set it to 7.5V but when I check with Multimeter it was showing 13Volts. anyways I took the 7.5V for calculation because the adaptor shows that value. I calculated using ohms law.
V=IR
R=V/I, 7.5/1.8
R= 4.166 say 4ohms
I have 1 ohm resister (don't know how much wattage) on checking with multimeter I got the value around 1.5 and then I connected alligator wires and then checked it and it gave me 4ohms resistance.
then I connected the AC-DC adaptor to the Driver and I connected multimeter in series with the output of the driver to calculate current.
It suppose to show me current around 1.8A but I only get 700mA.

I read some threads saying to test with 1N4007 diodes and I did that also I took 4 1N4007 Diodes and connected them in series and then tested the current and I only got 500mA.

I also tried it with two 18650 batteries but current only showing below 700mA.

I want to know what is the mistake and where will be the fault. Am I doing anything wrong. is that Adaptor wrong? Please clarify. :cryyy:

 

[DTR]

Yea you will need a test load to test a switching driver like a buck laser driver.
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Which driver are you using?

It looks like your adapter was giving more than 7.5V as what you were reading on the DMM for voltage is just the full passed voltage minus driver dropout. Reading output voltage does not really show you anything. It is also possible the driver has been damaged from running without a load when had it connected to just your DMM. I would definitely check it again with a test load and make sure it has not been damaged before connecting it to a diode.:beer:

 

[Cyparagon]

Tell us more about the power supply you're using. You're not using one of these things are you?

Their power is too low. And it sounds like yours might have a shorted pass transistor somewhere.

 

[imraneesa]

ya first I used two 18650 batteries. and then I tried one of those type adaptors. with both I am only getting 600mA.

 

[Cyparagon]

What driver are you using?

Stick to the 18650s if you don't have an adequate power supply. What is the voltage input to the driver (under load), and what is the voltage output of the driver (under load)?

 

[imraneesa]

I am using x-drive. 1.8a driver. and gtl 2300mah 16340 batteries two numbers.

 

[Cyparagon]

You keep half-answering people. Please answer all questions.

What is the voltage input to the driver (under load), and what is the voltage output of the driver (under load)?

 

[DTR]

I am using x-drive. 1.8a driver. and gtl 2300mah 16340 batteries two numbers.

I would start by ditching those 16340 cells. If a seller is claiming 2300mAh capacity in a 16340 then that cell is one to avoid buying as it is not possible and at best the cell will way under perform at worst the cell could be dangerous. Best to stick with quality brands.

If this is the same battery you have in this review on those cells they were found to have 1/7th the claimed capacity and could not handle discharging at higher currents.
Test/Review of GTL LS16340 2300mAh (Gray) | BudgetLightForum.com

If you need quality 16340's best to use these.
AW IMR16340 550 mAh IMR CR123 size LiMN Rechargeable Lithium Battery
And if your host can fit an 18650 you can probably fit two of these.
AW IMR 18350 800mAh LiMN Rechargeable Lithium Battery

Both quality cells and can handle the current demands of the driver.

 

[imraneesa]

Sorry for my half answers Mr.Cyparogan. i checked with fully charged batteries and the value showed as 1.4A. so i understood that the issue is batteries. i will soon buy psu to check the drivers. thank you for all the support.