Bitcoin Forum

Hello, Y'all!

I really hope this is the right place to post if not, sorry mods for making you do more work.

Anyway, the title pretty much explains what I'm going for here. I've been thinking about starting mining for a while; but, I decided to wait until college to save on electricity. All utilities come with the dorms, so it will help keep the profitability up. So here's my thinking so far.

I'm going with the Antminer S9. It's the most powerful and most efficient for the money. I don't think there will be too many arguments there. With that, I was planning on getting the Bitman APW3++. Seems to be sold with the S9 a lot, so I'm assuming it works well with it.

Here is where my first issue is, the outlets on campus are your standard household 110v, which, if I'm understanding correctly, the APW3++ can run on; however, it can only supply 1200W, while the S9 requires 1323W +- 10%, so for the sake of argument lets say 1450W.

So here's question 1, if I was to run the APW3++ off 110v, and it produced 1200W (i.e. best case), would the S9 still run, albeit at a lower speed, or, would it not run at all? Even if it would run, I've seen many places suggest using 220v power anyway. So outside of rewiring my entire dorm, would there be any way of converting 110v to 220v? I've seen online voltage converters but, I want to know if anyone had ever used these to mine BTC and what their results were.

Outside of that, my other concerns were connecting to the internet. What is the process of connecting an S9 to the internet, and would connecting to WiFi be an issue (if that's even an option)? Beyond that, my plan was simply to join a pool and start working.

Any answer I can get to these questions, or any comments or criticisms of this plan is greatly appreciated. Also if anyone else has mined while in college, I would love to hear about your experience.

You might be able to run 2 of the hash board, but it is unlikely to run all 3 (although there are rare reports of people running on 110V).

Its not a matter of voltage, its a matter of current.  Changing your voltage is not going to change the amps you draw out of the dorm room electrical outlet.

You could get a wifi to ethernet adapter, but wifi latencies may fool with your mining results.

What you didn't mention considering:

1)  The noise - An S9 sounds like a vacuum cleaner running full out (and an old noisy one at that)
2)  The heat - watts in = heat out.  So you will be running the equivalent of a space heater full time in your dorm room
3)  Fire hazard - most colleges consider miner fire hazards, since students due stupid things like throw blankets over them during room inspections
4)  Illegal use of school resources.  Anything provided by most colleges used for private profit is generally good for getting kicked out

Bitmain no longer owns the "Most efficient' title, although they still use it.  They are however, the cheapest/TH.

Ok so I just want to run through this and make sure I have the correct understanding of everything you're saying.

So on 110v, I would be able to run 2 out of the 3 boards, meaning the speed would be apx. 2/3 of max speed.

So my thinking behind steeping it up to 220v is that the APW3++ has a maximum output of 1600W at 220v, which would allow me to run all three boards and have the maximum speed.

So outside of connecting to WiFi, what would my options be?

I have heard noise can become an issue. Have not come up with a solid plan other the to suck it up and deal with it.

Since it really doesn't cost me anything, I'm simply gonna crank the AC all the way down. Should keep it nice and frosty.

Combining 3 and 4 here, I can't find anything stating I'm not allowed to have one, nor anything saying I can't make a profit on campus; however, both of these require more research on my end.

I appreciate your input. Thank you very much.

Yesss, but...
A. Drawing the 1,300-1,400w 24x7 from a standard 15A outlet is pushing it and the wiring feed it hard. You will be pulling about 12.7A from the 110v socket and it WILL get rather warm.
b. the cheap voltage converter transformers such as you see from 220-electronics.com are crap. Tried 2 'rated for 2kVa' ones and on a s9 load they both literally fried in just over a month. Industrial-rated ones are fine but also several hundred $ for a 2kVa one.

so you are in a dorm with free power and you are buying a really loud unit.

get your self an avalon 841  set it to a lower speed.  it will run quietly  and pull under 1200 watts

read this review

https://bitcointalk.org/index.php?topic=3375954.0

these are good sellers.

https://www.blokforge.com/

and you get a longer warranty.

you are much better off with this unit.

mostly as it is easy to get it to run at a lower fan speed.

it costs more but the warranty is much much much better.

Research school's residence hall rules, Internet use, and other policies before investing. Not worth ruining your future. Every school I ever went to did not allow commercial use of Internet and those policies were in place well before Bitcoin existed. Most colleges have a list of approved appliances and many won't allow you to install portable heaters, AC units, or anything that can produce enough heat to start a fire due to fire hazards and electric use.

And your missing the point on APW3++s: at 1450Watts, you would be pulling 13.2 amps at 110V on wiring system rated for a continuous load of 12 amps (80% of a 15 amp breaker).  And that is before the inefficiency of the step-up-transformer is factored in.

I'll also second the suggestion for an 841 or even a cheaper 821 (slower, but less power as well).  My 821s do about 11.5 TH/sec.

Of course, NOTHING else can be running on whatever circuit your putting these on or you will be popping breakers.

I think the biggest mistake people who say "I have free power" make when referring to their dorm room is that while yes, you might not have to pay an electric bill, your usage is still monitored. So when one room's usage goes up 150% the college will take notice and pay you a visit.

I will point out one thing that has nothing to do with the unit or the power.

Consider that it would only take 1 complaint from your roomate, and you will have to shut down the equipment.

I remember reading a post last year sometime in October and a student was forced to sell off their gear because of a complaint. You may want to consider waiting until you get the lay of the land; maybe you can talk your roomate into joining you on the venture.

I agree with the others an undervolted 841 is a better option.


Unless he violates the rules there is no issue. He also wouldn't be "scamming" the university, just breaking rules regarding appliances.