Direct DC Powering an Antminer ASIC With Solar / Alt Energy

[Longhorn901]

I have a prototype to direct DC power an Antminer L3+ from Solar and looking for anyone that would like to collaborate on this project.
This is a functional system mining on one, two or three hash boards depending on Solar Panel output.

Here is what the system consists of,

1) 5x 215 watt solar panels
2) 60 amp charge controller
3) 4x Trojan T105 batteries
4) Aruino micro controller
5) Antminer L3+

The system is set up for 12 volts with the charge controller regulating the charge to a max of 13 volts.
I am not using an inverter and power supply rather feeding 12 volts DC from the battery via a relay directly to the L3
The Arduino monitors the battery voltage, when the voltage drops below  12.1 volts it opens a relay shutting down the L3.
When the voltage rises above 12.9 volts the relay closes starting the L3.

The L3 is running Blissz firmware so the voltage and frequency can be adjusted to compensate for available sun.
This is done manually at this time but will be automated in the future with a control server that monitors battery state of charge.

The advantages of this system are,

1) Low cost power after system is paid off
2) Higher efficiency, looks like about 20% better than AC powered? Need to further investigate...
3) very eco friendly

The disadvantages are,

1) Can only mine during the day unless large solar system is deployed (not the intent of this idea, we want a simple low cost system)
2) Some assembly required

The basic idea behind this system is to deploy the lowest cost solar powered ASIC miner.
We only need a battery large enough  to get us through a short cloud cover, otherwise the system is shut down.
Batteries being the largest cost item in an off grid system we need to minimize them.

This idea should be scalable to any size of mining farm.

Things I'm working on,

1) Some kind of enclosure for the miners at the solar panels, needs to filter the air flow and protect from condensation. The miners need to be close to the panels to minimize cable losses.
2) The control server
3) Try out some Super Caps in place or in conjunction with the batteries
4) Automate switching in and out the number of control boards or the number of miners running dependent on available power.

Anyone doing anything similar or have some ideas?

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[Longhorn901]

Reserved

[philipma1957]

Reserved

yeah we used a large dog house.

but it was a fail too much morning dew the l3+  controller suffered and the psu jack to plug suffered.

we got clear water proof spray. and care fully sprayed the jacks and plugs once they were plugged in.

Our issue was the direct power inverters. that captures
the solar. it was defective and did not keep voltage stable.

The grid tied gear works better.

[Longhorn901]

Reserved

yeah we used a large dog house.

but it was a fail too much morning dew the l3+  controller suffered and the psu jack to plug suffered.

we got clear water proof spray. and care fully sprayed the jacks and plugs once they were plugged in.

Our issue was the direct power inverters. that captures
the solar. it was defective and did not keep voltage stable.

The grid tied gear works better.

Haha Dog house, that's a good idea!
Was thinking a somewhat smaller insulated steel or aluminum case with a low wattage heating element that comes on when the dew point gets close.

BTW, Just checked out your system, very nice!

[PNW_Steve]

Hey Longhorn,

Thanks for the invite!

You are doing pretty much what I was asking about.

I would love to hear the particulars on how you are controlling the miner "throttle".

Regarding batteries,  I just ordered some Lifepo4  for another project but I may rob some of them to try out on this project.  I have enough coming to assemble a 12V 1120A/H bank.

The ability to gauge solar production and battery state and throttling the miners based on available power.

I have some time to put it together.  Being at a Northern lattitude,  solar sucks in the Winter. Even worse,  we heat with electricity.  I am going to run my miners from grid power,  in the basement,  and heat my house with them until late Spring.  Then I will relocate into the garage and hook up the solar.

[PNW_Steve]

You can get away with longer runs between the panels and the miners if you run a higher panel voltage. My existing panels  are connected 2S4P and produce around 70 volts feeding the charge controller.  My charge controller is capable of  accepting up to 250v from the panels. For a given set of panels the higher the voltage the lower the current and the lower the voltage drop. With that you can get away with a  longer run between the panels and charge controller.

It's as easy as P=I*E 

[Longhorn901]

Hey Longhorn,

Thanks for the invite!

You are doing pretty much what I was asking about.

I would love to hear the particulars on how you are controlling the miner "throttle".

Regarding batteries,  I just ordered some Lifepo4  for another project but I may rob some of them to try out on this project.  I have enough coming to assemble a 12V 1120A/H bank.

The ability to gauge solar production and battery state and throttling the miners based on available power.

I have some time to put it together.  Being at a Northern lattitude,  solar sucks in the Winter. Even worse,  we heat with electricity.  I am going to run my miners from grid power,  in the basement,  and heat my house with them until late Spring.  Then I will relocate into the garage and hook up the solar.

Hi Steve,

My vision for this system was a self contained pod of the solar and miner in one unit that you could set up somewhere with the only outside connection needed being the internet.

I set the solar up a couple years ago to power a bunch of CPU miners on VRM. That turned out working pretty good but not worth doing.
So I'm re-purposing the solar for this idea.

So as far as the miner control at this point it's simply an arduino with one of its ADC inputs reading the battery voltage, when the voltage drops below a setpoint the Arduino opens up a relay shutting down the miner.
Then when the voltage rises above another setpoint it closes the relay which starts up the miner again.
Here's the program on github, not the most current but close...
https://github.com/TribeCrypto/Solar_Miner

I'm also doing some simple data logging and graphing to a server which was controlling the number of CPU cores mining in the old CPU miners.
That's how the system maximized mining, more sun more cpu cores running.
Maybe do something similar with the L3 by controlling the frequency but I might just switch in and out individual cards.

I know what you mean about winter and the sun, I moved from the northeast to South TX to get away from the suck part of winter

[Greatdev]

OP how much for the whole solar setup? Can you give an exact amount spent to build such setup? Maybe I can consider solar mining, I've been thinking about this for a long time now, the cost is why I haven't make a move yet, thank you

[Longhorn901]

OP how much for the whole solar setup? Can you give an exact amount spent to build such setup? Maybe I can consider solar mining, I've been thinking about this for a long time now, the cost is why I haven't make a move yet, thank you

It depends on a few things, my test system parts where purchased more than 2 years ago so I can't give you a good answer on price.
Your main cost will be solar panels.

What is your daily sun exposure? Here it's average 5.5hrs for the year, I need 10 panels if I want to run an optimized L3+ or S9

Do you want new or used panels? Here we can buy used panels cheep, like $30 for 270 watt panels

The batteries are only for getting you through a short cloudy period, so one or two 100amp hr deep cycle batteries will do. $100 - $200

I am using a Xantrex C60 charge controller About $140

The Arduino and relay will cost under $30

Then you need all the cable and odds and ends to put everything together.

So you can see, it depends, if you are good at scrounging things you can put something together fairly cheep
If everything is new I don't think it is worth it, then you are better off having a grid tie system put in for your house and run some miners off of that.

[Longhorn901]

Found a case that should work.
Need some cutouts for air in and out and two shelves.
This case will hold 4 Antminers.

[sxemini]

Nice, please keep us up to date 

[Longhorn901]

A little progress today.
I added a shelf and exhaust cutout for two miners.
Now I need an air inlet that can be filtered.

[miner29]

May want to get a little space between the two units.  The hash boards up against those walls next to each other will be the hottest spot.  Maybe an inch or 2 if possible.

[Longhorn901]

Good point, I'll have to keep an eye on temps.
I've seen guys stack them this way when they do a six board mod on the S9's.

If temps are a problem I'll have to add another shelf below for the second unit.

[Longhorn901]

More progress.
All primed up...

[Longhorn901]

Control circuitry and power cables installed.

[Longhorn901]

Anyone on here have information about measuring due point?
I need some type of sensor that the Arduino can measure and turn on some type of low wattage heating element.

Or another idea is to run an SBC CPU miner 24/7 or just overnight for heat??? Ideas?

[Longhorn901]

Just got everything connected, making Litecoin with light 



Only running one hash board now, it's overcast and the panels are only making about 9 amps.

[Longhorn901]

Here's a pic of it mounted to the solar panels.
I know I know, the wiring   but it's only a proof of concept.  

[Longhorn901]

Here's my idea for condensation control.
It's an Atomicpi CPU mining Verium.
It should give enough heat to keep the condensation away. 

[miner29]

Might want to plug some of the open holes dont want anything building a nest in it.

[Longhorn901]

Yup, that's on the list, them damn mud hornets are bad here in the summer.

[miner29]

Yup, that's on the list, them damn mud hornets are bad here in the summer.

Whole new meaning to de-bugging 

[Longhorn901]

The system is working better than expected for the past 3 weeks now.
There's a couple things I need to address though,
1) When changing hash rates the miner stops mining therefore the current draw drops off causing the battery voltage to spike up to around 14 - 14.5 volts.
     I'm thinking to add a relay between the solar panels and the charge controller to stop the charging until the miner comes back up.

2) With a small battery bank the batteries get hammered hard when fast clouds are moving through all day.
     Probably this would be a good application for supper caps.
   

[Funkyoid]

I’m new here but I’ve done the same thing. Only not used an arduino. Can you run me through how I’d do this. I’m more than happy to collaborate on this too, it’s my current mission to get it fully working.

[alevchuk]

The system is working better than expected for the past 3 weeks now.
There's a couple things I need to address though,
1) When changing hash rates the miner stops mining therefore the current draw drops off causing the battery voltage to spike up to around 14 - 14.5 volts.
     I'm thinking to add a relay between the solar panels and the charge controller to stop the charging until the miner comes back up.  

As I understood the Arduino is for limiting voltage coming from solar but gets tripped when miner decides to draw less power. I'm trying to setup an S9 Antminer on solar. As a beginner starting with DC to AC inverter and AC to DC "power supply unit" yet can't help but wonder if I should go straight DC to DC. What is your estimate on the efficiency gain from eliminating the AC step?

[skablast]

I am trying to understand why you would like to go DC DC

I have a 10 kw solar and 3 rigs working on 220v in an Island configuration without being attached to the grid
If I compare the production of the solar hybrid inverter system (with 27 Kwh lithium batteryDC/DC)  with what has been used by the rigs the loss of the inverter is 5 % max.

I

the 5 %  is worth the effort ?

[Skinny48]

ASICS miners are power consuming that's why they are bad news for solar energy unless you are ready to invest more on the panels, here is the deal


If your ASIC draws 1500watts make sure your solar panel is double of the watt meaning you should invest on 3000 watt solar panels because you will have enough energy to charge the battery while you are mining so once sun is down you will have full batteries to mine for extra hours until the next day

[GreenHash]

Keep us informed

[alevchuk]

I am trying to understand why you would like to go DC DC

I have a 10 kw solar and 3 rigs working on 220v in an Island configuration without being attached to the grid
If I compare the production of the solar hybrid inverter system (with 27 Kwh lithium batteryDC/DC)  with what has been used by the rigs the loss of the inverter is 5 % max.

the 5 %  is worth the effort ?

27 Kwh battery sounds massive. Does that run the rigs 24/7? I agree, a 5% win would not be worth the effort. Thanks! - This is what I've been looking for. Btw, that's only the loss on the inverter (DC to AC). The S9 power supply (AC to DC) has a small fan on it. How much additional loss do you get on the power supplies? I'll presume it's additional 5% loss. Panels are cheap so provisioning extra power for that would not affect CapEx. Do you think eliminating the inverter and power supply would significantly reduce CapEx?

[diggory_cedric]

Hi Longhorn, I am looking to undertake a similar project. I have a converted School Bus that my family and I lived in for about 4 years that is now parked on a friend's farm after we moved back into our house. The bus has about 2000W of solar on it and I have about 1000W of extra panels I could connect to it. I wonder if you ever got your project up and running on 12V DC?

[JayDDee]

Off grid mining is not practical IMO. Mining needs reliable power to run the rigs 24/7. As they say in trucking: "if the wheels ain't turnin
the rig ain't earnin". There are many benefits to a grid tie-in especially if you get credit for excess production.

Off grid solar is best when you have a specific load that matches the solar cycle. Air conditioning comes to mind as an example.