Another problem..

[crazydaze]

Ok been searching for a while in the forums, no answer.
Why is my test load giving me stange readings?
Have I somehow messed my driver up?

I have this driver:
Variable Current Step-up (Boost) Laser Driver 405nm | eBay
and it will either run from a 18650 or 3 aaas in series (calibrated with 3AAAs as the starting voltage of new branded batteries can be in excess of 5volts)

Basically I hook it all up and the numbers start dancing lol, even at "0" on the pot, sometimes going higher than the 2000mV can read.

Hours of fun I assure you, sometimes I get a stable number (300~) then I lower it and it dances again!

Maybe I need a new driver.. maybe i should post a video (if anyone wants to see I can do)
Back to trying to get 3-4 stable readings in a row! :wtf:

OK quick edit:
It seems to do this on 1.5v batteries as well... but if I read it set to the 20v mark it shows me my desired voltage 0.11-0.12 (for a PHR805 that sounds good to me) on my test load and the batteries show normal voltage as well.
Shall I just set it running?

edit #2:
Ok it seems to be when my load has been running for a minute or two, could it be the resistor heating up too much, I think its a carbon film resistor 100ohm (no metal film at maplin), would that give me dodgy readings?

 

[Spyderz20x6]

Sounds like there's something wrong with your pot...
Do you have any different drivers on hand? Use one with the test load and see if you get consistent readings.

 

[crazydaze]

Sounds like there's something wrong with your pot...
Do you have any different drivers on hand? Use one with the test load and see if you get consistent readings.

It might be the multimeter tbh its not great, although I do seem to get a stable reading after I turn the test load off for a min. I did try it with a linear driver, and that got erratic as well.

 

[Spyderz20x6]

It might be the multimeter tbh its not great, although I do seem to get a stable reading after I turn the test load off for a min. I did try it with a linear driver, and that got erratic as well.

Then it's probably not your driver...
If it is a low quality multimeter, that is probably the cause. My first multimeter (some generic chinese one) did the same thing.

 

[crazydaze]

Ok.. so it gets worse... i order a couple of bits and set the driver to 100mA (new driver 405nm boost odicforce) with a phr805, the beam was feeble so i go to alter the pot, checked beam.. no improvement.. again with the pot... couple more times and i get a little worried. The kicker is the pot spins all the way round round and gives no change (i mean this thing can do a 720 degree spin and no resistance or stop) basically wtf, any advice?

Edit: Cracked it?
OK, I think I got it, on the driver the -ve for diode and -ve input are common.. so I thought I could hook the circuit to the -ve on the diode (case pin), and ignore the input in... wrong lol. As for the pot... IDC I have set it to 135~ and it is all burning well, just putting in its cree host now and "I fink it looks well sexy". Pics to come!

Couple more in my profile if anyone cares!
AGAIN, BIG thanks to everyone who posted, even if the info was only citing what the problem WASN'T!