I came home with magic beans

In 2020 I installed a 6.3 kW solar panel system on my house. It’s been pretty great. 2020 being the Plague Year that saw my home state thrown into prolonged periods of stay-home restrictions in an effort to reduce the spread of Covid-19. It was a good year to have solar panels - I spent almost all of 2020 in my house.

In the two summer months we’ve just had - we ended up in credit with our retailer despite our distributor being less than stellar when the customer decides to use renewable energy.

I noticed the amount of excess power generation from the solar system yielded some pretty paltry returns. My retailer pays me $0.1020 for every kWh (kilo-watt-hour) that my system feeds back in to the grid. They happily charge me $0.3245 for every kWh that I take off the grid.

I want my solar system to not just pay for itself, but also make money. That won’t happen for a long time when I give my energy to the distributor, that game was rigged from the start.

With that in mind, I decided to secure my financial freedom with the speculative valuable MAGIC BEANS! (Bitcoin)

I’m going to contribute to a mining pool while the sun is up (for free) and get rewarded in Bitcoin. Then: I don’t know, maybe hold on to these magic beans or sell them or something.

What did I have a week ago?

A desktop PC with a GeForce 980GTX (from the silent film era) and an Intel core i7 7700K.

What do I have now?

A desktop PC with a GeForce RTX 3090, the same CPU, and two little USB desk fans pointed at the GPU heat sinks on my open cased computer that sounds like a jet taking off.

How do I mine them?

I use NiceHash to run hashing operations on my computer and get rewarded in Bitcoin.

What’s the most important thing when mining?

• Your hash rate.
• Not burning your house to the ground.

But mostly the hash rate. The more hashes your GPU can compute per second, the more answers you submit to the mining pool. The more answers you submit to the mining pool, the higher rate of reward from NiceHash. NiceHash reward you in house tokens, fun bucks, imaginary bitcoins that don’t exist in the public ledger yet. They do this frequently (give you small rewards) and those small rewards incur no transaction fee. It’s only when you want your hard earned bitcoin to LEAVE the walled garden of NiceHash that you will incur a transaction fee. You will transfer your NiceHash imaginary bitcoins to a public wallet address (uh, YOUR address, that you hold in another system) and they will become REAL Bitcoins. You’ll pay a transaction fee for this. Then if you want to withdraw your REAL Bitcoins (as real as these magic beans can be) into fiat currency, stuff you can feed your family with, well guess what - more fees.

You will embark on a tweaking journey that will see you optimize your hash rate while keeping the GPU and memory cool (enough) on your graphics card. You don’t want catastrophic failure on your graphics card. It’s your ticket to financial freedom!

How do I tune my GeForce RTX 3090 to mine the most magic beans?

I installed MSI’s Afterburner to tweak clock and fan speeds, and grabbed GPU-Z to monitor my card’s vital signs.

I lowered my GPU clock speed because the hashing algorithm (DaggerHashimoto) utilises your graphics card’s memory more than its GPU. Having a lower GPU clock speed keeps the overall temperature lower without affecting the hash rate.

I overclocked the Memory because of the above reason for the hashing algorithm. This is where you will balance on a knife’s edge when it comes to three way trade off:

• Temperature
• Memory Clock Speed
• Hash Rate

You want the highest hash rate you can get without your Memory temperature going past sustainable levels. Anything below 110 degrees is considered OK (I googled around and couldn’t find any concrete advice from manufacturers). I wanted to keep mine below 100 though, because I don’t want catastrophic failure.

So how much do I mine?

110.8 MegaHashes per second.

Is that good?

I guess. NiceHash are “paying” me this much per day.

$13.18 AUD per 24 hours.

But wait, the sun isn’t up at night time

AHA! Yep. I shut down mining when I’m not drawing enough power from the solar panels in order to make this mining “free”. So I get about 11 hours a day of free mining. That makes the reward about $6 per day of net profit.

How much power do I use when mining?

About 370 Watts.

Is there anything particularly potatodeveloper about this?

Yep. I built an app that polls my solar inverter over a HTTP API (on my local network). The app finds out how much electricity my solar panels are generating. When that number goes higher than a certain threshold (700W) it will use NiceHash’s RESTful API to instruct my mining rig to start mining. When the number goes lower than that threshold it tells my rig to stop mining.

30 seconds later the same thing happens again, on a loop.

I run this app on my raspberry pi.

I set up Task Scheduler in Windows to start the NiceHash app (and wake my computer if it’s asleep) at 0730 each day. There is a “go to sleep” task set for 2000.

So my computer can do this dance of being woken up when the sun’s up, being told to mine when the energy is free, and being told to stop when it’s not.

I’ll see how this goes. I’ve only be on the task for a few days, but overall this has been a fun little project. Building the ghetto electricity cop app was probably the most fun.

Isn’t this whole thing risky?

Yeah, in a sense. There are many ways that crypto holders can become surprised. Your wallet (hosted in an exchange) being emptied is probably the riskiest item. To assuage my reservations about holding/trading in crypto I bought a hardware wallet and will go put the 24 word recovery phrase in a bank vault.

Next steps?

Wait for Telsa to release a Powerwall 3, buy one of those, and mine 24x7x365 😎