Bitcoin Forum

Hi All,
I set up 153 13Th/s  S9s just over 10 days ago and I am trying to optimize earnings/profit. The machines are on track to get over 45btc first month.  I do not need to cash earnings right away or near term.
I am getting Bitmain's power rate since it was prepaid for 6 months. (not going to mention the actual $ amount per kW not to start another topic)
Please advise on what percentage to sell and when given the current environment. I know it is not a simple question with too many parameters in play like difficulty/hash rate and btc price.
In other words how would you do it based on previous experience?

 You used Hashnest or you took delivery of 153 S9s?

Depends on how much risk you want to take and how much you believe in bitcoin. If you think the price will go up, you should hold more. If I were to have a farm that large I wouldn't take too much risk and sell basically all BTC I mined.

I am trying to figure out a formula that will work with different scenarios
btc stable up or down.

I would sell 25% of all the mined coins and hold for another few years the remaining 75% of them. Of course this is the most ideal scenario if you firmly believe in a bright future for bitcoin (I do personally). If you are not a believer and only want to see your cash increase then sell all of them , but I don't recommend doing such thing. In the end the final choice is yours, use this thread to collect different opinions and decide yourself after you have valued every thing.

 The formula is not that complicated.  Here's a list of variables in the equation for your profit:

• Bitcoin value
• Bitcoin difficulty

Everything else is fixed.

• Electricity cost

 Of course you are purposely being vague about the details of your deal which is the thing that actually sets you apart from other miners.
Let's look at this in terms of 14 day periods (about the same amount of time as a difficulty retarget period)

Fixed

B_i = number of Bitcoins mined per initial period (22.04 - trust me...)
t = number of hours per period (336 - trust me 'cause I'm not showing all the math)
P = power required (according to Bitmain Specs 194.922 kW) for 153 S9s
c = Cost of electricity  per kWh (you know it but wont say)
d_i = Initital Difficulty (317,688,400,354)
f_p = power factor (efficiency of power supplies)
C= P*t*c/f_p total power cost for one period (this is actually fixed but you haven't told us the value for c)

Variable

V_c = current value of Bitcoin
d_c = Current Difficulty

---

  When B_i*V_c*(d_i/d_c)-C → 0; shut down the miners

That's the simplest math.  If you want a more detailed analysis - you'll have to pay.

Great Answer! ----^

I don't see "t" in the equation.  This is interesting to consider a larger farm. What is bitmain's power rate? 

I'm totally new and this is not a "newbie question" but certainly helps a newbie see potential.

Nevermind. I see it.

 Thank you!  While looking to find the t, I realized that I forgot to use the power factor!
My post has been edited to include that constant.

What you are asking is no different then asking where the stock market will be next year.

We can't predict the difficulty or price for BTC.

Thanks. I understand the math and there are calculators that take difficulty and btc price into the consideration.
I was rather asking based on your experience, what would you do? I am not trying to time market. I do believe in BTC otherwise I would no consider such investment in the first place, but as any investment it is only investment while you make profit. Based on current difficulty and price levels bitcoin mining is not profitable much with electricity rate of 0.02c per KW.
I was thinking of storing all until price goes to 2000$ if it does sell 20% then if doubles again depending in how long sell more.

With 0.02/kwh its very profitable mining anything. I think you mean 0.07 per KW with an Antminer S9.

We don't know where the price will lead. We all want it to go up but there are no gaurantees. Do your own due diligence and don't take advice from a web forum since none of us are financial advisors.

so you invested about 200,000 usd  and you have zero power cost for 6 months.

on hash nest right now  s9 maintenance  fee is 27,51%

I suggest you match that. i.e. today sell 27.51% of all coins earned

if maintenance goes to 40%  match
 if it drops to 20% match
do this every one of the 180 days your power is paid for.

you will make 180 sales of coins

  then recalculate what to do.

https://www.hashnest.com
is complete rip off
0.075$ per kW
according to http://jblevins.org/btcmpc/ with bitcoin difficulty increasing 4% every 14 days  (historical average even higher) and BTC say $1200
you will not make money from day one not to say in 2-3 months

I would not even consider rate above 4c per KW. But I am getting much less