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There's been numerous heated discussions comparing solar power and grid power.
One thing that I have never seen being discussed is using solar panels without batteries, and mining only during sunlight, and not grid tied. 

Ideally, everything would work great when there is full sunlight and the solar panels are producing electricity at full capacity.

The part that I don't know is what might happen in the morning or evening when the sun is low in the sky and the solar panels are only generating a fraction of its capacity. 

Just for argument's sake, let's say the mining rig is an Antminer S1 drawing 300-watts of power at 12VDC and two 12V 300-watt solar panels providing 600-watts of power during peak sunlight.

My question is, what will happen in the morning and evening when the solar panels are only producing, say, 100-watts of power? Will the Antminer S1 work at a much lower hash rate? Or could it be damaged due to insufficient power? What if during the day, dark clouds came rolling in and the power fluctuates between 50-watts and 400-watts?

Is there some kind of pre-built device or protection circuit that can regulate the power to at least 300-watts? I suppose a small battery can be added just to normalize fluctuations so that the regulator won't cycle the power too frequently.

That's impossible because watts are a unit of power, not electric potential.

Power in watts is the product of voltage and current (in amps).

Dropping wattage at constant voltage means dropping current. There is no way to maintain constant wattage under these conditions unless you're supplying more current.

There is no such device.  Solar powered equipment uses a battery to buffer the supply and load.  To get optimal power out of the panels you will need a charge controller between the panels and the battery.  A charge controller alters the apparent voltage of the load to match the optimal voltage of the panel (which will vary depending on current conditions).  Slapping a panel to a fixed 12V load is going to kill 30%+ of your output.  

As for what happens if you supply a device designed to use 25 Amps less than 25 Amps?  Well it depends on what undercurrent protection the device has.  If it is none then it is very likely you could damage it.  I would not recommend hooking a 25A device to a supply which can not consistently supply 25+ Amps.

As for ways to protect the miners, unless the miner can be throttled down to use less voltage the easiest undercurrent protection (to protect the device and battery) is to measure the voltage of the battery.  As the stored energy in the battery is reduced (because device is drawing more current than the charger is supplying) its voltage will decline.  When the voltage gets "too low" (which will depend on battery type and safe max discharge) the connection to the load is cut by a relay.  Once the battery voltage reaches some min "cut on" voltage the connection to the to the load is restored.  If there is no commercially available system that meets your needs, building one is a pretty simple electrical project.

Any reason you want to be off grid?   Off grid is always more expensive.  You are adding an expensive charge controller and battery to an already expensive system.

The speculative device in question would be a perpetual motion machine, because the specifications indicate that its a device capable of producing a constant Joules/s given a dropping input Joules/s. That's the definition of over-unity. (The only exception being of course being if some of the total max load is being diverted to a battery like described).

I agree , but I would like to comment that a simple charge controller does not do anything than cutting the voltage exceeding the battery's characteristics.

A simple charge controller cuts the voltage when exceeds the 13.8V (for silicone types ) and 14.2V (for Pb types).
There is nothing else it can do. It makes nothing more than what a solar panel could do directly connected to the battery (except from protecting it from overvoltage).

There is also the case of an MPPT charge controller that , as you said, can offer an additional 30% approximate gain compared to the previous case.

But such a controller would cost more than twice than what an S1 does.

Lastly, using an S1 with current lower than what needs, would create huge HW errors. No damage can be caused IMHO.

I would imagine  it would make the miner unreliable at these times.
One minute there might be enough power, the next minute there wouldn't be.
The miner might switch on then off, possibly switch on, then not have enough power to complete the boot and remain in some locked state.
Ideally, you only want to switch on electronic equipment when you have enough power.
Solar panels are expensive.
Have you considered a used veg oil diesel system.

I'm sure it will not work because to do bitcoin mining tools require a great power,
but if the battery has a large capacity

Sunlight mining is a good decision but it remains to be seen whether the mining process is completed properly through sunlight. The more light that shines on the solar panel, the more electricity the solar panel will be able to produce. A place should be selected that receives a lot of sunlight for most of the day. But many times it can be seen that when the weather is interrupted by rain, the sunlight does not reflect on the solar panel as a result of which much less electricity is produced than the demand.

Again, many people may have the opinion of storing electricity through batteries. Storing electricity through batteries will not be of much use. Because the amount of voltage that can be obtained directly from the electric line is not possible to obtain the same amount of voltage by collecting electricity through the battery. 

So if you plan to do mining with the help of solar, it is a matter of seeing how successful it is.

It is possible but your device will keep going off and on and this could damage something, if your solar panel is 1000watt capable then taking 200 watt power from the 1000watt panel will be ease, there are still enough juice left so even of the buffer isn't balance, as far as it doesn't go below 250 watt your device will keep running nonstop, still, I recommend using at least two battery backup, the buffer will be more stable with battery backup.

Tottaly possible in place with high sunlight % but, some of those place aren't good for that, like Saara desert which people need to spend everyday to clean sand and dust from the equipments.

We purchased two separate invertors that claimed to be able to take the power from solar panels and discharge a stable 12 volts.

We used 6x 200 watt panels which should generate 1200 watts at 12 volts enough to run two s9 boards in a unit.  The power supply loads on the specialty inverters were not stable.

So we needed to put in a battery to get it to be stable.

used a few thousand in gear .  a big fail.

As the inverter did not do what is was advertised to do.

If the load was light bulbs it would fire up.
if the load was a psu it would not fire.

some cheaper invertors have lower output on peak load than written in sticker
could make sense having invertor with at least twice required power threshold

HI

I have been running a small mining shed  run off grid for 6 months now.

I have 2 x S9J's, S19 Pro and 3 x L3+ running from my 10Kw panels and 600Ah 48v Battery and 10KW Inverter Setup.

My intention was to use spare power to mine, the rest is used in day to day living.  So I wish there was a device that could switch miners on and off when there was more sun shining, I have to do this manually and with timers.

Now it is the start of Autumn I am seeing drastic changes in light as clouds can drop power from the panels from 8Kw down to 1kw in a second so batteries of some sort are needed to smooth out what can be used as spare.

I would see that if you did this on a massive scale it would just be worse eg 8oKw down to 10kw production and back to 80kw in a minute.

regards

Not sure why "TwoZeroes" commented on a topic from 2014 lol, but anyways, it's nice to see that people are still interested in the same thing, asking the same questions that have been asked 9 years ago, and it's nice to hear about your little project that's running on solar.

Based on OP's questions and many answers I see here and elsewhere, people need to understand that you MUST have batteries if you are going to be off-grid, it's not an option, on paper you could assume that your solar panel will output 12VDC and an inverter will convert that power to 220VAC and thus you will need nothing more in between.

In reality, the voltage coming from your solar panel is nowhere near constant, and the overall wattage coming out from your DC-AC inverter is never going to be stable even during sunlight hours, so you can't just install 300w solar panel and expect a 300w device running directly from the inverter to work without issues, you are going to need to greatly oversize your solar panels to account for loses/shades/clouds/heat and all that, and then depending on the setup of your solar panels (series/parallel or both) slightly oversizing might not be an option, and a very large oversize might get you pretty close to cost of buying batteries or going on-grid to sell your power to the power company.

It's also important to mention that things have changed since OP posted this, today's miners are no longer 300w miners, they are 3000W and above, that's a 10x growth, solar panels are not 10x more powerful today, not even half of that.

I am no electrician but I think the electricity you get from the panels is alternating current (AC). Which means the voltage of that current isn't stable. You have to store it on a battery first so you can have a direct current/stable voltage (DC) which you can use to power up most electrical devices and as far as I know, bitcoin miners also run on DC.

The small solar panel I purchased years ago had a DC USB output actually but do you think it will provide a stable current? Of course no... A cloud appears out of nowhere and bam, you machine stops. That's why you have to store that energy first so it will create a buffer.

We used high end specialty invertors. each was over 1000 usd  and rated for over 2000 watts.

The issue is the load from the psu is not resistive like a light bulb.

Even with higher end specialty inverters we could not get it to work.

My partner is an owner of a 20 year old solar company he has a lot of solar experience.

We were trying to sell a dog house with some ground mount panels so you could mine daylight.

Spent a whole summer and once you add the 100 amp battery you could run around 10 hours a day. Using a night time shut down. But the practical setup was a no go.
we even coated the s9s with epoxy to not worry about nighttime condensation.

Solar works with on grid if the power company gives proper excess credit for power in the day.

You earn 100 excess kwatts in the day and at night the power company sells it back to you on a one to one swap.

If you get that deal solar works.

You have got them mixed up, solar panels generate low voltage DC, asicminers just like most other electronics require AC at the PSU input, the PSU of course will have to convert that AC to DC to run the miner's chips, but you can't just feed the miner with DC and expect it to work, it won't for so many reasons that are not best fit in this topic.

Yeah you string the panels going to maybe 72dc  and then the invertor changes them to 240 ac or 120 ac.

If you want the exotic inverters that did not work with solar to inverter to 12 volt dc to l3's or s9's I can ask my partner to source the name.  But they did not work.

Maybe 2016 or 2017 was the summer we wasted 2 months doing tests.

the dog house was like this one.

https://www.chewy.com/frisco-dome-dog-house/dp/268388


I would need to spend time finding the actual failed parts so no one uses them.

Yeah a total mess but I can see where it came from, he said he bought a small panel that had a USB port, this is where the confusion started, there are a ton of small foldable panels on Amazon that have a DC output for charging phones or laptops, and there are small solar panels for security cameras also, as all of them run on DC on either 12 or 15W. I have one of those for emergencies when I go hiking but honestly, if it weren't so light compared to what I'm used carrying, one power bank is way better, but less funny!

Back to the issue at hand, I'm not sure how he is running those asics on 10kw panels, he has 2x1350, 3250, and 3x 1050W, so 9150W.
He is getting barely 10% excess so no way to run this setup but during the day as he won't have the time to fill the battery unless he shuts the miners way before sunset when he can still squeeze in 2-3 hours the equivalent of one full peak power hour of production to fill the battery for load balancing but this will get him even less running time each day.

It's hard to tell how someone got confused, but sure that mindrust isn't the average "post anything" kind of member, so I am sure something confused him along the way, I believe it's the fact that miners do indeed need DC, so to someone who doesn't understand much about the subject, they would not think that DC devices need AC power input, the logic behind it is not easy to understad.


Hard to tell how does he operates, his battery has the capctity of 28,800Kwh, so nearly 3 hours for the set up assuming 100% DoD, but if I had to guess, he is probably not running them at stock settings, S9s can run on Low-Power-Mode doing 750w range, L3s 600w range, and S19 1800w range. so we are talking 30-40% less power consumption for the whole set up, but let's hear from him.

I have been in the offgrid industry for 30 years and seen it change a lot, Solar and Battery Technology has changed a lot in the last 5 years.
The old panels used to use DC 12v nominal so going into a 12v battery was easy with a charge controller - but these installs were small by todays installs.

Each of my panels put out 35v DC and I have 10 in series giving 350v into the Changer Unit.  I have 4 Banks of solar at the moment.
The Charger goes into a 48v battery, this higher voltage is needed to lower the current.  I have big 250 Amp Fuses on each battery bank. if I was to use 12v battery then a 1000 Amp fuse would be needed - not safe.

For this reason it is not advised to just run straight into a L3 or S9, you should still use an inverter and the PSU for the Miner.
eg 1000w S9 can have 83 amps at 12v going into it, hence the multiple groups of wires.   And the wire length should be short to avoid voltage drop. so this limits how far away a battery can be from miners.

You can get combined Inverters and chargers for $800+ USD that can handle 5000W.  Cheaper than my first 4 solar panels 30 years ago.

Generally, the equipment used in mining requires high voltage current. If this line is connected to a power plant, the electricity bill is very expensive for miners, so many miners decide to use solar power to carry out their mining operations. But there are many challenges to be faced in performing this mining operation through solar panels using solar energy. Because the solar panels have to be installed in a place where there is a lot of sunlight, but if the sunlight falls for 12 hours, then how will the mining work be done when the remaining 12 hours are dark. 
The energy stored through the battery will not provide good support for mining. And one more thing is that many times the sky is cloudy and it rains, when there is not enough sunlight, enough voltage will not be sent to the mining plant, which will disrupt the mining operation. So these things must be considered before starting mining with the help of solar.

 Op that will depend on the country geographical zone. There are some places that you can't use solar panels without battery to mine bitcoin. Places like Niger Delta in Nigeria. That place is rain forest, though sun came out but it is not that heat that you need to mine bitcoin. So it is only a place that has hot sun from morning till evening can use solar panels without battery if not it won't work. Just the example I gave above, if you must use solar system then battery must follow for backup so in case the sun light is weak the battery can sustain the machine for the main time. The voltage of the mining machine is high and the machine needs a voltage that can sustain it for a period of time.

I just thought about this and would like to know if I can just switch my miner on and off and only mine during sun hour's, or will that not work at all? I could ask chatgpt but I'm a little old-school and want a human answer.

I don't know how the pools evolved over time. I guess I'm not getting any reward (tx fees, mining reward, etc.) if I am not connected 24/7?

That is actually sad/bad and holding back decentralisation and indie miners, because the resources needed to become sustainable are

Electricity and Internet. Both is still really expensive, especially in regions that actually have sun.

Bitcoin still does not have it's inception in the places needed the most, because there is no way you can spin on a ASIC miner (even if you could afford or get it gifted), and then have a stable and affordable internet connection and free electric (only day time).

But if we can do mining on day, get paid, have starlink or something, we might get there. I'm definitely here to try and it would serve Bitcoin extremely well if the community manages more decentralisation through home-nodes and miners and maybe a new internet protocol on top like threefold is doing it.

Yes you do get rewards. Most pools take at least a 1-day average hash rate to determine the % of pool work you do and have a minimum withdrawal limit so the time you DO spend mining means it just takes longer vs running 24x7 to reach the limit.

nicehash
viabtc

would work for you

Short answer.

You need batteries anyway.

Your hardware will keep going on and off without batteries.

I will advice you to go for cheap batteries if you plan to use grid and sun only, buy used batteries that still have some 65% life left in them, you won't be spending much on them, just to keep the hardwares running while the sun keeps fluctuating up and down..

Goodluck in your mining adventure.

I think that such mining is possible somewhere in the desert, where the sun shines constantly and there are very few clouds and rain. But without additional batteries and a backup power source, the equipment will be very unstable. You need to consider what the payback will be if the ASICs work only 12 hours a day.

I like your thinking...I tried it myself.


I used a few different approaches. But what I found is this:


Using a 24v->12v dc-dc buck converter to keep miners going without a battery directly to the miner after the buck converter.

The buck converter was 50A max continuous. Before this setup I tried the chips plugged into the battery directly which fried some chips after a few voltage fluctuations.

This is why you NEED AN INVERTER to stabilize your output voltage.

When the buck converter was connected into the battery it also fluctuated with clouds and such it shut the miner off when it got too cloudy and then would turn it back on but the miner would have to reset each time and it was not efficient at all. In theory I wanted to skip the battery to save resistance and get rid of having to replace them or use them. However I have found that batteries offer a "cushion" for the voltage fluctuations to be less and yes it sucks converting dc to ac then ac to dc again but if you don't do this it's not stable voltage and will fry stuff or at best just stop functioning for bits of time unstable.


In short the losses from conversion are necessary as a trade for stability.


The only idea you could still try or I could still try is to put the buck converter into the inverter for some stability. But still it's got no power "storage" when mining goes offline from wifi failure or whatever else.