My residential Solar + Mining farm

[NiHaoMike]

Unless you live in the desert, even with MPPT, the voltage won't be stable enough.  The moment a cloud hits a panel, you're going to see voltage swings without a buffer.  If the 5-8% loss is of that great concern, having a battery as a voltage buffer is the safest way of doing it.  Not to mention the PSU and GPU don't keep a stable draw, it varies constantly.  The MPPT needs something to power track against.  If both the power source and load are constantly varying, that's not the best.  

I think the OP is on the best route.  Operating large solar systems at 12V is NOT cost effective.  The cable sizing required to bring the amount of amps from any length of distance at 12V is outright impossible and certainly not cost conscious.  Keep in mind there are MANY factors in the overall efficiency of a solar system, cabling and inverter are certainly big ones.  Having the solar system bring in the high voltage (the whole point of strings) and invert it (that inverter is likely 98% efficient) to clean 120VAC is worth the few % lost.

I was a solar designer and installer for almost a decade and the question of can I do this right off the panel came up very often.  I have a very similar mining/solar set up myself.

The normal PSUs running from the mains hold the voltage constant. The hacked PSUs (that accept on the order of 300V DC and perform MPPT) just take load off the normal PSUs when solar is available. Could also just tap into the primary side DC bus with one set of PSUs but then the solar setup will have a connection to mains, probably causing problems when connecting many PSUs together.

For my setup, I can (and have) run it without a battery if I add a PSU with a series diode, connecting it where the battery would normally go. It just wouldn't be efficient at using the solar panel since the miners only use 16W or so and the 100W panel almost always makes more than that during the day.

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[TRexMcStubyArms]

Unless you live in the desert, even with MPPT, the voltage won't be stable enough.  The moment a cloud hits a panel, you're going to see voltage swings without a buffer.  If the 5-8% loss is of that great concern, having a battery as a voltage buffer is the safest way of doing it.  Not to mention the PSU and GPU don't keep a stable draw, it varies constantly.  The MPPT needs something to power track against.  If both the power source and load are constantly varying, that's not the best.  

I think the OP is on the best route.  Operating large solar systems at 12V is NOT cost effective.  The cable sizing required to bring the amount of amps from any length of distance at 12V is outright impossible and certainly not cost conscious.  Keep in mind there are MANY factors in the overall efficiency of a solar system, cabling and inverter are certainly big ones.  Having the solar system bring in the high voltage (the whole point of strings) and invert it (that inverter is likely 98% efficient) to clean 120VAC is worth the few % lost.

I was a solar designer and installer for almost a decade and the question of can I do this right off the panel came up very often.  I have a very similar mining/solar set up myself.

The normal PSUs running from the mains hold the voltage constant. The hacked PSUs (that accept on the order of 300V DC and perform MPPT) just take load off the normal PSUs when solar is available. Could also just tap into the primary side DC bus with one set of PSUs but then the solar setup will have a connection to mains, probably causing problems when connecting many PSUs together.

For my setup, I can (and have) run it without a battery if I add a PSU with a series diode, connecting it where the battery would normally go. It just wouldn't be efficient at using the solar panel since the miners only use 16W or so and the 100W panel almost always makes more than that during the day.

Correct which somewhat defeats the purpose of Maximum Power Point Tracking.  The battery will store the energy that otherwise just turns into heat.  If you're not utilizing the potential of the panel at all times, you're wrecking your ROI versus what you get off the grid.

Also if you're doing this off a 12 volt panel and using it at a 12v power supply, you're artificially dragging the voltage down using the MPPT (unless your input tolerance is way higher).  This makes cabling costs and voltage drop an even bigger factor and a full stop for anything larger than 1000W.

[flippener]

It's not going to work...

You haven't factored in the draw when you're charging your Tesla and I know you want one!

[phuocduong]

cost of build solar?

[kuroman]

We have night-time tariff but it is on a separate meter called controlled load (off-peak). It also needs approval to connect to things like hot water and pool pump. It must be hard-wired and connecting anything else to this is illegal.

A residential customer can at any time change from a 'flat-rate' plan to a 'time of use plan', which has lower night-time rates, but you are killed during the double hump morning/afternoon peaks - up to 40c per KWh at those times. They are just outside my generation window. But I'll admit that I haven't looked too deep into this and will do so after your reminder.

Australia commenced solar incentives in 2009 and initially the feed-in tariff was 60c. This was heavily exploited and nerfed to 6c within 2 years. So today at 13c we are quite happy.
The other type of incentive is a rebate of about -30% install costs.
Typical usage-based solar systems in Australia have a payback period of 4-5 years.

No, I do not have a battery. When they are cheaper, I will definitely get one.

First of all thanks for the reply.

I see so it's quite different and you have alot of constraint with the off-peak power, unlike here, but it might be because here in France we get most of the electricity from nuclear so it's pretty cheap and abundant.
I think one, should do a simulation comparing both, there must be someway to simulate your powerusage vs time vs the variable rate.

4-5 Years sounds really reasonsable for a payback I think it's pretty interesting to do such a project especially when you couple it to mining.

As for batteries the Lithion/Ion or polymer packs are still way too expensive even if the solutions such as the Tesla one are quite interesting, on the other hand the old acid one are pretty cheap I think but dunno what are the price in Australia especially considering import tariffs and what's not, the battery should help with excess power but more importantly making you graph look linear.

[NiHaoMike]

Correct which somewhat defeats the purpose of Maximum Power Point Tracking.  The battery will store the energy that otherwise just turns into heat.  If you're not utilizing the potential of the panel at all times, you're wrecking your ROI versus what you get off the grid.

Also if you're doing this off a 12 volt panel and using it at a 12v power supply, you're artificially dragging the voltage down using the MPPT (unless your input tolerance is way higher).  This makes cabling costs and voltage drop an even bigger factor and a full stop for anything larger than 1000W.

If you make sure the load is always at least what the solar panels are capable of producing, then the full power generated by the panels can be used. The remainder will be pulled from the mains. You can even have just some of the panels supplying the hacked PSUs with the remainder supplying an inverter as is usually done. In that configuration, the required inverter will be quite a bit smaller, since those aren't cheap. (The idea of hacking a hybrid car inverter into a solar inverter/rectifier is an interesting one since those are dirt cheap for their power capacity, but requires a very expert level of electronics knowledge.)

[mittooss]

Excellent project, feeling jealous of you. It is really a great way to use solar power in mining.

[NiHaoMike]

Excellent project, feeling jealous of you. It is really a great way to use solar power in mining.

I have to admit that I'm jealous of my best friend Naomi Wu! Not only is she smart, she's very beautiful and artistic. I kind of wish I could be as good looking as her so that I could host a nice TV show of my own.

I also have to say that another one of my friends, Allie Moore, is really jealous of me now. For a bit of background info, she and I have been trying to "one up" each other in going green. That kind of slowed down once I got a Prius since she couldn't afford a new car, then she needed to replace the HVAC system in her house so I suggested one of the Gree smart systems. She didn't care very much about my cryptocurrency mining (not even how I largely focus on energy efficient coins), but add the solar and the fame and I managed to rise to a level that would be very difficult for her to one up.

To get back on topic, the best way we could promote solar power is to share information on how to build effective DIY solar setups. From beginners who need a bit of guidance to put together their first solar power system to experts who design open hardware for use in solar power. Solar power and cryptocurrency mining unfortunately don't tend to go together as a good investment. For those who have built large solar mining setups, what are they planning to do with the solar panels once mining is no longer profitable?

[TRexMcStubyArms]

Correct which somewhat defeats the purpose of Maximum Power Point Tracking.  The battery will store the energy that otherwise just turns into heat.  If you're not utilizing the potential of the panel at all times, you're wrecking your ROI versus what you get off the grid.

Also if you're doing this off a 12 volt panel and using it at a 12v power supply, you're artificially dragging the voltage down using the MPPT (unless your input tolerance is way higher).  This makes cabling costs and voltage drop an even bigger factor and a full stop for anything larger than 1000W.

If you make sure the load is always at least what the solar panels are capable of producing, then the full power generated by the panels can be used. The remainder will be pulled from the mains. You can even have just some of the panels supplying the hacked PSUs with the remainder supplying an inverter as is usually done. In that configuration, the required inverter will be quite a bit smaller, since those aren't cheap. (The idea of hacking a hybrid car inverter into a solar inverter/rectifier is an interesting one since those are dirt cheap for their power capacity, but requires a very expert level of electronics knowledge.)

Man if you have the time, knowledge, and parts to make a hybrid inverter into a solar one, more power to you!  Yea that's totally a pun, but truly a very fun idea.

[HansHagberg]

48 V DC power supplies
https://www.powerstream.com/DC-PC-48V.htm

Efficiency seems to be around 75%, which is less than impressive.


Supermicro also has some:
http://www.supermicro.com.tw/products/nfo/power_supply.cfm?pg=PWS&type=-48Vdc#type
Don't find any info on efficiency but likely much better.

[martyroz]

Have you thought about finding a way to feed the DC from the solar panels directly into the 12V consumers and bypass the two transformation stages?

My Inverter is quite efficient at max 98.1% efficiency. Typical is 97%. Platinum PSU's are 93%. It's important to note that at this stage, my mining consumption is just 15% of my peak solar output. So the vast majority of generation is feeding back into the grid and earning me money.

What do u say is more econmoical adding more rigs and increase revenue or add solar power and decrease power costs

I basically filled my roof with solar panels. I have one orientation that is 30% less effective due to being south-west. It aslo has shading issues from a neighbouring 2 storey home. So I put as many up there that I could and that's that. I encourage all to do the same but obviously different countries have different economics for payback.

What's coming down from his panels aren't 12V, they're likely strings somewhere in the 150-300V range.  Even individually, larger panels like this individually are above 25V themselves.  Not to mention the solar power isn't constant enough; you'd be varying input voltage constantly.  You need the inverter to smooth it out and make it a clean and stable power.

Correct. Each 'string' is 360V. The North orientation is 360V at 18A and the East orientation is 360V at 36A. Each panel is 30V.

Look nice mate, nice solution, but how much time do you expect to ROI, must have cost quite a bit 

PS : please clean up this CPU fan on your rig   

I calculate the solar installation to ROI in 4.5 years at absolute worst case scenario (where 100% is export). So we will be far in front of that. I justified the solar on it's own before I added miners into the mix.

It's not going to work...

You haven't factored in the draw when you're charging your Tesla and I know you want one!

They can't build them quick enough for me

cost of build solar?

$18,500 AUD ($14,000 USD) With a better than 4.5 year payback. From crypto earnings and tradings, I have paid for all computer equipment and 25% of solar install already

As for batteries the Lithion/Ion or polymer packs are still way too expensive even if the solutions such as the Tesla one are quite interesting, on the other hand the old acid one are pretty cheap I think but dunno what are the price in Australia especially considering import tariffs and what's not, the battery should help with excess power but more importantly making you graph look linear.

Batteries would need to be half their current cost for me to consider it. The problem I have is that I can store 60KWh per day and batteries are $10,000AUD per 12KWh...

[NiHaoMike]

Batteries would need to be half their current cost for me to consider it. The problem I have is that I can store 60KWh per day and batteries are $10,000AUD per 12KWh...

Nissan Leaf modules are going for about $200/kWh, probably even less in quantity. There are also LiFePO4 cells which are even cheaper (like the ones I used in my setup) but building up a sizable pack out of those is a lot of work...

[m1n1ngP4d4w4n]

I calculate the solar installation to ROI in 4.5 years at absolute worst case scenario (where 100% is export). So we will be far in front of that. I justified the solar on it's own before I added miners into the mix.

Oh damn, this is a nice ROI, here if you can ROI in 15 years you are lucky. Not enough sun  

Keep up the good work, it's awesome  

[fmz89]

try use regulator direct to mobo&GPU rather than using inverter to psu, you are losing 30%-40% efficiency

[cryptojanne]

Where is this? United states of Trump?

[martyroz]

Where is this? United states of Trump?

Hi all. I live in Australia...

I've added the second shelf and some cooling. I'm currently waiting on 4 * Vega64 and a few 1070ti's in post... more pics next week!

[VyprBTC]

Anyone thinking about going solely strictly for mining, just stop it already lol.

I do have a 10kw panel on my house, we got it before I started mining, it is currently producing 20kw/day in the summer it was doing doing about 40kw/day.

Basically it barely offsets 1 rig lol. So if you're thinking you're going to plop down 40k to offset the power cost of 1 or 2 mining rigs.... you're a bad dude lol

[hanskan]

I paid $6200 for 5kW system (Perth WA), it is producing 10MW ($2500 worth) per year, and I sell absolutely nothing back to the grid, so the ROI on the solar is 2,5 years, which is bloody awesome.

[hanskan]

Anyone thinking about going solely strictly for mining, just stop it already lol.

I do have a 10kw panel on my house, we got it before I started mining, it is currently producing 20kw/day in the summer it was doing doing about 40kw/day.

Basically it barely offsets 1 rig lol. So if you're thinking you're going to plop down 40k to offset the power cost of 1 or 2 mining rigs.... you're a bad dude lol

You must be retarded if you going to pay 40k for 10kW system lol

[toptek]

were hoping to be solar by next summer and were not renting it because the GOV perks you should get even if you rent or part of it  you don't get but if you Buy it you get it all, to me the company's that rent out solar are F*** you over, all you get out of it is maybe cheap Electricity no increase in poverty value etc ... and they get 1000's in cash you should get even if you rent for going solar.. but that's how the GOV set it up ripe off the little guy and give it to the rich ... an that tax cut they want to do to us in the US is bad ..... which is not law yet.



Don't pay 40 k for any solar system on any house/home the Price is dropping that fast .. at most you should only pay 10k if that Ive seen some system were i live go for 7k for a 10kW system or less  ... i would shop around before buying a solar system for a house/home and don't rent.

Where is this? United states of Trump?

I wonder to , don't worry that a-hole won't be around much longer and i hope the democrats learned from this once they get control back an they use it right ...after all every thing we have in the US was done for the people by the people or by the Democrats with the Republicans fighting it all the way an once the Republicans got control they can't get shit done  an what they want to do will hurt us an make things worse, i always thought it was the Democrats causing problem's like all most everyone was saying, was i wrong  ..I learned a lot with the want a be dictator we have for a President in the US. I'm 61 and never really read the  Constitution for the United States of America in detail with trump I had to.

cost of build solar?

Avg cost in the US around 5 to 10k or less for a full solar system you can use like you do normal Electricity .. but buy it don't rent it .

You can buy a Portable system but I'm not to sure how well they work and are they worth it ? ..just for mining if that's what you want .

i want full solar so i don't have to pay the Electric Company like i do now i know i may have to for night time use but selling to Electric Company is a nice feeling knowing they have to buy it back by law in my state ... an I'll max run it because i can ...

And i was told don't know how true it is, you can buy it over sea or out of the US even cheaper the reason the cost is so high in the US is greed and what GOV lets them do to us and there not held accountable for most of it, so they keep doing it .