Alright got a 12x 405 and a M140 445... let's not blow them.

[DTR]

a spike in voltage would kill it easily.

And just to throw this out there you were shooting for 500mA which is the absolute top end of what I suggest on the 405's. They are not like the 445 where you can just dump 2A in them and they don't like they will just dim. The 405 is much more sensitive. If the current fluctuates even a percentage you could go way over the line with it. Also to be clear I recommend for good life to stick with 450mA on the 405's. 500mA is more of an enthusiast setting and you take some responsibility for a shorter life.:beer:

 

[Lucian]

And just to throw this out there you were shooting for 500mA which is the absolute top end of what I suggest on the 405's. They are not like the 445 where you can just dump 2A in them and they don't like they will just dim. The 405 is much more sensitive. If the current fluctuates even a percentage you could go way over the line with it. Also to be clear I recommend for good life to stick with 450mA on the 405's. 500mA is more of an enthusiast setting and you take some responsibility for a shorter life.:beer:

I'll go with 450. I was wanting to run the 445 at 1.7 or 1.8 too.

Lucian;

You can use the 24 ohm resistor to power it up.

The current will be less than 500ma,

because as Ben mentioned, the voltage will be 12-5 or 7 VDC/24 ohms.

That would be ~ 291 ma.

Just make sure all the connections are secure when you turn it on.

LarryDFW

I do appreciate the explanation of the math but I think I'll just order the pre made drivers for these 2 builds and then experiment with some DIY on a few cheaper ones I'll test driving those with my unit too to see if they hold steady and experiment with some of my throw away cheapies.

(That advice came from DTR too when I told him I had a shop around here that sold <5mw output red diodes for 1.25 a piece.... I don't even care when those break)

 

[DTR]

Yep that current should be fine on the 445 with appropriate heatsinking. If it is the diode we think it is then 1.7A is the rated current on the datasheet.:beer:

 

[Lucian]

((Seriously someone just tried to come into my apartment with me in it. I darted across the room and shouted "HEY THERE", "(Wife) CALL THE POLICE". They darted off and ran down my apartment steps, I didn't even get anything close to a description.

Bought my first shotgun last week and its still unloaded...))