Swedish ASIC miner company kncminer.com

[Biffa]

Jebus we've had this PSU discussion at least twice before. Just buy the PSU that you want that has at least the minimum spec the manufactrer recommends. Personally I run mine off a 1500W Silverstone connected to a 2200W UPS. But that's what I just had lying around after my CM 850V died.

[1713997414]

1713997414

[1713997414]

1713997414

[1713997414]

1713997414

[1713997414]

1713997414

[1713997414]

1713997414

[Paladin69]

Yes but the initial firmware was drawing around 550 watts at the wall, so you have an entire 300 watts grace.

Fair enough.

What does this version .98.1 cause the unit to draw?

Have you measured or are you guessing? That's all I want to know.

Edit: Another point -- the large units have more capacity (pun intended) to handle "dropouts" of a part cycle. The more expensive higher capacity units also tend to have better characteristics for filtering out spikes.

[/quote]

I am drawing almost 700w with 0.981

[davewr2013]

Yes but the initial firmware was drawing around 550 watts at the wall, so you have an entire 300 watts grace.

Fair enough.

What does this version .98.1 cause the unit to draw?

Have you measured or are you guessing? That's all I want to know.

Edit: Another point -- the large units have more capacity (pun intended) to handle "dropouts" of a part cycle. The more expensive higher capacity units also tend to have better characteristics for filtering out spikes.

I am drawing almost 700w with 0.981
[/quote]

Thank you for that info.

In which case a 1000W or better power supply is a better choice. That means that 30% of the capacity is your safety factor.

My opinion is that a 100 Watt safety factor is a bit light.

Again -- your choice people you own the equipment -- not me.

[DeathAndTaxes]

700W AC is 630W DC.  Power supplies are rating on DC load.  630W load on 850W supply is <80%.

[rampalija]

haveing few 100s wats spare cant do harm ro you power price. Besacuse miner only uses how much it needs

[CYPER]

haveing few 100s wats spare cant do harm ro you power price. Besacuse miner only uses how much it needs

Really?
So then I buy 100W PSU and save electricity 

[davewr2013]

haveing few 100s wats spare cant do harm ro you power price. Besacuse miner only uses how much it needs

Really?
So then I buy 100W PSU and save electricity  

Exactly -- I did not know there were so many electrical engineers and computer designers in the crowd...  

I'm glad I did not work for any of the people wanting to cut corners.... Oh wait -- that's why I don't work as an employee now... Too any experts without the knowledge...

$85 and up for a 800 Watt supply here...
$120 and up for a 1000 Watt supply.

Cheap insurance for a $6000 machine (OK $4500 to $5000 now)...

Happy costs savings folks... Pay your money -- take your choice.

[davewr2013]

Jebus we've had this PSU discussion at least twice before. Just buy the PSU that you want that has at least the minimum spec the manufactrer recommends. Personally I run mine off a 1500W Silverstone connected to a 2200W UPS. But that's what I just had lying around after my CM 850V died.

A lot of people still come to the thread and start at the end...

Reading 100+ pages of mostly drivel would try the patience of a saint.

Edit: Aside from that -- sound advice.

Edit 2: Pardon me -- 1000+ pages of mostly drivel...

[Bogart]

There is no restrcitions on how many PSU you can use with a single miner as long as it is more than 1 

Be careful with that.  I've heard stories where ppl had that kind of configuration, and somehow turned one PS off while the other was still on.

The PS that was in the off state decided to short the +12V rail to ground, and Bad Things happened.  The magic smoke got let out of some wires and traces and other things.

[Biffa]

Jebus we've had this PSU discussion at least twice before. Just buy the PSU that you want that has at least the minimum spec the manufactrer recommends. Personally I run mine off a 1500W Silverstone connected to a 2200W UPS. But that's what I just had lying around after my CM 850V died.

A lot of people still come to the thread and start at the end...

Reading 100+ pages of mostly drivel would try the patience of a saint.

LOL

There is also a search box, pop PSU in there while in the thread and its amazing what comes back.

Of course its no issue people not wanting to read the thread, but then it goes on and on rehashing the same old arguments and the thread gets full of crap.

[davewr2013]

Jebus we've had this PSU discussion at least twice before. Just buy the PSU that you want that has at least the minimum spec the manufactrer recommends. Personally I run mine off a 1500W Silverstone connected to a 2200W UPS. But that's what I just had lying around after my CM 850V died.

A lot of people still come to the thread and start at the end...

Reading 100+ pages of mostly drivel would try the patience of a saint.

LOL

There is also a search box, pop PSU in there while in the thread and its amazing what comes back.

Of course its no issue people not wanting to read the thread, but then it goes on and on rehashing the same old arguments and the thread gets full of crap.

Well yes -- I do know about the search box....

But as for wanting to read 27 pages to direct someone to a post that is not composed mostly of predigested cattle feed is a chore in itself... Then as the firmware advances and things change material becomes out of date -- like the current power/current draw on the units.

I have followed this thread on and off since the first post -- followed the moaning and the threats.... some entertaining -- most not worth the electrons used to compose the posts. Unfortunately there is useful information that is worth gleaning -- but it's like picking fly dung out of pepper.

Almost every discussion topic in the thread has been polluted with junk -- some well meaning -- too much just pointless.

Anyway -- maybe people can clean up their act and stick to useful stuff -- but I won't bet the farm on it.

[davewr2013]

700W AC is 630W DC.  Power supplies are rating on DC load.  630W load on 850W supply is <80%.

Maybe you could take us unenlightened souls through how you come up with these numbers. Perhaps even, you could point out whether Power Factor comes into play in this calculation.

Just askin'

[jelin1984]

When the diff had go to 510

At 6 of November 2013 or at 5 November 2013

[DeathAndTaxes]

700W AC is 630W DC.  Power supplies are rating on DC load.  630W load on 850W supply is <80%.

Maybe you could take us unenlightened souls through how you come up with these numbers. Perhaps even you could point out whether Power Factor comes into play in this calculation.

Just askin'

Well measured AC Wattage will already take into account power factor.  If someone is measuring Volts and Amps it needs to be adjusted for the PF but the PF of modern switching supplies is generally pretty good (0.99).

The difference between AC Wattage and DC Wattage is simply the efficiency of the unit and for modern 80-Plus Gold PSU 90% is a good estimate (of course if you know the exact model you can look up the curve).

So 630W DC load will draw 630/0.9 = 700W AC.
The power supply converts 700W of AC electrical energy into 630W of DC electrical energy and 70W of thermal energy (heat.

Simple version is power supplies are rated by their output.  The output is always going to be lower than the input as no power supply is 100% efficient.
Output = Efficiency * Input
Input = Output / Efficiency

[Aggrophobia]

For a KNC Jupiter it could well end up drawing 750 Watts (perhaps a bit more) -- I would recommend a 1000 Watt supply as the minimum.

It would be better with a 1200 Watt capable supply. (Safety margin)

Most engineers like lots of safety margin. In this case the extra cost is cheap insurance.

You think KNC engineers have made the wrong recommendations with 850W PSU?

KNC makes this recommendation:
What specs do I need for the powersupply?
- A power supply (PSU) certified as 80+ Gold (high quality power with low variations).
- for Jupiter models, an 850 Watt PSU with a minimum of four separate PCI-E adaptors (6 pins or 6+2 pin).
- for Saturn models,a 600 Watt PSU with a minimum of two separate PCI-E adaptors (6 pins or 6+2 pins).
- for Mercury models, a 400 Watt PSU with a minimum of one PCI-E adaptor (6 pins or 6+2 pins).

However, as some pointed out the new firmware is causing some units to draw more current (power).

You pays your money -- you takes your choice.

It's your money sunk into those miners -- not mine.

I think that some have pointed out their Saturns are running close to 360-380 Watts -- a Jupiter has two more towers.

Some of us own voltmeters and know how to use them -- so our opinions may be biased by the readings.

Cheers!

Yes but the initial firmware was drawing around 550 watts at the wall, so you have an entire 300 watts grace. I've also seen those 850s comfortably pull 1000W recently, though I doubt they do so long term!

i'm sorry to correct you, but the initial firmware(0.90) was 890-910W--- 0.9V @ ~60A per VRM

[texaslabrat]

i'm sorry to correct you, but the initial firmware(0.90) was 890-910W

Exactly, which meant that 850W PSU's were put into an over-spec situation, and some of them handled it badly (eg the Corsair psu's that came back from the safety-shutdown mode and popped capacitors on the hashing boards).  Firmware all the way to .94 was pulling 900+ at the wall.

So in answer to CYPER's question...hell yes, it was a bad recommendation.  I'm glad I got a 1000W which accounted for KnC's screw-up in power estimation.  Granted, later firmware has rendered the issue moot..but for the initial release it was a swing-and-a-miss by KnC on that 850W recommendation for sure.

[seanrarey]

The only forum I am part of that can get hateful over PSU selection.  Kind of addicting, you just have to watch the carnage...

[CYPER]

So in answer to CYPER's question...hell yes, it was a bad recommendation.  I'm glad I got a 1000W which accounted for KnC's screw-up in power estimation.  Granted, later firmware has rendered the issue moot..but for the initial release it was a swing-and-a-miss by KnC on that 850W recommendation for sure.

900W AC power is within spec of V850

Even 950W AC will be within spec on 240V

[DeathAndTaxes]

Exactly, which meant that 850W PSU's were put into an over-spec situation

Nope.  Power supplies are rated on output.  At most efficiency would be 90% on the high end of the load curve.  So 900W AC *0.90 = 810W.
Overspec (>850W DC) would be > 944W AC observed (850/0.90 = 944W AC).

If the power supply was less efficient that would mean the DC load was actually LOWER.  (i.e. 900W AC observed on a 85% efficient PSU would be only 900W AC * 0.85 = 765W.

[CYPER]

Exactly, which meant that 850W PSU's were put into an over-spec situation

Nope.  Power supplies are rated on output.  At best efficiency would be 90% at high end of the curve.  So 900W/0.9 = 810W.

Overspec would be 850/0.9= 944W AC.

And I highly doubt that 850W DC is its maximum anyway.
This review has tested it up to 110% load (934.00W DC / 1032.15W AC) and efficiancy was pretty spectacular: 90.49%
http://www.techpowerup.com/reviews/CoolerMaster/V850/5.html