How Does a Bitaxe Work? Bitcoin Solo Mining Explained on 17 Watts

By Dominik Lederer, Founder, Hardware Engineer and Solo Mining Expert at Polarblocks. Network figures read from mempool.space on 12 September 2026 at 06:09 UTC. The exchange rate carries its own timestamp of 06:05 UTC.

Open an industrial Bitcoin miner and you find rows of identical ASIC chips grinding through the same task. Open a Bitaxe Gamma 601 and you find exactly one of them. The Bitaxe project describes its Gamma board as built around the BM1370, the chip used in the Antminer S21 Pro, and publishes the board files on GitHub under the CERN Open Hardware Licence.

That single chip is the whole story. Same job, same network, same rules, one seven hundred millionth of the scale. Almost everything people find confusing about home mining follows from that one sentence, so this article works through it step by step rather than starting with a promise.

Mine sits on a shelf two metres from where I write. It is audible in a silent room with the window shut and it disappears the moment anything else in the flat is running. That is a description, not a measurement: Polarblocks publishes no calibrated decibel figure for the Eco Line, and nobody should buy a device on the strength of a noise number that has not been measured. After more than a year the dashboard shows what it showed on day one, a best difficulty record and a long run of nothing. I still look at it every morning.

What is a Bitaxe Gamma 601?

The Bitaxe Gamma 601 is an open source desktop Bitcoin miner built around a single BM1370 ASIC and an ESP32-S3 controller. It runs the AxeOS firmware, joins the real Bitcoin network over ordinary home Wi-Fi, and mines to a Bitcoin address that the owner types in. No account, no contract, no custodian.

Two words in that definition carry the weight. Open source means the hardware design is published: the Bitaxe project releases the Gamma board under the CERN Open Hardware Licence, strongly reciprocal variant, so anyone can read the schematics and build one. Solo means the reward is not shared out across a pool. If the device wins a round, the whole block reward goes to the address on its own dashboard, minus the 2 percent fee that Solo CKPool charges on every block it relays. That split happens inside the coinbase transaction itself, so there is no payout system to trust and no operator wallet holding your money.

One number deserves flagging right here, because two sources disagree. Polarblocks ships the Gamma 601 factory rated at 1.3 terahash per second, and that is the figure used throughout this article. The upstream bitaxeGamma repository states about 1.2 terahash per second for the reference design. Both are defensible, the boards are tuned differently, and the gap moves the annual odds from about 1 in 13,352 to about 1 in 14,465. Anyone checking the sources will find both numbers, so here they are side by side.

Polarblocks did not invent the Bitaxe. We build editions of it in Bavaria, assemble and load test each unit, and ship it configured and ready. The design itself belongs to everyone, which is an unusual thing to be able to say about a piece of consumer hardware.

How does a Bitaxe turn 17 watts into a chance at a whole block?

It guesses. The Bitaxe Gamma 601 assembles a candidate block header, hashes it with SHA-256, and checks whether the result falls below the network target. If it does not, the device changes one number in the header and tries again, roughly 1.3 trillion times per second, every second of every day.

Across a full year that comes to about 41 quintillion attempts. It sounds like an enormous number, and against the size of the search space it is not. On 12 September 2026 the difficulty implied a network running at roughly 912 exahash per second, which puts one Bitaxe Gamma 601 at one part in 701,790,992 of the total guessing power. That fraction is the odds. There is no skill component and no strategy layer.

Daily hashrate estimates at mempool.space swing far harder than that figure suggests, between roughly 836 and 1,025 exahash per second across the three days to 12 September 2026. Those swings are randomness in block discovery rather than farms switching on and off, which is exactly why the difficulty and not the measured hashrate is the honest basis for any odds calculation.

Why does a Bitaxe that has run for years stand exactly where it started?

Nothing accumulates, because hashing has no memory. Every attempt is drawn fresh from the same distribution. A Bitaxe Gamma 601 switched on this morning has precisely the same chance in the next round as one that has run since 2024. The best difficulty figure on the dashboard records the closest near miss, not stored progress.

Solo CKPool puts this more bluntly than any product page would. Its front page states that shares there are cosmetic for feedback only, and that the service applies a minimum difficulty of 10,000. A small miner can therefore run for a long stretch before its own statistics page shows anything at all. Worth knowing before you buy: the first days can look exactly like a device that is broken.

This is the hardest idea in home mining and the reason a lottery ticket is the right comparison rather than a savings plan. Five years of running builds nothing up. It buys 262,800 independent draws, which together come to roughly 1 in 2,670. That five year figure holds only if difficulty stood still, which it will not, and the span crosses the halving expected in the first half of 2028, after which the reward drops to 1.5625 BTC. Five years of electricity at the house assumption adds another 260.61 euros on top of the purchase price.

What does the difficulty number actually do to your odds?

Difficulty sets them, directly. It is the network's self adjusting knob, retuned every 2,016 blocks so that blocks keep arriving roughly every ten minutes. Your hardware does not change when difficulty rises. Your share of the draw does. A higher difficulty means the same 17 watts buy a thinner slice of the same prize.

That ten minute target is also where the figure of 52,560 rounds a year comes from: six per hour, 24 hours, 365 days. It is a design target rather than a measurement, and blocks have been arriving somewhat faster than that lately, which is precisely why the next retarget will push difficulty up.

The retarget at block 965,664 on 5 September 2026 lifted difficulty by 1.31 percent, from 125,807,076,547,198 to 127,450,789,715,843. The annual chance for 1.3 terahash per second moved with it, from about 1 in 13,180 to about 1 in 13,352. The next retarget is projected at plus 4.37 percent for around 19 September 2026, which would leave the same device at roughly 1 in 13,936 and trim the expected value to about 14.93 euros a year. That projection is mempool.space's estimate with 1,055 blocks still to run, and it moves by fractions of a percent within a single morning.

How does a Bitaxe compare with a lottery ticket and an industrial miner?

The Bitaxe Gamma 601 sits between the two. An Antminer S21 Pro at 234 terahash per second reaches roughly 1 in 74 a year, the Bitaxe Gamma 601 roughly 1 in 13,352, and one lottery line played on both weekly draws roughly 1 in 1,344,598. The revealing column is not the odds but what each year costs to hold.

The S21 Pro draws 3,510 watts. That is about 15.3 amperes of continuous load, more than a household socket is normally meant to carry around the clock, and ASIC Miner Value lists the machine at 75 decibels. At the same tariff its electricity comes to roughly 10,762 euros a year. A single lottery line at 1.20 euros per field, played on both weekly draws, is 124.80 euros of stake per year plus a processing fee per ticket, and after the draw nothing physical remains. Set against that, the Bitaxe costs 181.12 euros in its first year, device included, and 52.12 euros in every year after it.

Criterion	Bitaxe Gamma 601	Weekly lottery ticket	Antminer S21 Pro
Winning chances per year	52,560 rounds per year, every one of them at a full block of 3.125 BTC plus transaction fees, minus the 2 percent service fee, annual odds about 1 in 13,352	104 draws per year on one line, annual jackpot odds about 1 in 1,344,598, calculated from 1 in 139,838,160 per draw	Annual odds of about 1 in 74 on a full block, reachable only under industrial power and cooling conditions
Running costs in a home setting	About 52.12 euros of electricity a year at 0.35 euros per kilowatt hour, roughly 4.34 euros a month from an ordinary wall socket, plus the one off 129 euro device, which makes 181.12 euros in the first year	124.80 euros of stake per year on one line plus a processing fee per ticket, due again in full every single year with nothing carried over	About 10,762 euros of electricity per year at 3,510 watts, roughly 15.3 amperes of continuous load, not viable in a flat
Drawer risk (boredom factor)	Low, because the best difficulty record on the dashboard visibly moves and the device is quiet enough to keep in a living room, though we publish no measured decibel figure	High, because after the draw there is no object left to look at, hold or show anyone	Very high indoors, because 75 decibels of constant noise pushes the machine into a basement or a garage
Learning effect & blockchain fascination you can touch	High, because difficulty, hashrate, retargets and the block reward become observable on your own hardware instead of staying abstract	None, because picking six numbers teaches nothing that transfers to anything else	Present, but noise, waste heat and power draw make the machine impractical to live with day to day

What does a year of running a Bitaxe cost?

About 52.12 euros of electricity. The Bitaxe Gamma 601 draws roughly 17 watts, which is 148.92 kilowatt hours across 8,760 hours, at a house assumption of 0.35 euros per kilowatt hour. At the BDEW household average of 37.0 cents the same year costs 55.10 euros, or 4.59 euros a month.

The 17 watts are a rounded figure and the cents that follow from them are arithmetic rather than measurement. Product data give a range of 15 to 19 watts, so the true band is 45.99 to 58.25 euros a year. The same caution applies to 1.3 terahash per second: at 1.2 the annual chance works out at about 1 in 14,465, at 1.4 at about 1 in 12,398.

Against those costs sits the expected value. One block on 12 September 2026 carried 3.125 BTC plus transaction fees, and at 66,585 euros per bitcoin the bare reward was worth 208,078.13 euros, exchange rate dependent and excluding the fee income. Spread across 13,352 years of expected search that is about 15.58 euros a year, or about 15.27 euros after the 2 percent fee Solo CKPool states on its own front page.

The number moves in both directions, though not symmetrically. Transaction fees push it up and are not counted here: blocks in the week to 12 September 2026 carried about 0.0195 BTC in fees on average, which adds roughly ten cents a year. The retarget projected for around 19 September 2026 pushes the expected value down by about 4.2 percent, roughly 65 cents a year. The downward effect is currently around seven times the upward one, so calling the expected value a simple floor would be too kind.

As a ratio, using the pre fee expected value of 15.58 euros, the return is 29.9 percent measured against electricity at 0.35 euros per kilowatt hour, 28.3 percent at 0.37 euros, and 8.6 percent measured against a full first year of 181.12 euros that includes the 129 euro device. Using the post fee 15.27 euros the same three figures become 29.3, 27.7 and 8.4 percent. Every one of those six numbers names its own denominator, which is the only way a percentage like this means anything.

Electricity alone would break even at about 10.46 cents per kilowatt hour before the service fee, or 10.26 cents after it. That is a statement about the power bill and nothing more. Once the purchase price is included there is no positive break even in year one at any German household tariff, and 129 euros is not recovered within a realistic service life. Anyone who wants the full arithmetic rather than the summary version will find it in our profitability breakdown.

A Bitaxe does not move closer to a block by running longer, and anyone who implies otherwise is selling a feeling rather than a machine. What the device buys is 52,560 independent draws a year for about 4.34 euros of electricity a month, and an object that keeps teaching you what the network is doing while it fails.

Dominik Lederer, Founder Polarblocks

Frequently asked questions

How does a Bitaxe find a Bitcoin block?
The Bitaxe Gamma 601 builds a candidate block header, hashes it with SHA-256 roughly 1.3 trillion times per second, and broadcasts the block if one result falls below the network target. Each attempt is independent, so no partial progress carries over from one attempt to the next.

What are the odds that a Bitaxe finds a block?
At a difficulty of 127,450,789,715,843 on 12 September 2026, a device running 1.3 terahash per second has a chance of about 1 in 13,352 of finding a block within one year. A single block round carries odds of about 1 in 701,790,992.

How much electricity does a Bitaxe Gamma 601 use?
The Bitaxe Gamma 601 draws roughly 17 watts, which is 148.92 kilowatt hours across a full year. At 0.35 euros per kilowatt hour that is about 52.12 euros per year or 4.34 euros a month, and at the BDEW average of 37.0 cents about 55.10 euros per year.

Does a Bitaxe need its own Bitcoin node?
No. The Bitaxe Gamma 601 connects to a solo mining service over the stratum protocol and mines to an address the owner enters. Solo CKPool states that its service saves you the storage and bandwidth of running a full node, and that a miner who already runs a well optimised node of their own gains nothing from the service beyond paying its fee.