On Bitcoin Mining 5

It turned out that we would not be in my sister-in-law's house as long as previously thought. They were returning home and we needed to move out to a townhouse that we owned by January. This meant that I would not be able to bring the BFL Monarchs with us. For one thing they were too loud for a townhouse environment and too hot. They were also not very efficient in terms of electricity consumption. They are rated by BFL for 0.65 to 0.85 watts/GH but I measured them as using close to 1 watt per Giga hash including the power supply and the necessary laptop.

Bitmain Antminer U3 version 2

Looking for quiet, townhouse friendly miners, in October I bought two Bitmain Antminer U3 miners. This ASIC miner is very similar to the Rockminer R-box 1 (37GH/s) miners. The U3 however runs at 55 to 62 GH/s. Like the older Rockminer, the U3 is basically silent and put out little heat while using about 50 watts of power (plus wattage of attached computer). The problem is that every day or so these miners would become "zombies" meaning that they would stop working. This requires a hard reboot of the device (unplugging and re-plugging) and restarting the mining software. It's a hassle and not on a schedule of any kind so you don't know when you'll have to do it. So as quiet as this was, the fact that it had a problem like this and that I felt the hashrate was too low I kept looking for a better solution.

The better solution in my situation was the Black Arrow Prospero X-1 (X-1.5). The X-1 hashes at 100 GH/s or better and the X-1.5 hashes at 140 to 190 GH/s. This miner is unique among ASIC miners - for one thing it has a large fan which dissipates the generated heat very quietly and effectively. For another thing it has an Android-based touch screen for interfacing with the miner. The miner is also WIFI capable which means that you can place it anywhere in the house and it doesn't need an ethernet cable or a computer attached to it to run the mining software. It is truly a stand-alone device. Perfect! As it got closer to moving day (again!) I sold the two Monarchs which turned out to be pretty solid hashers - if a bit inefficient - and bought two Black Arrow Prospero X-1.5s. I also sold one Antminer U3 and kept one in the box as a backup. I ran the two Prosperos near the dining room in the townhouse for most of the winter and spring of 2016 and appreciated their silence and their heat generation. 

The nice thing about mining for Bitcoin at home is that for part of the year the heat that Bitcoin miners generate can (and is) used to heat your living space. One hundred percent of the heat generated will go into the air in your home. For instance, if my two Prosperos raised the temperature of the downstairs portion of my townhouse by two degrees Fahrenheit, then that is two degrees that didn't have to be heated by the furnace (electric blower and gas fueled) thus saving that much electricity and gas from being used to heat our home. This means that the efficiency of the miner doesn't matter very much in the winter or on cold days in the spring and fall because you are basically running a heater that is mining Bitcoin. It's another story when the hot weather comes but the efficiency of Bitcoin miners is going to be better than rated over the course of a year if they are used in environments where their heat is used. (Now if they could make Bitcoin miners that generated cold air we'd be all set for the summer!)

I'll cover my experience with Bitmain's Antminer S7 in the next On Bitcoin Mining.