Topic: My first mining project / mini-farm - page 2. (Read 2809 times)

As well as calculators to convert watts/kwatts to BTU so you have an idea of the heat load miners produce.

For me it's pretty simple, because my farms are situated in a relatively cool climate (temperatures are rarely over 30 deg here in summer) - and most of the year in the 10-20 degrees range. I just made sure that my extractor fans were capable of moving more air than the miners would exhaust. Obviously it's important to ensure adequate intake also.

For 17 / 19-series Bitmain, expect up to 500cfm of expelled air per miner (credit @philipma1957).

So if you're running 20 of the above, your exhaust fans need to be capable of moving 10,000cfm (20 x 500). You should consider also that the exhaust fans may lose efficiency over time (e.g. as dust builds up on the blades) so it would be sensible practice to allow a margin on top of this (so 10,000cfm + 15% = 11,500cfm for 20 miners).

Depending on the country, the fan capacity may be quoted differently e.g. meters per minute or meters per hour - but there are plenty of calculators and formulas online to convert into cfm.

Can you share the calculation for the airflow of the room? I'm planning to do a familiar farm.
But mine will have some swamp coolers (since my area reaches outside ambient temperature of upto 48 deg Celsius in the summer).

Hmmm, I hope you're wrong about the extension cables - I have used these in 4 small farms now without issues. The cables in this particular installation have been running constantly since April 2020. They are rated at 10A / 2300W each = 4600W per pair. Deduct 20% for constant load / safety = 3680W per pair, running 3250W load.

The Whatsminers are a different matter though, they pull up to 3700W at 240v. Initially, I installed 1.5mm cable which did overheat - but later upgraded to 2.5mm cable.

I am very impressed with your electrical supply.

Very important note for you, off-the-shelf extension cables could be very risky. I only have two GPU based miners placed in my house. These beasts takes up 1800 watt of input. I have also connected them directly to the electrical grid meter (thats what they call it in India) from where direct electricity can be drawn. I have one breaker in between.

However, over the period of time C13-C14 do not support the heating. I had incidence where my whole extension board burnt to dust. I am not sure how common is tis problem but my experience was horrible.

I have switched to heavy duty wiring now for the room where I have installed miners.

But considering your safety checks, I see myself next to zero in my set up. Lolz. 

Fans are pretty cheap, and since you have free power then you wouldn't worry much about the tiny amount of power they will consume running on higher RPM, so during summer time you might want to increase the fan-speed keep them static at say 90-100%, this is what I do to go through hot summer days, remember that you have some of the lowest quality gears (17 series) those have a very bad solder paste and high temps will eventually and easily break them, it's great to have gears of such size but the downside is that if you happen to lose a board then that's a lot of hashrate gone with the wind.



Thanks a lot for the information guys, I think I now have a better understanding about these insulation boards, I will try to source them locally.

Thank you - although it's not at home I rent some old wartime bomb bunkers (for storing professional fireworks) on a site that is now a windfarm. I am well connected with the site owners (pun not intended). They've allowed me to rent some other disused buildings on the site for hardware storage, and power is basically free but limited to the size of the supplies in the buildings - (so I can't just go putting in huge bitcoin mines)... But it works nicely for small setups like this and the site is secure.

On a VERY hot day, and just once so far, the Whatsminers threw up some error codes for PSU protection, and when you look up the error code in documentation it says "check operating temperatures" or something like that, but they never cut out and the errors just disappeared when it got cooler.

That is a very neat job mate. Takes a lot of skill and guts to put something together of that size, and at home.

Lucky you have good power costs.

What sort of temps are you getting on the miners, any problems with them stopping during heat spikes?

@ Danieleither nice work

Mikeywith here are links to boards  I  don't know sellers other then usa lowes

https://www.lowes.com/pd/Common-1-in-x-4-ft-x-8-ft-Actual-0-9375-in-x-3-875-ft-x-7-875-ft-R-Expanded-Polystyrene-Foam-Board-Insulation/3365576
https://www.alibaba.com/product-detail/5-Years-Warranty-Insulation-Foam-Board_62409612287.html
https://www.alibaba.com/product-detail/High-density-closed-cell-PIR-rigid_62526770985.html
https://www.alibaba.com/product-detail/Roof-and-wall-thermal-insulation-material_1600078186987.html

Funnily enough - yes I learned a lot from your post, but didn't fancy the idea of using MDF for the divider (glutton for punishment there) - that does sound like hard work! I saw another post elsewhere where they had used the insulation board material that I used. Also, I saw on a YouTube video (VoskCoin channel) a large commercial mining farm which also uses insulation board for this same purpose. It is literally perfect and so easy to work with. I think the original manufacturer / inventor is a company called Recticel but there are many others that manufacture it. 'Quinn' is another manufacturer. Not sure which country you are but try searching for 'Recticel insulation board' / 'Europhane board' / 'Europhane' / 'insulation board' / 'PIR board' / 'Polyisocyanurate board' (those are the search terms I'd try).


It's approx 110kw total. The wiring gets hot on a hot day, but nothing to worry about... The supply cable is XLPE which is rated for 90deg. I have a thermal thermometer gun which I use to keep an eye on everything. The supply cable has never gone above 70deg, and the individual miner cables seldom go above 55deg (rated up to 70deg). Typically the miner fan RPMS are around 2000-2400 on the antminers, and around 3000rpm on the Whatsminers - which is a good sign the airflow is excellent.

With the first set of fans I used, I found they were only effective when the air was cool-to-warm outside. On hot days, the miners increased their own fan speeds, which in turn increased the amount of airflow going into the 'hot' room. Eventually the airflow exceeded the CFM of the extractor fans, at which point everything went downhill fast. But the new extractor fans I've fitted are much higher quality with almost 60% increased CFM, which is enough to deal with every miner on full RPM (which never happens now).

Did you just copy-paste my mini-farm? that is mining plagiarism, ya like the split-room was my idea anyway.  

Such a neat set-up you got right there, very well done, I should send you some merit as soon as my bag is filled.

I wish I could find those 25mm insulation boards where I live, do they have a more common name? like a material name or something, I am stuck with MDF sheets that are hard to cut, I have to use a CNC machine to get the wholes close to perfect and it still end up a bit off.

What is the total power consumption at the moment? 90-100kw ? Make sure your 3 phases are balanced to avoid getting into troubles, also wait for a hot day to come by and test all wires' temperature to see if they are warm / hot, I became paranoid after the last incident and the new farm has over-sized wiring to avoid any unplanned fireworks.

I would like to share some images, specs and info from my first mining project. I am very pleased with how it’s turned out and how well it works – all from knowledge and advice picked up here on the Bitcointalk forum. I hope it will be useful for others planning a small setup, and / or interesting for those that share my enthusiasm for amateur Bitcoin mining. I'm now working on my 3rd project / installation, so at some point I'll upload a similar post for projects 2 and 3!

It’s a split-room design which is essentially 2 rooms, a ‘cold’ room which houses the miners / shelving / infrastructure, and a ‘hot’ room which the miners exhaust into. This helps to keep the miners cool and prevents hot air being circulated back through the miners. Air intake to the cold room is filtered to help prevent dust and moisture ingress. This design is good for equipment lifespan, but also helps with general efficiency as the miners consume less power when running cooler. This also makes for a more comfortable work environment, since the temperature is cool and the miners run relatively quiet (since the fans aren’t spinning fast).

It is currently running at 2600 TH/s (2.6PH), but will be around 3.2PH in August (when my next order of gear ‘should’ have arrived). I am currently running a combination of Whatsminer M31S+ and Antminer 17 series, however the 17 series are being upgraded to S19 Pros in a few weeks.

The setup is in a basement below ground level. Historically, the room housed a coal-fired boiler and was also used for storing coal. It has 2 x convenient coal delivery hatches which I now use for air extraction.





Initially I used 4 x 400mm / 16” fans, however I later upgraded these to larger and higher quality 450mm / 18” fans due to a miscalculation of airflow. I mounted the fans onto 18mm MDF which is strong but very easy to work with. I installed a lintel (support beam) and cut an access hatch into the brickwork (visible in 3rd photo) for maintenance access and for fitting the ‘splitter’ wall which would eventually split the construction into ‘cold’ and ‘hot’ sides. The access hatch was later sealed over with a sheet of 18mm MDF on the other side of the brickwork and screwed to seal. Frequent access is not required, so I did not bother with a door. To prevent weather ingress, I had a carpenter friend build the external wooden structure.

The following photos show general construction of the rest of the room, including entrance and cutting / fitting the filter frames, and finally the finished entrance showing the door and dust filters.





The filter frames are standard 500 x 500 HVAC filter cartridges (which I drilled so they could be screwed and sealed to the structure with silicon). The filter material comes on a huge 20m roll and is 1m wide, and approximately 20mm thick (so 1 roll is enough to cut 80 filters). I’ve found that they can be cleaned quite easily with a hoover but eventually they need replacing. I initially used 45mm thick filter material but learned, the hard way, that it was too restrictive to the airflow.

Electrical installation was basic. Supply is 3-phase 415V (3 x 240v). Voltage is excellent, around 245-246v consistently. The installation comprises a 200A Switch-fuse at source > 50mm 4-core SWA cable > 250A incomer & distribution board. Each miner has its own 20A breaker, with the power cable wired directly into the breaker. The Whatsminers draw ~3600 watts which is approximately 16A. For these I made custom power cables using 2.5mm flex and Bulgin C19 rewireable connectors. For the Antminers, I used off-the-shelf C13-C14 extension cables (1.0mm cable, rated 10A) and cut off the C14 connector, two for each miner, wired directly into one breaker. The cables run in plastic trunking to the distribution board.





The extraction fans are split into two pairs, each with their own controller. From the photos you will see that I changed the initial controllers when I upgraded the fans, as the initial controllers were not powerful enough for the uprated fans. Under normal operation the controllers are always set to full speed as this gives optimal conditions for the miners (the more airflow, the cooler the miners run) however if I’m working in the room, I will turn down the fan speed momentarily to make it easier to work. The fan controllers are not essential and in hindsight I probably wouldn’t bother fitting again.

This next photo is taken from the ‘cold’ / intake side and shows the shelving and some S17+ being installed – this is chrome catering shelving which is cheap but strong. This is also convenient for cabling as you can tie-wrap the cables directly to it:



These next photos are taken from the ‘hot’ / exhaust side. The first photo shows the exhaust fans of the Whatsminers before the splitter wall is installed. The second and third photos show the ‘splitter’ wall being installed which divides the cold and hot sides of the room. I used 25mm insulation board which is an excellent material for this application. It is sturdy and strong, but extremely light and very easy to cut. I cut holes for each miner with a small modelling / craft knife, so that both the miner fans and PSU fans are exhausting into the hot room. I made the cut-outs so there was approximately 2mm of extra space on each side, this allows some airflow over the outsides of the miner and also means the miner doesn’t have to be precisely positioned.



Finally, here is the finished room and setup, from the cold room side. You can see the insulation board wall behind the miners which divides the cold and hot sides of the room. Finally I installed a Perspex window into a section of the insulation board so you can easily see through to the hot room from the cold side (which makes it easy to check fans are operating properly, not blocked etc but without the hassle of removing the maintenance hatch).