BFL 50 and 60 cooling thoughts | Bitcointalksearch.org

lightfoot

legendary

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I fix broken miners. And make holes in teeth :-)

Quote from: helipotte on December 27, 2013, 01:08:24 PM

Running these in their original enclosures would be awesome! Sadly the run too hot like this. They would at least be stackable.

hey Lightfoot, any ideas on a custom heatsink or water cooling for these? I know water has been discussed in other threads but not recently.

Maybe just a *better* replacement heatsink. Maybe one that covers the ASICs and the mosfets. I would love to only need one big fan for a single.

Extra fans = extra power usage. I know fans use little, but as difficulty rises all is considered. I would like to keep these things relevant as long as

possible. Cheesy

Anything? Seriously I sized an Evo monster heat sink, the problem is you just need to drill and tap holes to fit the BFL board. The keys are:

1) Pull heat off the board any way you can. Oddly enough you can pull a lot of heat off the bottom, put a big-ass sink there.
2) Keep airflow on the backs of the chips for 2 reasons: It will cool the FETs and keep the stock AL sinks cooler. You know those don't completely cover the ASICs, right?

C

helipotte

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Merit: 500

Pick and place? I need more coffee.

Running these in their original enclosures would be awesome! Sadly the run too hot like this. They would at least be stackable.

hey Lightfoot, any ideas on a custom heatsink or water cooling for these? I know water has been discussed in other threads but not recently.

Maybe just a *better* replacement heatsink. Maybe one that covers the ASICs and the mosfets. I would love to only need one big fan for a single.

Extra fans = extra power usage. I know fans use little, but as difficulty rises all is considered. I would like to keep these things relevant as long as

possible. Cheesy

lightfoot

legendary

Activity: 3094

Merit: 2239

I fix broken miners. And make holes in teeth :-)

Indeed, running a side fan against those components is key. But I wonder if it's possible to keep them cool with the case together and on.

*sigh* I wish BFL had sent me one of these things back in November when I was first researching this. Could have saved a lot of time, flamage, and RMA damage. I'm beginning to think that a single heat sink on the 1850 chips would prevent everything from blowing up.

C

helipotte

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That's what the Sanyo Denki is for. It provides some crossflow above and below the board to cool the small parts/small heatsinks.

lightfoot

legendary

Activity: 3094

Merit: 2239

I fix broken miners. And make holes in teeth :-)

Quote from: helipotte on December 27, 2013, 12:17:22 AM

I've got mine open (caseless) with all stock fans in place. Two small heat sink fans reversed (pointed down), and a 120MM Sanyo Denki San ace running full speed

pointed in from the side. One of my units has heat-pipe type sinks and the other has solid sinks. They both stay in the low 60's with an external temp around 18.

Kinda noisy but in basement outa sight. Wish I could use less fans but seem to go up into the 70's without these five fans blowin on them. I make sure I keep them apart

from each other and the other miners. These seem to run hotter when in close proximity to other equipment.

Thanks. What happens when you run it with the case on?

Reason being my big flame-out with the little_singles is the 1 volt supply. On the big units the 1 volt supply is a hell of a lot better protected with sinks on the top and bottoms of the FETs yet it still blows up. Why?

My begining theory is that people take the cases off, which is bad. That messes up the cross flow that is supposed to happen. Worse, the way those sinks are mounted the 1850 chips are behind capacitor banks and some other things. Those chips are very, very critical as they are the high frequenc push/pull for the gate drives on the FETs. With more power drawn those drivers are worked harder. Heat them up too much and you blow the chip, then that locks the FETs *on* which causes them to blow up with a smoking foom.

Solution in the old days was to run something like a 2708 high current FET driver between the signal generator and the FETs to ensure they were forcing the gates down as needed. This is lower voltage stuff, but still if the 1850 overheats then that board is going to go.

Question: Can you check your FETs above the hashing chips (other side of the board from power and USB) and tell me if one little square chip is hot as hell?

C

helipotte

hero member

Activity: 650

Merit: 500

Pick and place? I need more coffee.

I've got mine open (caseless) with all stock fans in place. Two small heat sink fans reversed (pointed down), and a 120MM Sanyo Denki San ace running full speed

pointed in from the side. One of my units has heat-pipe type sinks and the other has solid sinks. They both stay in the low 60's with an external temp around 18.

Kinda noisy but in basement outa sight. Wish I could use less fans but seem to go up into the 70's without these five fans blowin on them. I make sure I keep them apart

from each other and the other miners. These seem to run hotter when in close proximity to other equipment.

lightfoot

legendary

Activity: 3094

Merit: 2239

I fix broken miners. And make holes in teeth :-)

This is going to be a thread in which I think about cooling issues on the BFL larger boards.

So I'm fiddling around with the BFL30's, and I noticed something odd in pictures about the cooling.

It looks like the aluminum heatsinks are put on the board in such a way that their fins are 90 degrees out of phase with the cooling air from the big fans. In other words the end fans don't seem to do dick.

Worse, if they're blocking the cross-flow then the 1 volt regulators are sitting in the shadows of the aluminum blocks.

So just how do the fans work, and which way is the air supposed to go? I think if one rotated a sink 90 degrees then the crossflow air would go through the fins instead of just bottling up against the end fins.

And which way do the fans on the heatsinks blow? Up or down?

C

Topic: BFL 50 and 60 cooling thoughts (Read 987 times)