Flickering 445 build

[bbshamsa]

Hi all.

I've got a problem I'm hoping some of the more experienced builders might be able to help with.

My first dual driver (flexdrives) build ~2w, estimated, starts to flicker after around a minute of being run.

When I say "flicker" it's not high frequency, more like on and off quickly once it gets hot.

The build's as follows:

- 26650 Ehgemus host
- Dual heat-sunk flexdrives set at 900ma each... Not thermal epoxied to the host body, yet.
- Each has a small ally block thermal epoxied to it.
- A140 diode

Before I try and see if epoxying to the host fixes the problem, and not being able to turn back if it doesn't, I thought to post here and see if I need to drop the current a bit.

Could something as simple as fixing to the host body, to be more specific the pill body, fix this?

Any help is appreciated.

Thanks.

 

[Benm]

This does sound like a heatsinking issue, with the driver cutting out when it gets too hot and turning back on again. If there is no heatsink at all that may happen pretty quickly, as fast as several times a second.

You can test this by feeling the chips temperature. You cold also temporarely fix a small heatsink to the chip using thermal grease or something removable like that to see if that fixes the problem or at least slows down the rate of flickering.

 

[Blord]

You need the flexdrives also heatsinked to the host. Just a small block attach to the flexdrive wouldn't do any good, the heat must be dumped to the host.

 

[Fiddy]

Heat-sink the drivers to the pill area, like what i did with my ehgemus 32650 custom:

You don't have to use copper heatsink, chunks of aluminum will work well also.

Ive also got some arctic silver thermal paste around the diode too and after 40 seconds it drops from 2240mW to 2200mW

 

[JaiNobeZ]

Ehh, I'm with Benm. Experiment a little before making an irreversible change.

 

[Benm]

Indeed - i'm pretty sure its a thermal issue, but it would be rather bad if you potted the components in place with thermal epoxy and then found out the problem was elsewhere.

 

[bbshamsa]

Many thanks guys.

I'll try clamping the heat-sunk drivers to the pill casing with a little thermal paste before permanently fixing them.