Topic: Any suggestions or experiences on using a voltage stabilizer/regulator (Read 462 times)

Just wanted to add the reason why I use (expensive) dual-conversion UPS's on my home miners: After a major 2-week long power outage around 10 years ago I had a permanent NG-fueled generator installed at my house. After I got into mining in 2014 I found that the genset does not kick in until the line drops 25% below nominal (in my area that = 172VAC before the generator starts) and of course the miner PSU's drop out around 200vac. Soooo, after trying some standby UPS/line stabilizers which dinna work because of the transfer times I settled on the Triplite and Cyberpower dual-conversion ones both of which seamlessly maintain 230V regardless of incoming line voltage without switching to battery down to below where the genset kicks in.

In the years since there were a few summers where several times the line got down to under 200v during the daytime so the stabilization was very handy...

For folks looking for line stabilizers for loads over 10kw definitely use only the motorized Variac types - they do not switch between discrete transformer taps. They use a carbon contact that slides over the transformer windings and so have no transfer time issues. Also more efficient than always changing AC>DC>regulated AC.

This is just some technical information so don't take my word in regard to miner specific use cases or even all computer PSUs.

But; all computer PSUs (at least since 1998; and this is as far as I remember xD) are switching power supplies which means that they are internally changing the frequency of the input power based on the output voltage and current. So essentially they are regulators by themselves and they usually have a range of 180v-250v; some even supports voltages as low as 100v. The only problem is that less voltage means higher frequency for the internal board and some of these boards have frequency limitations. Also added current to compensate for lower voltage sometimes results in melting connectors and wires. So they usually have a circuit to limit the current if the voltage drops by a lot or even turn off.

A >220v input voltage is actually good for switching PSUs as this means that they can run on a lower frequency and less current is drowned at the input. This also makes them more efficient as less energy is wasted. The regulation is achieved in switching power supplies by measuring the output voltage and trying to correct it by changing the frequency (all PC PSUs have this, only very simple low-end PSU have fixed frequency). This happens quite fast (way faster comparing to a relay).

Therefore you don't need a regulator on the line; you are just wasting more money and more energy as this regulators at best (Switching Regulators) convert AC to DC and then again to AC while this is internally done by your PSU once again and each time you lose some energy in form of heat. Simple in-line regulators are also useless as they have low efficiency because they regulate voltage or current by converting excess to heat; again.

In my small farm (24 devices; ~15KW three phases) I have a device (We call them Power Protector here in my country) measuring voltage and current and turns off all devices if the voltage drops to lower than 180v or reaches higher than 250v and this worked well for me in the last year. Had zero PSU failure but then again my power source is quite stable and the device never triggered except once due to a cable failure resulting in loss of one phase. It costs me like 70$ (including the Contactor used to turn power on and off). I also have a RasberryPi connected to 3 relay boards each of them connected to 8x15A relays allowing me to turn each device on and off separately and this part cost me like 14$ per each device and some 4$ for a separate cable to each device. Wrote a small application for the RP to turn devices on one by one after a blackout and this allows me to regulate the power usage on the three-phase power source and also I like to think this minimizes the risk of current drop (even tho all of miners if turned on with each other without mining take a total of 3amp on each line; so not much; however I heard that switching PSUs tend to drow a lot of current when first turned on but I need an oscilloscope to confirm this; so not sure.) when all of them get in line.

ALSO: Having a relay in line to switch power source is dangerous; being it in a UPS or any other device; these switching power supplies are huge; providing like 100amp power 12v to the miner and a sudden loss of power is less damaging than a complete 240v -> 0v -> 220v transition. Also, any other device using any sort of silicon-based relay is also dangerous as these devices tend to allow some current to pass through even in off stage and this confuses the switching power supply and might damage it. I strongly suggest a setup similar to mine and nothing more. A UPS is alright for a computer as it draws little current in daily usages and a 15ms transition is barely noticeable by the power supply as it has internal capacitors and they can happily run your system for 100ms to 200ms when used normally. But these capacitors can't do much when you run a miner drawing 100A and 15ms is enough for them to turn off and on again.

In conclusion, don't be scared of losing a PSU; these things have an expected lifetime and they tend to die sooner or later. Adding a regulator is a waste of money; adds more heat and the only thing it's going to change is that instead of your PSU it gonna die after some time and it isn't actually much cheaper than the PSU anyway. And even with it, you still have the possibility of your PSU dying. And don't be scared of miners and PSUs dying due to loss of power. They are far more sensitive to voltage fluctuations; therefore just put a device there to turn them all off when the line has a lot of fluctuations and you are good to go and spend the extra money on a better quality PSU for your miners so they work for longer duration of time and also keep your miner safe in case they decided its time to die anyway. Server PSU are strongly recomended.

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Btw if anyone is interested in a similar setup I found the following parts in Amazon with a quick search.

To control the input line you need a device capable of measuring voltage and preferably current and has an output relay like this:
https://www.amazon.com/YOKDEN-Multifunction-Electric-Frequency-Generator/dp/B07DCTX7K5

This is for three phases tho, for single phase, you probably can find a cheaper version. You also need 3 CT (one per each line) so you can measure the current:
https://www.amazon.com/Morning-Group-Current-Transformer-Alternating/dp/B07BGSBW52/

For the contactor you can take this:
https://www.amazon.com/Replacement-TELEMECANIQUE-LC1-D65-Contactor-LC1D6511-M6/dp/B00J9TTHAW/

For single phase, just buy a cheaper version (1/3 current rating of your farm) and use all three poles in series.

If you want to control each device separately, then you need to have one relay per each device, this is a good relay, but you also need a connector outlet for this relay that I couldn't find in Amazon:
https://www.amazon.com/Enclosed-Power-Relay-240VAC-SPDT/dp/B007ULO7FG

You can also find a cheaper one with lower current rating and use the connectors in series (10A with 2 Pole can happily pass 15A current when poles are used in series)

Then you can control these relays with a relay module like this:
https://www.amazon.com/chen499401077-Modbus-Protocol-Serial-Control/dp/B07MPBJQ3L

This module can be controlled over an RS485 connection and if you have a RP you need the following module to be able to communicate with these devices:
https://www.amazon.com/SMAKN%C2%AE-Adapter-Serial-Converter-Module/dp/B010723BCE

Then you need to write a custom application in RP to turn each relay after a delay; another good thing about a custom application if you are a software developer is that you probably can find a multimeter with RS485 port and get information about power quality to your RP and best of all view these values and control your devices remotely; you can also skip this part and buy multiple timers and use them instead of the relay board and RP to just turn them one by one after a predefined delay. Couldn't find a single pole timer relay on Amazon but these are available at your local electric store as these are quite frequently used with stairway lights.

In my opinion the money you would spend purchasing an industrial sized UPS (or several smaller ones) would be better used purchasing a grid tie inverter and solar panels which slowly lowers your power bill, something a miner would want in the long run...

UPS is still good pending the installation. Expensive yes but downtime can be as well for some. Essentially a small good setup you can forget about pending hardware issues.

I'd recommend a UPS, 4G LTE fail over if it's in the budget. Back generators too.

Bitmain's psu is the only reason I haven't bitten on a new unit, since adding a UPS isn't going to work for me either regarding cost.

I have not read all the comments but here is my take based only on personal experience.

i run my gears ( s9s , L3s, D3s, Z9 minis ) on very unstable voltage, it moves to as high as 235v ( very seldom) and drops to as low as (190v), the average is 220v but it's rarely stable.

never really had an issue with PSU , so far only 1 failed.

the funny part is this > i do have most of the miners run on a voltage regulator , the psu that failed was running on it, so i would only assume that psu would die either ways.

i use a regulator that looks pretty much like this but different brand > https://www.alibaba.com/product-detail/Automatic-voltage-stabilizer-5KVA-20KVA-single_62000979590.html?s=p

my set up is 3 phase, so i have 1 on each phase, they are supposed to do 10kw but since i don't trust these cheap manufacturers i only use like 7-8kw , and they regulate at range of 180v to 240v  , they always try to keep it flat at 220v.

but since i have more miners than what my 3 regulators can handle, i run some on unregulated voltage that goes from 190v to 235v as mentioned above.

never really had an issue, since all these psu are apws that suppose to run on 100-264V  as stated by bitmain.

now the S15 however is a whole different story, if you look here > https://shop.bitmain.com/product/detail?pid=00020190222170435964U2e2qb490657

you can see the min voltage is 200v while the max is 240v, so anything out of this range will probably damage the s15 psu,

they also state this on the s15 specs page.


also this in red


this means that they have probably tried those PSUs out of that range and burned them, they never really state such an exact voltage on any of the other miners, so i would be very careful using these S15s on anything that is not flat 220v.

* UPS is a big no > the cost is super high, why by expensive batteries that you never really going to use ??

* the voltage regulators like that one i bought cost me about 500$ each , i can't recall exactly those are bought long time ago.

there are also 20kw and 30kw that will surely cost cheaper as in price per regulated kw, but not sure about the shipping and stuff, you can't ship those using airfreight they are heavy as f, so you would want to use sea freight or try to buy them locally.

* keep in mind that there is a good amount of loss in power when using these regulators , that can vary. so DYOR

* also there are many scammers on alibaba and aliexpress so be extra careful.

My conclusion is that using a voltage stabilizer is not a good solution as well as a UPS

You can use the same types designed for large computer servers (eg: Blade).

In My Opinion™ an UPS is a bit overkill, and you need to replace the batteries every two years or three, adding to maintenance costs. An UPS simply switches to battery when something weird goes with the mains, while the "voltage regulator" tries to compensate the problem by itself. And yes like you say, they have response times as well so depending on the problem it might not prevent a reset.

Ideally the PSU is great and can tolerate a lot, but worst case they test it for China mains which is 230v @50hz like Europe.

Here protection would be the first goal, not so much a reset. Ie, don't let a voltage that would harm the PSU in. Second would be stabilize the voltage so input can fluctuate but output remains stable. Ie a low tolerance PSU that could burn with a 250v peak.

Of course a simple (cheaper) air conditioner/refrigerator protector could do the same, at the expense of more resets. If you have a large operation, make sure they have adjustable timers, to prevent them all going and coming at the same time...

A decent PSU should not let harmful DC voltages even when getting weird things from the mains... Someone would need to review and stress-test those new Bitmain PSUs to have a definitive answer. How much can they tolerate, how stable is their DC output regardless of input? Etc.

Google "UPS Transfer time" and "PSU hold-up time".

What happens is that the PSU very briefly shuts down then restarts causing the miner to reboot. Pretty much ALL standby UPS's have transfer times that are too long for mining use which is why the dual-conversion ones are best - BUT - being always on-line you do take a little efficiency hit.

What happened to yours?

Can we use a UPS instead of an stabilizer?

Just use those straps to move appliances lol Make sure your racks can hold it too.

Next time I suggest you take out the batteries. That's where most of the weight comes from... And because they are individual blocks, its easier to move them separately. Every 3 years or so you must replace them anyway (some people do it every 2 years regardless).

Ja. it certainly is a workhorse. Its very wide input voltage rane from around 150v or less and over 277v, the ability to set output voltage and freq to 50/60Hz makes it perfect for industrial product testing as well. Mine's set to 230v 60Hz. I got it through Overstock.com 'cause they take BTC last year back when BTC was still over $8k

At something like 185LBS was real fun to get downstairs: used a block and tackle to slide it down the the stairs. One helluva workout I tell ya...

I have been trying to figure that one out for my company already as the PSUs are 20v instead of 12v making our entire stockpile of PSUs obsolete.

Yea I remember your post on that in the other thread with your at home canaan settings. Really nice unit, something we're actually able to beat amazons pricing on but not by much.

When it comes to mining and using a UPS/stabilizer your biggest concern is the transfer time/switching time it takes for the UPS to take over or voltage corrections to be made. For efficiency reasons most UPS/stabilizers use relays and tapped transformers to make the changes and being mechanical devices relays take time to operate - anywhere from 5-10 or more ms. Unfortunately odds are the PSU's feeding your miner may not like that long of a dropout. I know mine didn't.

At home I ended up using dual-conversion UPS's like the Tripplite SU6000RT4UHV—6kVA that are always online changing AC > DC > AC and have zero transfer time.

My S9i with apw3++ has been fine with 248-252.  Mostly at 249-250. depending on time of day.

Last fall power company sank a new pole in front of house with new transformer to supply 2 new houses with a total of 5 houses supplied from the one.  Not sure once the new houses are occupied if I'll still be sitting at 250 or if I'll drop back closer to 240.

Until that first PSU problem was brought up with the input voltage, I was understanding that most everything was assumed to operate in that 220-260 unless specifically stated otherwise.  (obviously I'm referring to 200+ circuits not 120 lines)

I'm not the OP but I appreciate the research and testing, so that I'll be be better informed and what I should do or what is not necessary when I upgrade to S15 and beyond.

yeah  but we don't really know  if they will have a lot of issues at 241-247 volts.

I can tell you this that these two transformers are too costly and will only do 1 s15 not 2.

this one has a lifted ground = not too safe
this has 14 maybe 15 gauge wire input which can not handle 2 s`15's

https://www.ebay.com/itm/Norstar-5000-Watt-Step-UP-and-Down-Voltatge-Regulator-Transformer-Converter/332955089461?

this one wastes about 2.5 maybe 3%  to do the 220 volt leveling
it is 14ga or 15ga
the two 220volt outputs are chained wired internally  with 14 gauge wire should be 12.

and an internal wire had its insulation nicked and could short.

https://www.ebay.com/itm/Norstar-4000-Watt-Step-Up-and-Down-Voltage-Transformer-with-Voltage-Regulator/332607784072?

so while they are not super costly  they are not good enough to use.

larsonelectronics has better gear but it is not cheap

https://www.larsonelectronics.com/

https://www.larsonelectronics.com/p-153799-1-phase-buckboost-step-down-transformer-240v-primary-229v-secondary-at-4367-amps-5060hz.aspx

this should do 3 s15's  it most likely could do 4 but I would only want to do 3

it will cost 1-3% power loss  and at 197 plus shipping it is not that cheap.

it is just  a straight step down  which means  11 volts less  out then in.

so  if you have power that goes from 237 to 251 like I do it would be a decent choice for 3 units.

If you are going to run 5  units   you need a bigger boat so to speak.

this one could do 8 s15's

https://www.larsonelectronics.com/p-147785-.aspx  cost 673 plus shipping

it would drop power from 242 to 220  

you would need to feed it with a 150 amp panel then make outlets for the output.

But it is all conjecture since we are not fully sure how the bitmain psu's will stand up.

no one else has come forth to claim an issue with the psu's  so it may not be an issue.

I will say this the apw3++ can do 245 -247 with out any problems.  I have had very good luck with them and s9's

Unfortunately that is going to prove challenging with the latest Bitmain models, where the psu is customized. Which is a big issue if, for example the S15s failure rate at 240v really is higher than usual. Where do you get a replacement PSU not made by bitmain?

I made the assumption anyone with 'bad' power would know better than to run big power hungry devices like these so that didnt really enter my thought process.

The other recommendation would be to buy ihgher end server grade power supplies. If the cheap chinese PSUs are blowing up every 3 months, why not just buy something proper that has protection circuitry built in?

For me if my solar buildout was to end up with 20 s15s and 10 m10s

I certainly would not get cheap transformers.

I got the two not because I need them but to be helpful to people with a smaller build.

A garage miner with two s15 can not afford for them to go boom.

Both items I purchased were poorly made and would never handle 2 s15s.

So don’t get them.

Larson makes higher end models that can do two units but they are costly.

And remember only one person has confirmed dead gear in the case of psu issue.

Even though he thinks he was sending 245 volts to it. It only proves those psu stopped working for an unknown reason .

Ie he could have ran all 15 he had and only those two would break.

I did run my single s15 inverters night at 243 volts. Then got the first transformer delivered .

I know enough about gear to tell you no one has shown enough testing to prove the s15 will always burn up at 245 volts.
But if you routinely drift to 245 - 251 volts you need to be aware it could be an issue.