Help with NDB7875 Build

[mikeyjames]

Hi all,
I'm currently putting together a NDB7875 (9mm 445nm) with survival S4 host with extended copper heatsink. I'm using survival adjustable current driver I ordered at 1.8A - 2.3A.

I used a drill press to put the driver and brass ring into the pill. I decided I finally needed to get a drill press after stuffing up so many trying to do it with pliers.

Anyway, when trying to test the current I could only get it to go between 1.2A and 1.9A - this is with two fully charged 18650 Panasonics. Doesn't matter what I set the pot to it won't go higher than 1.9A.

Next thing I tested the thing with a G2 lens and it won't go past 2150mw. I know that's not to bad but DTR got 2675mw @ 1.9A

Can anyone think of what me going wrong:

A. with the driver (why can't I get to the advertised 2.3A)

B. with the diode getting 500mw less that DTR @ 1.9A

Any help greatly appreciated.

Thanks
Mick

 

[TheGreaterWatt]

My first thought is the batteries, are they capable of supplying the correct current?

The next thought I have is the driver, both driver and diode have slight variances between each item produced. So I do not find it suprising that both the diode and driver have outputs slightly under-spec, however it is slightly unlucky.

You may want to get in contact with the seller, perhaps they might have an even better idea about the products they sold you.

 

[mikeyjames]

Hi
Thanks for the info. I'm aware of the variability factor with this stuff - sometimes you're lucky and get over spec and sometimes unlucky. Just wondering if there was anything I could have done wrong as it seems really unlucky to get both a driver and a diode under spec - both at about 80% of expected output (1.9A vs stated 2.3A for driver and 2150mw vs 2675 for diode).

The batteries I'm using are these ones exactly

Any thoughts on the batteries?

Thanks
Mick

 

[DTR]

I did not see a test load in your pictures. How were you testing the driver? If you connected it directly to your DMM you may have damaged it.

 

[mikeyjames]

I did not see a test load in your pictures. How were you testing the driver? If you connected it directly to your DMM you may have damaged it.

Hi Jordan,
I tested by placing between negative terminal on battery and the case with the driver and diode semi installed in the S4 Host. I left it that way so I could easily adjust the current setting on the driver. I used the survival driver because I forgot to order a 2.4A driver from you in my last order. I had it lying around and figured 2.3A is close enough.

Anyway, is measuring current between battery and case the way i did it okay?? Pretty sure I picked up that method from this forum somewhere.

Thanks
Mick

 

[DTR]

Yea that will not damage it but with a switching driver it will not tell you the current to the diode only the current the driver is drawing which are not the same. A test load will however tell you the current out.:beer:

 

[mikeyjames]

Yea that will not damage it but with a switching driver it will not tell you the current to the diode only the current the driver is drawing which are not the same. A test load will however tell you the current out.:beer:

Thanks for the info. My lesson for today:thanks:

The thing just died Put it all together properly and took it for a spin and it lasted all of 10 seconds then something went wrong. The output looks like the remnants of a supernova - a dot in the middle with really cool psychedelic patterns extending outward from the centre. Looks great with the lights off and no lens in, but not what I was hoping for.

Any idea what may have happened? BTW, even though the output couldn't be more than 200mw (haven't bothered measuring but enough to sting the back of my hand from 20cm) it actually gets very hot very quickly.

Thanks for the help

Mick

 

[DTR]

I don't know for sure maybe something got on your lens or diode window if you say the light is like that. If you want shoot the module back to me and I can test it for you.:beer:

 

[mikeyjames]

I don't know for sure maybe something got on your lens or diode window if you say the light is like that. If you want shoot the module back to me and I can test it for you.:beer:

That would be great. Good to know if I've done something else stupid

Cheers
Mick