Does anyone think that the big mining players might be playing with their hash rates to limit difficulty growth? If the difficulty keeps growing then the energy used by the mining industry also goes up which is overall unsustainable. Eventually we should want to see a stabilization of the difficulty and the price so that BTC could be used more like a currency rather than a gold replacement. Also so that the network’s energy consumption could be optimized and eventually reduced. I think part of the reason we are seeing bans in some countries is their base energy load could be better used towards improving quality of life for their citizens instead of some non-resident miner.

I will take a crack at trying to explain.

For industrial power users they generally need three phase and it’s benefits for motors which are far simpler in design and more efficient than single phase motors. By adding the third wire there is also a good bump in available load rating without having to upsize the wire and panels feeding everything. Get three phase if you are going to have big HVAC or big ventilation fans.

150kW on single phase is around the 625A per leg range which needs some serious wire and larger gear.

150kW on three phase is closer to 425A per leg. This makes for smaller wire sizes and easier installations.

Like NotFuzzyWarm said, the line provider will do their best to balance loads as they connect services. Sure your load might tip the scales a little but in the grand scheme when a power plant puts out 400MW (1000 times the size you plan to be) your load won’t be perceived as unbalanced by the generator.

In an ideal world a mine should get 240/415V three phase but that is tough because that is a non-standard system voltage in North America.

Do the power supplies run more efficient at higher voltages? I do not believe so, at least not enough for it to really matter. Rectifiers and electronics are really efficient these days. What is nicer about 240V over 208V or 120V is that the breakers, plugs and wires to the miners can be smaller which is generally cheaper. Plus there is less chance of fire if someone accidentally brings a 18awg IEC cable into the facility. At 120V those will burn up right quick. At full 240V there is much less chance of running an individual circuit over its rated max, at least accidentally.

But profit is king. Do what is available fastest and most cost effective. You want to be running, not messing around with electrical services. 

Power is the main thing with a mine. Try to get a spot with the right power coming in already would be my advice. If the space is too large then sublet some of the space.

If you have a location that is perfect (right size, right price, good location, has security) then compromise on the power coming in. Getting up and running quickly and staying running will be paramount to ensuring profit, even with a non-ideal electrical service. Here is a possible strategy: With industrial spaces you can sometimes get multiple electrical services brought in. Start with the existing 208V 3 phase and add on or build out the larger system in parallel.

Where I am a new electrical service is tens of thousands for an industrial space with long lead times.So if the property is too big and has the right power, better to pay that extra on the purchase price of the property instead of later.

I have been considering potential setups where the hot air coming from the miners is used for heating. To achieve efficient cooling is it better to push cool air into the miners or pull hot air away?

You might be experiencing the effect of difficulty increase. The difficulty of the network has been steadily increasing the past two months because network hash rate has also been increasing. That drop in expected payouts would likely be experienced on any pool.

Lots of risks in mining and the profit can fluctuate.

Because 415/240V is a non standard supply voltage in North America you might have a hard time finding a panel with that voltage on the sticker. Just get a panel rated for either 480/277V or 600/347V with the correct current rating for your application. I suspect those panels will also ‘support’ your lower voltage setup.

If you don’t have an electrician hired yet look into it. They will save you money long term by ensuring everything is up to code and not going to start a fire. Plus they have connections to distributors that sell larger electrical equipment that is not always available to the average consumer.

If you have an electrician friend just let them get all the equipment for you. Be plain about what the end result should be, “I want 10, 30A 240V circuits with receptacles or junction boxes to connect these ten miners.” They should be able to get the right parts for you and often from a distributor with competitive pricing.

A few things with residential services. The power company won’t hook up a 200A panel to 100A service so be sure you can get 200A service before you buy a big panel board. I would also get a physically larger panel too, that way you can install the breakers with a space between them (for cooling) or have room for extra breakers for future.

Quick electrical lesson: breakers are there to protect the wire and not the load. The size of the load (your miner, approx 3000W) dictates the size of the wire (3000W/240V=12.5A, adjust for continuous running; 12.5A/0.8=15.6A so 12 gauge wire minimum) which then directs the size of breaker (12 gauge ampacity is 20A so 20A breaker).

The voltage references can seem a bit confusing. Standard system voltages in North America have some variance. Single phase residential is often 220-240V. I think it also goes back to older electrical standards. Things rated a few decades ago reference 220V or 230V a lot. Most newer standards reference 240V. Long story short is that your power at your place will be in this range, leaning closer to 240V likely. Your power company might be able to adjust your voltage up or down a bit at the transformer using winding taps if you are finding it too low (less than 220V).

Pro tip: you can avoid the cost of larger receptacles by direct splicing the miner cables to the circuit wires. Just cut off the male end, strip back the cable a bit, use a tester to find the ground and power carrying wires in the cable and splice it all in a junction box. It’s more work overall and the cables become fixed to one location but this can save a bit of money. Your electrician friend will be able to help get this right. And definitely get it right because weird things can happen if some wires are accidentally crossed.

PDU is probably not required. They can add value though if you get one with power monitoring and smart switching. If you don’t want to go with a receptacle per miner route or use junction boxes to hook the miners up a PDU is a nice prebuilt way of splitting larger power up to multiple devices. A 30A 240V PDU is only going to be able to power a couple miners though so the added cost might not be worth the benefit if you have to buy a bunch of PDUs.

Not fuzzy warm is correct. The input side of a transformer does not need a neutral, just three hot wires from different phases. On the output one side of each winding is grounded to create the neutral (wye). Your electrician will know how to hook it all up. If memory serves transformers can be field wired delta or wye at the time of installation. If you get the right voltages in/out you should be good. This is something I highly recommend getting an electrician to wire up for you.

Hello!

This adapter is probably not going to work for you. The S19 series loves 240V source voltage. This adapter will give you 120V at each cable outlet which will likely max out the current rating on the cables going to the miner.

The other thing is technically a code limitation in Canada at least… NEC is similar I believe. Plugs cannot be fed with a breaker bigger than their rating. So the 50A breaker feeding the adapter with 20A plugs would be too large. If a cable shorts plugged into the adapter it could burn up because the breaker feeding the adapter will allow a higher short circuit current.

If you want to adapt down from a 50A plug, as an electrician, I would recommend using a small sub panel with a couple 2-pole breakers feeding each miner. I know that’s a bit more work and cost but it’s a lot safer and will help keep everything safe reducing risk of fire.

What I did for my setup was run a wire from a 2-pole 20A breaker in my panel to a junction box. I cut off the male cord ends for the miner cables and entered those cables into the box. Then spliced those wiresonto the wires from the breaker. Avoids the plug code limitations and also makes the miner easier to turn on and off because both cables feeding it switch with the breaker. 

Ideally if a person could get a 240V/415V Wye setup that would be the best. Single pole breakers for each miner should be cheaper than 2-pole breakers so you get more capacity in a panel. I do not think that is a standard service size in North America though.

For a huge facility I would think the best is to go for a 347/600V wye service if it’s available. Then use step down transformers down to 120/208V for individual racks or buildings as it makes sense. More expense up front but might allow for smaller wire and breaker sizes running feeds to each subsection of the mine.

Interesting discussion! I am a ticketed electrician in Canada and have been considering how best to setup a mine from an electrical perspective.

I have seen as much at 17TH output on higher power settings (1400W) with my S9 units. I can often throttle back the power to 1100W or 1000W and still get the sticker 14TH output too, which is sweet.

Hi!

I suppose everyone and their friends are looking for mining hardware these days (same here!). I was curious to know what are some good places, sites, chat rooms, or sources for equipment. If you do not want to share I understand. Industry secrets and all that.

Locally I use Kijiji (Canadian classified ads site) for used equipment close to me. Depending on the time of year and market conditions the quality of the equipment varies.

Where do you find your equipment?

-D

I just got an email from NovaBlock that they are merging with Poolin. To quote the announcement:

"The merge with Poolin ensures the highest security for all NovaBlock clients. Now as we move forward as one of the leading mining pools, you can feel even more confident in NovaBlock. Following this change, Poolin will have 23 EH of hashrate."

I was going to try NovaBlock out later this year to see what the profit was going to be but now maybe not... I was mainly drawn to the concept of a North American pool with ownership and control centered in North America.

This seems a bit cray to me. If the owners of NovaBlock made a bunch of money I can appreciate that but pool consolidation is not what I thought they were about. Interesting times!

Any thoughts?

Thanks, that analysis matches my basic research. The estimated returns on their site also seemed low compared to other pools anyway.

Hi all,

I bought a new S19 from an online classified ad. The seller mentioned when I picked up the unit to check out greatpool.ca which he had a hand in setting up. Curious to know if anyone has run time on this pool. It seems Canadian/North American based which is interesting to me but one of the pool lists marked greatpool.ca down as a Chinese pool.

Any thoughts and opinions welcomed!

Thanks,

-D

I have not been into bitcoin for very long but watching the difficulty this past week it sure seemed like the large miners want to keep the difficulty where it is... hash rate of the network dropped as we got closer to the difficulty switch yesterday.

Hard to say what is happening overall. I figured network hash rate would be increase to match price increases but it seems like that is not happening. There are a few trends: New gears are slow to ship (Bitmain internal power struggles?). Last gen gears have a high failure rate. Read somewhere China is in the dry season so cheap hydro power might be unavailable. Also, rumors Chinese gov't interfering in some mining operations there to interrupt fraud and money laundering. Mining hash rates dropping off towards the difficulty adjustment yesterday. Maybe the system is stabilizing and trying to find a new profitable normal? Works for me!

Hi all,

I posted on the mining forum about a problem I had and it got deleted (I must be new...). Anyway, the info was helpful and relevant so I'm going to tack it on here so it can help the next person.

I was using an SD card to attempt to boot a number of used Antminer S9's that I purchased used. The unit appeared to boot but all I got was a solid red status LED light and no network. I tried booting the stock firmware from NAND and resetting the network there and then booting from SD again. No luck.

It was recommended that I add


to the uEnv.txt file. I did that and it worked! The unit was given a proper IP address and I was able to get in to the Braiins OS web interface to configure the miner.

I don't remember the poster who helped me out now, since the original post is missing... but thank you!

Thanks all! This was helpful.

I guess if I am going to be mining regular then I need to stop looking for that endorphin hit when a block gets solved and my 'reward' gets posted to my potential pay out.

First time poster, I am getting started mining with multiple ASIC machines. I have been sticking with one pool for the time being (Slushpool if you are interested) but the pool is not always lucky. This has me thinking about ways to increase my luck. One possible way to increase luck is to mine for a large pool since it is more likely they will find a block. Another way is to increase chances by mining in multiple pools at the same time, which is possible for me having multiple machines.

Is it advantageous to mine in multiple pools at the same time? Or is it generally considered better to put all your power in with one mining pool?