Can someone give me advice on design?
1) What kind of line should I have my electrician run off my panel?
2) What PDU to get?
3) Which PSU and how many S1's per PSU and per 120v circuit?
4) What racking to get?
I don't have what could be considered a "farm" (yet) - I've got 5 S1's right now.
But here's what I did.
Originally I was running the 2 S1's I started with on 120V. I wanted to see how much they were drawing from the wall - so I ran them thru Belkin Insight monitors:
http://www.belkin.com/conserve/insight/ - I was running each S1 on it's own power supply (Corsairs).
So the Insight monitor was telling me exactly what the S1 is pulling from the wall thru the power supply. What I found was that each S1 pulls about 405 watts from the wall when it's overclocked. I started off running one of those Block Erupter cubes - that thing bounces up and down as it's hashing bounces up and down - and it's also a power pig compared to the S1. It pulls about 380 watts from the wall - for like one sixth the hash power.
Because I only had two 20amp 120V circuits where all my computer stuff is situated - and I have other equipment running - I was getting close to maxing out my available wattage (amps available) - by going up to more S1 units. So I decided to upgrade and put in a 240V drop. I put in one 30 amp 240V line with a 30amp twistlock plug. To break this out I got one of the APC "metering" PDU's off of Ebay for a really good price (it's a rack mount - what they call 'zero' U unit that is designed to mount alongside of a rack - not take up a U space).
The metering PDU has two 16amp breakers on it - and has an LCD panel that shows the amp draw for each of it's legs. So now I have an idea of how much I'm drawing on each leg and how much juice I'm pulling to support these things.
There are advantages to staying with 110V/120V - in that there are more "consumer" level electricity usage monitoring devices available for those voltages than there are for the 220V/240V stuff - at least here in the US. I think there are 240V versions of a lot of the same devices available overseas - but then you're talking about plug incompatibility issues.
My S1's seem to be consistent on that ~400W - 410W usage number when they're overclocked. So that's what I've been using to calculate how to distribute the load. I've seen people say they're drawing 500-530watts - but that's not what I've seen. I haven't run the meters across ALL of my S1's though - and I do notice that different units run at different temps. That might indicate a different wattage draw. I've been attributing it to different levels of work quality as far as how the heat sinks are applied though.
Oh yeah - and I should add that I'm going away from the Corsairs and going with using Dell 750W server supplies and the Geckoscience breakout board. Seems like a much more reliable/redundant setup and once you get the boards the supplies are replaceable for dirt cheap money. I've found I can run one S1 on one supply and keep the supply's cooling fan turned all the way down and keep it quiet. The Corsairs run hotter and I've had issues with one of them cutting off occasionally. Plus the Dell supplies just take up less rack U space than the PC type supplies do.
Hope all of this is helpful.
