List of 445nm diodes

[Grunff]

Where do you measure the current? Between battery and driver, or between driver and laser diode (NOT RECOMMENDED)?
I'm not familiar with the flexdrive, but I think the input current is NOT = the output current.

Also, remember that every diode has a different efficiency, so the correspondance of mA -> mW might not be the same for your diode.

No, I am measuring the diode current (between the Flex and the diode).

I am not too concerned about the output, I'm just curious as to why I can't put more than 1.2A through the diode.

I tried powering the Flex from my bench power supply, but that was not a happy experiment, I'm sticking to batteries

 

[anselm]

Well I hope you soldered your DMM leads in place when you did that, because any tiny
"skip" in the contact can immediately blow your driver and/or diode!

The batteries might very well be the reason for your current limit.
Li-Ions are are able to deliver much more current happily than any of the usual chemistries
employed in C-cells (Alkaline, NiCad,NiMh).

 

[DTR]

Thanks very much for that, it's really useful. I've just put together my first 445nm, using the same setup you have (A140, G1 lens, Micro Flex Drive V5). I don't have a laser power meter that goes up high enough, so I'm just measuring the current. I'm powering the Flex from 4x Alkaline C cells, and the most current I can get through the diode is 1.2A.

Is my choice of batteries likely to be the reason? I would have thought C cells would have a sufficiently low internal resistance?

Thanks this was one of my earlier tests and as you can see this was not an extremely efficient diode. It is pretty similar to most up to about 1.5A then it starts using the current less and less efficiently and ends up only peaking at 1.7W. Some of the best I have seen will peak as high as 2.1W @ 1.8A.

It is possible the range resistors on the flexdrive are not all in proper contact per the PDF. http://hacylon.case.edu/ebay/laser_diode/MicroFlexDrive_V5_manual.pdf Also I am not sure if C cells will give the proper current for this application. It is possible but I don't know for sure. I am assuming you are using three in series so you have around 4.5V?

I'm not familiar with the flexdrive, but I think the input current is NOT = the output current.

The flexdrive is a boost drive so the current draw from the batteries will be greater than the outputted current when the Vin is lower than the Vout. The best way to test this driver would be with a test load.:beer:

 

[Grunff]

Thanks this was one of my earlier tests and as you can see this was not an extremely efficient diode. It is pretty similar to most up to about 1.5A then it starts using the current less and less efficiently and ends up only peaking at 1.7W. Some of the best I have seen will peak as high as 2.1W @ 1.8A.

It is possible the range resistors on the flexdrive are not all in proper contact per the PDF. http://hacylon.case.edu/ebay/laser_diode/MicroFlexDrive_V5_manual.pdf Also I am not sure if C cells will give the proper current for this application. It is possible but I don't know for sure. I am assuming you are using three in series so you have around 4.5V?



The flexdrive is a boost drive so the current draw from the batteries will be greater than the outputted current when the Vin is lower than the Vout. The best way to test this driver would be with a test load.:beer:

I thought it might be one of the resistors initially, but I have checked them and am sure they're all soldered up.

I'm using 4x C cells in series, giving 6v with no load, dropping to around 5v under load.

Have ordered so juicy lithiums to try, and will also order another Flex drive in case there is a problem with mine.

Thanks

 

[DTR]

I thought it might be one of the resistors initially, but I have checked them and am sure they're all soldered up.

I'm using 4x C cells in series, giving 6v with no load, dropping to around 5v under load.

Have ordered so juicy lithiums to try, and will also order another Flex drive in case there is a problem with mine.

Thanks

Sounds good. Also the max input for the flexdrive is 5.5V. I know that it does say somewhere 6V but the PDF is correct and drlava has said not to exceed 5.5V or you could damage your driver.:beer:

 

[Flaminpyro]

I would be willing to bet your "C" cells are not giving you the current esp if they drop
to 5 volts when you load them, I would test to see if it isn't just one of them that is weak.

 

[jakeGT]

Iono if this is still going, but I did my first build, and have a 445 a-140 set to 1.81A (two flexes set at 901 and 910mA) outputting 1740mW with 405/445 aixiz glass lens in a SAIK host

 

[Grunff]

It was the batteries - obviously C cells have too high an internal resistance for this application. Using a single 18650 lithium gives me 1.45A. I also put a 1000uF capacitor in parallel with the flex drive. My thinking is that the fexdrive has very peaky current draw, which the battery may not be able to meet. This increased the output (to the diode) to 1.55A. All nicely heatsinked, running very nicely.

Now that I have my first 445nm, I realise that I much prefer playing with a 100mW 532nm. It feels a lot safer...

 

[rhd]

Seems like as good a place as any to ask this:

Do all of the XJ-A* projectors contain 24x diodes? For example, the XJ-A240 ?

Because it seems like most of what we see used are the 130s and 140s, but I've run into an opportunity to purchase the A240 for ~$750, and I'm tempted. Even though I have no need for 24x of them... But gosh, $31 each is pretty attractive.

 

[qumefox]

Yes. the only difference between any of the projectors, except possibly the binning of higher efficiency diodes for the brighter models, is the DLP chips. IIRC the A1x0 are 4:3 aspect ration and the A2x0's are 16:9.