445 power should be higher?

[micksterbs]

I've been working on a 445 in a 3x AAA host (pics when finished). I realise that 3x AAA is not enough to power a 445 at 1000mA with a Microboost; it starts flashing immediately. So I've tested with some freshly charged 18650's (one at a time), both protected and unprotected, and I can't raise more than about 630mW with them. But at least the laser doesn't pulse.

So I thought maybe they weren't up to it and tested with 4 x 1/2-D NiMh cells which are 1.2v nominal each and rated 4Ah... so that's 4.8v nominal, in fact they are pretty much spot on and only drop to 4.75 when the laser is at full whack. Definitely no shortage of oomph!

With this battery arrangement, the max I can get on my stonking new Kenometer USB (thanks Kenom ) is still only 630mW.

Threads like this indicate much higher power levels are attainable with just an 18650. Ok his was a Flexdrive not a Microboost, and set to 1.1A not 1A like mine, but still. 630mW? It doesn't feel right.

So I thought I'd see what the panel thought before I took my next move -- change the driver, change the diode, I guess are pretty much the only two options, no?

Oh yes... before assembling it all into the host, I didn't use a dummy load, I set the Microboost to its highest range and left the trimmer mid way round, and measured the current to the diode with a multimeter in series. I was using 3x AAA so when it started giving up at a few hundred mA, I just figured Oh poo, I'm gonna need 3x 10440 in parallel for this, ordered some, and turned the trimmer right round to max. :eg:

Ouch. Long post. Thanks for reading

 

[jayrob]

You checked the driver current with a DMM and a test load?

If both jumpers are soldered as shown in the documentation, and the pot is turned up all the way, it should be at about 1075mA's, give or take a few mA's...

 

[Giface]

I'm not sure from your post if you've verified that the diode current is 1A, with the 10440s and the pot to max. If you did, then do you have sufficient heat sinking? And if 1A only gives you 630mW from a cold start with sufficient heat sinking, then it might just be a low efficiency diode. Maybe try a different diode while keeping everything else the same.

Just my 2 cents - good luck.

Dave

 

[micksterbs]

You checked the driver current with a DMM and a test load?

I've not yet, by way of diagnosis, because it'll mean unsoldering everything. Thought I'd check if I was missing anything obvious, first. And I didn't originally because I just figured, ah well the batteries are crap, so I'll just turn it up to max, ready for the non-crap ones. Guess I just learned one of the shortcuts not to take

I'm not sure from your post if you've verified that the diode current is 1A, with the 10440s and the pot to max.

I've not, see above Also, the 10440s have not arrived yet, hence me trying with the 18650 and the 4x 1.2 NiMh half-D-cells, as they should be able to deliver the current that the 10440s will deliver (albeit not for as long).. which the 3xAAA obviously can't.

If you did, then do you have sufficient heat sinking? And if 1A only gives you 630mW from a cold start with sufficient heat sinking, then it might just be a low efficiency diode. Maybe try a different diode while keeping everything else the same.

I've not heatsunk(?!) the driver although once the batteries arrive and I do a final assembly, I will be glueing it to the back of the diode sink, which is a sodding great lump of copper :eg:

I wondered also whether there might be too much resistance in the wires for these currents, they are not exactly beefy, but I wouldn't expect such a consistent power rating if the wires were heating up or breaking down. I'll check this out though.

Thanks guys.

 

[millirad]

I'm thinking that your laser diode is good and that your driver may be improperly jumpered. The only resolution to the problem that makes sense to me, is to build a dummy load and check the current. You can use another driver, but that's the less desirable route to me. Good Luck!