Bitcoin lottery mining, explained properly

Bitcoin miners compete to find a number that produces a hash below a target. Whoever finds one first publishes the block and takes the whole reward — currently 3.125 BTC plus transaction fees. There is no second prize and no partial credit.

Industrial mining farms smooth this out by joining pools: thousands of machines combine hashrate, and the pool pays each participant a proportional share whether or not their specific machine found the block. It turns a lottery into a wage.

Lottery mining is the deliberate refusal to do that. You point a small device at a solo pool — or at your own node — and keep the entire block if you win. The expected value is the same as pooling. The distribution is wildly different: almost certainly nothing, with a tiny chance of a life-changing amount.

The devices are small: a Bitaxe Gamma 602 is about the size of a paperback and draws less power than a lightbulb. That is the appeal — the ticket costs a few euros a month in electricity, and it never expires.

The maths is not complicated. Expected hashes per block is difficulty × 2³². Divide by your hashrate and you get the average time between your blocks.

For a 1.2 TH/s Bitaxe against a network difficulty in the hundred-trillions, that average lands in the range of tens of thousands of years. Not a typo. The calculator computes it live against the current difficulty for any device on the site.

Two things stop that being the whole story. First, it is an average of a memoryless process — a block has the same tiny chance of arriving tomorrow as in year 9,000. People genuinely do win: small solo miners have found blocks, and a handful of Bitaxe-class devices have hit in the last couple of years.

Second, the ticket is cheap and reusable. Spending a few euros a month on electricity for a permanent, non-expiring shot at several hundred thousand euros is a defensible way to spend that money — as long as you understand that is what you are doing.

Work through four questions in order:

1. 1
   What is your budget, all in?

   Add a year of electricity to the sticker price. A cheap, inefficient miner often costs more in year one than a pricier efficient one. The year-one column in the comparison table does this for you.

2. 2
   Where will it live?

   A single-chip Bitaxe at 35 dB is fine on a desk. A NerdOCTAXE at 52 dB is not a bedroom device. An Antminer S9 at 76 dB needs a garage. Noise eliminates more options than price does.

3. 3
   Do you want a project or an appliance?

   Open-source boards (Bitaxe, NerdQAxe) give you AxeOS, full tuning control and a large community, but you assemble the power supply and cooling story yourself. Closed appliances (Avalon Nano, Apollo) arrive working, with a warranty and an app.

4. 4
   Does the heat help you?

   Every watt becomes heat. A 140W Avalon Nano 3S in a home office in winter is a space heater you were going to run anyway, which changes the economics completely. The same device in July in a warm climate is a nuisance you also pay to cool.

Joules per terahash is watts divided by TH/s. It is the exchange rate between electricity and lottery tickets, and it is the number that separates good hardware from bad.

Two devices with the same hashrate but 15 versus 30 J/TH give you identical odds — and one costs twice as much to run, forever. Over five years that difference dwarfs any plausible saving on the purchase price.

One caveat: efficiency figures are usually quoted at stock settings. Overclocking almost always makes J/TH worse — you buy hashrate with disproportionately more power. Our comparison table lists both stock and tuned figures where the community has measured them.

Noise. Small fans at high RPM produce a whine that is more annoying than its decibel rating suggests. Many owners swap the stock fan or undervolt slightly to keep it liveable.

Heat. Wattage in equals heat out, exactly. An 18W Bitaxe is unnoticeable. A 200W device will measurably warm a small room. A 1.7kW Avalon Q is a full-sized electric heater and needs to be planned for.

Uptime. Wi-Fi-only devices drop off networks. Since your odds are proportional to time spent hashing, an unnoticed week of downtime is a week of tickets you paid for and did not get. Set up monitoring.

Power supplies. The cheap brick that came with your miner is the most likely component to fail. Boards that run on standard USB-C PD are easier to keep alive because you can use any decent laptop charger.

1. 1
   Power it up and join its Wi-Fi

   Open-source boards broadcast a setup access point on first boot. Connect, then point it at your home network.

2. 2
   Choose a solo pool

   Solo pools such as ckpool's solo service or public solo endpoints handle block templates and pay the finder the whole block minus a small fee. You supply a Bitcoin address as your username — that is where the block would be paid.

3. 3
   Use an address you control

   Not an exchange deposit address. If you win, the payout is a coinbase transaction, and you want it landing in a wallet whose keys are yours.

4. 4
   Set the frequency and voltage conservatively

   Stock settings first. Confirm it is stable for a few days before tuning. Chasing the last 10% of hashrate is how boards die.

5. 5
   Check it occasionally, then forget it

   That is the whole point. It hashes away, costs a few euros a month, and one day it either does something extraordinary or it does not.