BB750 heatsinking?

[Chief_Wiggum]

Hi all,

I have a BB750 that'll be driving a 5W LS using 2 CR123s. I've read in some threads that the BB700 requires some heatsinking. I wondering what components need the heatsink and how I should go about doing it. Thanks for the info.

 

[dat2zip]

The BB700/750 configuration taxes the IC and the diode on the board very hard. Those are the two black things on the board. It's too difficult to probably attach little heatsinks to these parts so most people tend to pot the board in thermal epoxy to the flashlight housing or to something that will conduct the heat to the outside.

I have on the bench been able to keep the converter board happy with a small fan blowing on it. The board needs to be able to dissipate a little over 1W of power and not get hot. You can use Arctic Alumina epoxy as probably the 1st choice and thermal RTV as a second alternative.

Wayne

 

[Chief_Wiggum]

Thanks for the quick response, Wayne. I think I'll pot it in some AA.

 

[tylerdurden]

So arctic alumina is non-conductive? I don't have to worry about gooping it on and shorting any traces?

Where can I get a good thermal RTV? The only thing I was able to find on the web was a big industrial sized tub.

Wayne, maybe you could stock some RTV in the shoppe.

 

[Chief_Wiggum]

Well, I just potted mine, so we'll see if Arctic's claim of non-conductivity is true /ubbthreads/images/graemlins/smile.gif

 

[Rothrandir]

yes wayne, if you could sell alumina and silver i would be greatly appreciative /ubbthreads/images/graemlins/wink.gif

 

[Y2Kirk1028]

I use Dow Corning 748 non-corrosive RTV Sealant, but I don't know if it's good at thermal conductivity.

 

[tvodrd]

Sometimes I lack self restraint:

Actually, you can hacksaw/file a small piece of a copper penny or aluminum to sit on the IC and diode. All I've seen have been within a couple of thou in height. The guy above is now a .200 "sandwich." The hole for the (-) header pin is very small where it exits to permit staking around it for LS/module ground.

Larry

 

[McGizmo]

LOL,

Larry you *are* a sick puppy. /ubbthreads/images/graemlins/grin.gif Nice job!

- Don

 

[dat2zip]

Larry,

I'd like to order 200. /ubbthreads/images/graemlins/smile.gif Thanks...

Wayne

 

[Rothrandir]

larry....i hate you! /ubbthreads/images/graemlins/tongue.gif

that's amazing! /ubbthreads/images/graemlins/drool.gif

 

[tvodrd]

/ubbthreads/images/graemlins/blush.gif

Larry

 

[LukeK]

Take a hacksaw to a penny? Are you encouraging us to engage in illegal activity? *tsk* Shameful Larry, just shameful.

Seriously though -- that's one heck of a heatsink. Awesome job.

 

[pjenkins00]

/ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/bowdown.gif /ubbthreads/images/graemlins/bowdown.gif

Yowza!