Power a GPU mining rig with DC-DC PSU?

I’m looking into powering a GPU mining rig from solar power/batteries. Considering that the power source and sink are both 12V DC, using a standard AC-DC 110/220V PSU introduces an inefficient conversion step that could be significantly optimized using a 12V DC-DC power supply instead. These are actually available commercially with the purpose of powering a standard computer in a caravan or a car, but have a Watt output below what would be necessary for a mining rig with 6 GPUs.

https://www.powerstream.com/DC-PC-12V.htm (too expensive)
http://www.mini-box.com/M4-ATX?sc=8&category=981 (efficiency >95%, 50% load)

I would like to know if someone here is able to help with a solution.

I was wondering if it would be possible to use one of these mini-box PSUs to power the motherboard, disks, etc (making sure the PSU is not be able to draw power above 50% load) and then power the GPUs through the 12V additional power connectors for the necessary wattage, over what the PSU can provide. This extra power would come directly from the 12V DC battery, or stabilized first through some simple electronics. Would this work?

You’re asking an electronics question more then a tech question, you might be better served asking this over at the eevblog.com forums in the beginners section. Even still I will do what I can to answer your question:

The problem with powering directly from a battery is the voltage over time, a 12V SLA (Sealed Lead Acid) battery on charge normally sits at around 13.8V, and during discharge will drop to as low as 10V, as such you can not get away without using DC-DC converter. Since you will need decent current it may be much easier to run two in series to get 24V and then use a high current DC-DC converter for the 12V.

Since it all uses a common ground, it is safe to connect multiple circuits up to provide the various voltages. You could use a general purpose DC-DC converter like those used in trucks to power 12V equipment and then a DC PSU like the M4 you mentioned.

About the only thing I think I would add to this is a capacitor bank on the 12V rail for the GPUs, several high value (470uF or better @ no less then 15V) in paralell with the rail would suit. You also need to ensure you don’t over discharge your batteries as doing so will permanently damage them.

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I have been using an M3-ATX PicoPSU for many years. I have used it both with a power brick on grid and connected to solar without issue. As far as running a motherboard with drives, CPU, and even a very small GPU it has worked well for me.

I would drop the CPU voltage on whatever CPU you choose. If you find a T model Intel for the same price as a regular, then go for it. Otherwise it isn’t worth it to spend extra when you can generally drop the voltage significantly. I have no idea how it works with AMD so YMMV. My entire system with a 53 watt CPU G1850 Celeron), HDD, SSD, a couple USB devices, and single fan for the CPU was using ~30 watts idle and ~40 watts max with the CPU voltage down to 0.9V which was as low as my cheap board would go.

I would recommend going 24V and using step-down power converters for a more powerful setup than what I use. If I remember correctly, the PicoPSU’s step voltage down to 12V when it is too high, but when it is within a certain range it just let’s it through unfiltered. Also, it would likely work out better to have the motherboard PSU set to power down the system when voltage gets too low (say 20 volts) but still plenty of voltage to keep things running until it has shut down properly. That way you could just use dumb step-down converters to power the GPU’s.

Another benefit to using 24V is the solar power setup. It is usually easier to find larger panels running at 24V. Also, most of the solar charge controllers are limited by how many amps they can handle. You can hook up twice the amount of watts at 24V than at 12V, although you would want to confirm this with the manual for any specific solar hardware you use.

Personally I want to move to 24V to make it a bit easier once USB-PD becomes more common. I intend on running lines for 5V, 12V, and 19V with step-down converters. Running monitors, charging laptops, and running any standard 12V or USB/5V devices will be simple and I won’t need any other voltages off-grid except for large appliances or tools which would require a dedicated power source with my setup.

This method will provide consistent and clean power until the charge controller or PC PSU shuts things down due to low voltage, instead of possibly burning things up that are fed too low of a voltage before power is cut. That’s just my take on things anyway. You can find industrial step-down converters capable of delivering the power you need to run all of the GPU’s you want. This would be substantially more efficient than running power inverters just to convert the power back to what you need and the hardware would likely cost less in the end as well.

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Hello sorry to bring up this old post. I am interested in doing some build for mining at my home. I am considering to dedicate a full small room of the house just for mining. Go full Solar power and place insulation with a console running 24/7 on the small house plus the mining room with maybe 6-8 rigs running.

I appreciate your explanation in regards of the loss on converting the DC 12/24v to AC to then convert back to DC.

Please let me know if there is a way we can connect to maybe you can provide me with better recommendations since we area now in 2021.

Thanks in advance!

Every situation is different so it really depends on what the goals, experience level, resources available, and numerous other factors. I’ve seen a number of people wanting to make a fully solar powered ‘something’ when it honestly doesn’t make sense if your goal is saving money. If you want to learn something to build up to a larger project like solar powered mining then that is great! There are loads of tutorials for building knowledge and lots of resources for finding parts.

If you already have most of the hardware and using grid power then it probably doesn’t make sense to try to make mining rigs powered by solar. If you don’t have the rigs then there has never been a worse time to buy graphics cards. If you want to save money then solar hot water will pay for itself much faster than solar electricity. You could mine with whatever you have, install solar hot water, and use the savings plus mining earnings to expand on mining or buy solar electric.

The number one issue with solar electric on grid is the idea people can live exactly as they have been and just switch from grid to solar power and never have a power outage again. And of course you can, for tens or hundreds of thousands of dollars. If it were cheaper and didn’t require any thought to how people live or use power then there would already be billions of people making their own energy. It’s much easier and cheaper to use power already piped to your house and pay the bill.

Taking on this big of a DIY project is also somewhat problematic. As a person who is heavy into DIY, I can tell you that between changes in price, parts availability, technology, scale, and my own knowledge gains have completely flipped around many plans I had from just a few years ago. Limiting the scope of projects and following through has been immensely helpful. I’ve had a few projects when I was younger that were too big for my knowledge or budget at the time, and by the time I caught up the projects were never going to be what I had envisioned, and I no longer wanted it anyway. I still learned a lot from them, but I would have gone about some things very differently knowing what I know now. There doesn’t seem to be any way of convincing most people of how this happens until they learn the hard way. I know I did.

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Hi KleerKut,

That is why I read you and decided to contact you. Your experience and evolving on knowledge over the years must be broad.

I live in Puerto Rico and to be honest the power grid here is very old and inconsistent. I will eventually go to solar power anyways. I know the chips of the graphics cards are very expensive now, but I also know that I can achieve that ROI soon enough if I explore a variety of possibilities.

What got me here was the same idea as the post originator. I do not have to switch to AC in order to power the rigs.

I have a house with 5 rooms and I live by myself. The cost of electricity is rising due to there’s only one service provider and politics. My plan as I said before is go solar anyways but I can include power enough to power rigs and let the solar investment and rigs pay by themselves. I can seal one room which is 9’X9’X9’ just for mining.

The other thing is that I need to consider continuous connection to the internet. The service provider has occasional interment on service also if the power goes out in the area then I can have solar power but no internet. That situation will stop the mining process. I will have to find a direct satellite provider or pay for two internet services at the same time to assure connection to the network continuously.

I appreciate the time you took to reply back. Your experience is very valuable, and that is why I am here. I can learn from it so I can include things to consider at the time to decide/calculate if it is beneficial to invest on it or not. If I can, I do not want to learn it the hard way!

At least I have friends that are mining on a small scale but can help me build the setup. So it will be part DIY but with assistance from others which are willing to help. But with more ideas or points of view the possibilities amplify and something better can be achieved.

If you can recommend which tutorial to consider, please do so.

Please, tell me what you think about my plans.



The biggest problem with sealing up a room full of mining rigs is cooling. If you use electric powered air conditioning, it will use more electricity to remove the heat than to produce it. So for every 1000 watts of heat, you will need in excess of 1200 watts of cooling. And that is on top of whatever electricity it takes to keep the room cool on hot days without computers in the room. If this were an extremely cold climate it would offset heating bills, but it is terribly expensive plus hard on equipment in warm climates which makes it that much more expensive.

If you are looking at multiple mining rigs pumping out in excess of 10 killowatts continuously plus air conditioning, the scale of solar power you would need would be almost impossible fit fit on one roof. Geothermal would be much more efficient, but I only know of a few instances of geothermally cooled computers, and that is very much a trial and error affair, not something I would experiment with using expensive graphics cards.

It would be infinitely more profitable to rent the room out and invest that money. Sinking over $100k into this venture hoping it works sounds like a terribly bad investment. You could cut out all of that grief and just buy crypto on a dip and sit on it, but I’m not a financial advisor. If you were interested in learning about all of this for yourself, I would just start with one solar panel, charge controller, battery, and a laptop charger. You could get your feet wet and mine a minuscule amount while learning the basics.

I hate being a naysayer and always encourage people to learn and experiment, but even with free expert help I can’t see this being profitable.Using solar electricity to create heat is horribly inefficient, and it’s more than twice as inefficient in warm climates. I’m in Florida so I’ve seen first hand how much electricity it takes to remove waste heat. I still say go solar hot water first if you want renewable and reliable hot water with a quick ROI.

You are right, but I can start let say with a system that has continuous 20,000 watts and maybe one or two rigs. I just got to do the math in terms of how much energy the rigs plus the house electricity would summarize currently since I live alone there is not much electricity being used.

I plan tp put up an inverter that will run 24/7 which during day it will work a little more but just to maintain certain temperature to some rooms only, not entire house. With mining or not is a good idea to have a cool temperatures in the house for really hot days, once the cost of solar energy setup is covered then I only have to worry about maintenance.

For the solar hot water, I already had installed a hot water system (two panels and one tank) in the house. It works perfectly. If you mean a Solar Hot Water Electrical Generator please provide more information, I do not know about it.

What I am interested on is to have my house with an independent source of energy and the possibility of mining rigs in order to generate capital to achieve the ROI much sooner. I get the point of being inefficiently go use solar power in order to heat chips and then cool them down. But I will go with solar power anyways as is being more a more imperative where I live.

The idea to place more solar panels and more batteries is just there, I can keep building up/expanding the system.

Thanks KleerKut.