Mining At Home — As a Pleb

I came across this article by @econoalchemist some time in February.

It was this that really stuck with me:

“But as you’ll see, I’m not paying a premium. I’m actually getting bitcoin at a discounted rate by mining at home. This is counter-intuitive to the narratives that I assumed were true.”

Wait hold the phone, did this mans just say he’s getting discounted KYC-free sats?? It was at this moment I went down the mining rabbit hole. The rest of this post will walk you through my journey down this rabbit hole. Maybe this will inspire one of you to mine at home, maybe it will discourage you, whatever I’m doing this write up anyway.

Ok cool so mining can be profitable at home. But I need the following:

  • A miner
  • 240v outlet
  • some sort of heat exhaust system

Even if I can check off that entire list, how many sats will I be able to mine? How much will I use in electricity and how much will that cost me? Time to run the numbers.

I live in a residential home. I get residential electricity rates that won’t knock your socks off in a good or bad way. My provider offers a variable rate plan, where different hours of the day, for certain days of the week, during different seasons of the year will charge differing rates. Knowing that I would be running the miner for 24 hours a day, it made the math a bit easier. Through some complex math that would have made my 8th grade algebra teacher proud, I was able to determine the overall average cost per kwH: $0.10629

With a baseline cost of electricity, I could pop open a mining profitability calculator and start plugging in for some other variables. I liked this one. I played with variables like hashrate, power consumption, and of course the dollar price of BTC. By looking at the specs for miners that were frequently being sold in the Telegram channels I could fill in values for hashrate and power consumption. If you play with just these three values, you can convince yourself you will break even in 3 months or will HFSP for the next 2 years. It is all fun an games until you try to actually get your hands on one of these ASICs.

So over to Telegram I headed. A place I knew would be riddled with scammers and deals that were too good to be true. For some historical context, this was early March 2021, and the price of BTC was ~$50k. Everyone and their shitcoiner cousin wanted in on the mining action and the good leads were few and far between. Every listing seemed to require a high MOQ (minimum order quantity) or SOLD AS ONE LOT ONLY where the purchase totaled more than a modest citadel. As a pleb, I needed to find a MOQ of 1 with a price no higher than $6k (quite frankly I probably would have spent more since time was of the essence). I was a hawk watching these channels:

There was a lot of cross posting between the groups but there was enough new content in each everyday that I was optimistic I would find a listing that met my criteria. Eventually I stumbled upon one and reached out:

Squeaky wheel gets the grease. I won’t share the exact DMs I exchanged, but the good fellas over at @Kaboomracks got back to me swiftly to let me know MOQ was 1, price was $5400, and delivery was expected by end of April.

A contract was signed, money was sent, and I felt more alive than a Bitmex 100x yolo. Seriously I only did that so I could one day tell my grand-kids (guess how that trade ended up?).

Now for the hard part: waiting 7 weeks for delivery. Oh and figuring out how to get 240v electricity, set up a heat exhaust system, pick a mining pool, and a way to manage sound as to not piss off my roommates too much. Did I leave out the hard part of telling your nocoiner roommates you’ll be housing a new 75dB machine in the basement? Let’s start with electricity.

After weighing out the option of never using my clothes dryer again vs installing a new 240v outlet, the latter won out. My panel (while visually full) actually had an available slot that could be used to setup for a new 240v outlet. Now, I have limited electrical experience, and combined with my medium handiness abilities and armed with the knowledge of 10 DIY 240v outlet videos, I felt pretty confident I could get this done on my own. Cooler heads prevailed and I hired a professional who not only would do a better job than me, but would let me rest easy at night knowing the inevitable electrical fire wasn’t entirely my fault.

With that box checked it was time to design an enclosure for noise that would also facilitate heat exhaust. Econoalchemist goes super in depth on this in his post. Scouring the Bitcointalk forums and various YouTube videos, there seemed to be three common approaches for a noise management: beverage cooler, DIY wood box, liquid immersion. I was not going to deal with liquid immersion for a multitude of reasons, and the price of lumber was coincidentally outrageously high at the time I would be building this. Luckily, the beverage cooler market was unfazed by soaring commodity prices, and I decided to design around this.

With some cooler design inspiration I knew I would need to intake cool basement air from one side, and exhaust it out the other which would expel it outside the house. As I understood it, the cooler would not only provide noise reduction properties, but would be a foundation that would allow me to hook up the exhaust ducting. Most of the enclosure designs I saw worked pretty well to reduce noise but there was one important distinction: the avalonminer has 4 fans, not the normal 2 that you see on a S9. This would mean hooking up intake/exhaust ducting would have to be stacked on top of one another to connect to each fan OR be one giant duct that could encapsulate both fans on each side. No matter which approach I choose, the result would be either two holes drilled into each side of the cooler or one combined bigger hole on each side. The more area cut out of the cooler, the more noise that will escape.

So yeah all those old YouTube videos and guides were a bit outdated, as the newest generation of miners (excluding the Whatsminer models) all have this stacked fan design. I have yet to find an enclosure guide that addresses this generation of miners, it seems like everyone just goes with immersion, and maybe that’s because it is the only way to keep these cool and quiet. Perhaps this is the first guide on the web documenting a DIY enclosure for a dual fan ASIC model. TLDR: it worked for air flow, not for noise reduction.

Any who I got designing and determined I could use register boxes and reducers to channel the intake and exhaust air. I couldn’t find a register box to make a perfect fit over the fans and knew I would be using foil tape to make as best an airtight seal that I could. It was imperative that any exhaust (hot) air was not being sucked in by the intake fans or I would risk overheating the miner. My rough design looked like so:

To be clear I sketched this design and estimated the measurements before ordering the cooler. I took more trips to Home Depot than I care to admit to determine the register boxes and reducers available as well as to measure the length/width of each part. With this design I found a Walmart cooler that was big enough to house this.

The plan was to create this cooler housing, and have the exhaust run out a basement window, through some ducting, the air helped along by an inline duct fan, and finally expelled out a chimney. In case my diagram above and that sentence made no sense, here’s what it ended up looking like from outside.

With the enclosure built I installed the “wood window” with the 6" hole for the exhaust.

I built the rack, had to stand it on bunk bed risers to get the enclosure to the proper height, and was ready to put it into place. This thing was pretty heavy to move alone, and an expensive mistake if I dropped it, but this was a YOLO operation not a professional setup.

I then decided it was a good idea to help with airflow. The in line duct fan pictured there actually was less effective than using that fan pictured in the bottom left of the photo. I currently use that fan pointed right into the intake cooler hole, supported by the white box fan bringing fresh air into the room. Note that the power and ethernet cables are coming in through the intake hole.

7 weeks, 2 legacy bank payments, 6900 telegram messages read, 12 home depot trips, and 2 electrician install sessions later and I was actually up and running.

Sweet dude, your janky setup looks like it will fall over when little red riding hood’s wolf blows it over. That may be true. But it is also true that this setup is yielding me ~45,000 sats per day. I have been running with no issues for about 7 weeks. Yes at some point I will have to shut down and do some dust maintenance.

All in for ~$6271. Could I have saved money by immersion cooling? Maybe. Did the cooler help with noise? Almost not at all. I installed a door to my basement which did wonders. I’m stackin sats everyday and really that was the goal here: KYC-free cheaper-than-market-price-sats. I won’t go into pool details or my exact projected rate of return here. Econoalchemist does a much better job explaining this stuff, I just wanted to document the process here from a pleb perspective. If number go up, my time to break even goes down. As long as price stays above ~20k, I mine profitably. Don’t believe any home mining FUD until you run the numbers yourself.

Run 👏 the 👏 numbers 👏

Big thank you to the following folks who helped me along the way, whether they know they did or not: @econoalchemist @nickfost_ @kaboomracks @brettinthewoods @vicariousdrama the people on Bitcointalk, and my roommates for allowing this to happen.

Please reach out with any questions here or on twitter @bitcoincoderbob

Note: a keen eye may have noticed the miner I purchased (a1246) is not what I received (1166 pro). There was some Canaan manufacturer tom foolery that went down, but you take what you can get in a market where miners are scarce. I am entitled to a $540 refund from Canaan if it ever comes in.

Edit:

Wanted to add a bit about the power cable for the miner. What was not clear to me was when you buy a miner, it does not come with a power cable. My best guess is that since these miners are going to be shipped all over the world, the manufacturers cannot possibly know what type of outlet they will be plugged into, and thus it is easier and cheaper for them to just ship without one. My unit has a C20 connector and so I needed the corresponding C19 plug. The C19 (it is the female fitting for the C20) needed to be one end of the plug, and the other side needed to connect to a 240v outlet. The NEMA L6–20 is a common plug for 240v and could handle this load (3400W, -5%~+8% according to the manufacturer website). So I went ahead and bought this cable. At the length of cable (6 ft.) the cable has not gotten hot to the touch.

Edit 2:

I in fact am NOT the first person to design an enclosure for a dual fan ASIC. Check out the awesome write up by @Diverter_NoKYC. In the write up, the enclosure uses these duct shrouds which is exactly what I should have used in place of the register boxes. Really wish I saw this write up before I built.