Does worth mining with used S9s?

[kalstr]

Hello,

I have found larger quantity of used S9s 13.5TH/S for 436‬USD (inc. shipping) per miner.

Does it worth buying them, I have free electricity up to 960kWh.

Also there is a problem, there are used s9s .. ROI per unit it's 4.6 months with the current profit. Can one used S9s works 24/7 for minimum of 5 months?

[kalstr]

Yes, you have right..

I found on Aliexpress for 385usd/free shipping.

But it's used, ROI for that price it's 3.9 months.. can this miner works 24/7 for min of 4 months?

[mk4]

I mean with free electric anything can be profitable, but that price is a bit high. Hell S9s are on AliExpress for $365 shipped with PSU.

Just to add to this, since you've said that the Antminers are used, it also heavily depends on how worn out these devices actually are. It's sort of "mileage"(for a lack of a better word) might be quite high already, potentially giving you significantly lower hashrate.

[kalstr]

What about another miner that have good profit if have free electricity?

[NotFuzzyWarm]

What about another miner that have good profit if have free electricity?

If you have free electric ANY miner is good. The question then becomes how much free electricity do you have: just a few kw or more? Please do remember that miners are hot and loud. Can you deal with removing the heat from where the miners are? Please ref the 1st time/small miners guide.

[PassThePopcorn]

What about another miner that have good profit if have free electricity?

As long as you have free electricity, getting a miner that is the best $/Th is what you are looking for. The things you look at when buying a miner is the cost of the miner and the price you need to pay to run the miner. If you remove the price you pay to use the miner (electricity) then you are looking at the price to acquire the miner.

960kwh would be about half of a S9, in reality 960kwh would be half of almost any machine out there right now. So that should be taken into account when figuring out what you want to get, especially if you only get 960kwh for free, this calculation of half a miner doesn't taken into any account of what your home uses.

[kalstr]

If you have free electric ANY miner is good. The question becomes how much free electricity do you have: just a few kw or more? Please do remember that miners are hot and loud. Can you deal with removing the heat from where the miners are? Please ref the 1st time/small miners guide.

I have free electricity up to 960kWh that is for 24h - 40kW running 24/7. Place when I will run miners will be in a warehouse so hot/loud it's not an issue.

As long as you have free electricity, getting a miner that is the best $/Th is what you are looking for. The things you look at when buying a miner is the cost of the miner and the price you need to pay to run the miner. If you remove the price you pay to use the miner (electricity) then you are looking at the price to acquire the miner.

960kwh would be about half of a S9, in reality 960kwh would be half of almost any machine out there right now. So that should be taken into account when figuring out what you want to get, especially if you only get 960kwh for free, this calculation of half a miner doesn't taken into any account of what your home uses.

Yes, I don't include electricity but problem is price of a miner & shipping is too high so I can't pay for a USED miner that have ROI 4-5 months. What if it's broken/lower hashes etc.

About free electricity:

1 S9 - 1.35kW
30 S9 - 40.5kW
960 kWh = 40kW

[PassThePopcorn]

I read the amount of power available wrong. Again when you have free power all you really care about is the $/th while keeping power usage under what you have available.

Mining has two costs:

1) Operating (cost of electricity, maintenance, internet, space).
2) Cost of the unit.

The majority of operating costs usually goes to the space and electricity, if you already have the space and the electricity is free this cost is not really there, so you are only left with the cost of acquiring the  miners, to maximize your earnings just keep your $/th low. The better the miners efficiency is the more you will earn per usage of power, meaning you will be able to run more miners with your free power so you will in turn earn more. With free power you just need to get the most hashrate for the lowest price.

[kalstr]

Do you have any suggestion with what miner should I start and where to buy?

I have talked with a seller on Alibaba for a used S9 and told me if I run it 24/7 it will be dead after 6 months... So with that ROI (without electricity) was 5 months so I had only 1 month to make a profit.

Please can you explain this "keep your $/th low" ... should I low hashrate to the miner so It can mine less and stay longer?

Thanks!

[PassThePopcorn]

$/th the dollars you spend per terahash.

With your example of $385 for an S9 @13.5th that would be $385/13.5 or $28.51 per terahash.

I'm not sure what the seller is talking about, I've ran S9's for over 2 years without issue, however I have also had them arrive DOA. It all depends on the environment they come from as to if they will last a long time. A miner that comes from a dusty, humid data center / garage will likely die quicker than one that was well taken care of.

I would check in the marketplace on this forum, there are some bulk deals as well as smaller offers.

https://bitcointalk.org/index.php?board=75.0

[kalstr]

I will check that section, thank you so much for the help.

[PassThePopcorn]

In other ways too it depends on the user, I sold an S5 locally and had the buyer contact me a month later saying it died. He had however overclocked it to fuck send had it out of the tunnel in a thing of coolant. It had been hashing away in my office in an A/C room undervolted previously not a dusty mine. It's all really just luck, and use case.

Well that's a being taken care of thing, you took care of it to the point where it could continue working for a long period of time. The buyer on the other hand ran it to it's max and in simplest of terms burnt it out. So I could have put in the wording of "It all depends on where it came from for the life" to "it depends on where it came from and where it will be", but I figured it's just common sense that if it matters for it's previous environment that it would matter for it's next environment.

If the device is well taken care of it will last in most cases.

[BitMaxz]

Have you tried to check this site https://www.asicminervalue.com/

You can see all profitable ASIC machines if you are not paying on electricity bill then this is a good choice and Im sure you will make more profit than buying a 2nd s9.

This is just a suggestion because there's no guarantee that the 2nd hand s9 will live long in mining.

[kalstr]

Have you tried to check this site https://www.asicminervalue.com/

You can see all profitable ASIC machines if you are not paying on electricity bill then this is a good choice and Im sure you will make more profit than buying a 2nd s9.

This is just a suggestion because there's no guarantee that the 2nd hand s9 will live long in mining.

I use that site but problem is where I can buy...

Official sites are out-of-stock, vendors there are completely scam. I have bought on cryptouniverse.at this Sunday and still Processing, I dunno if it's scam or out-of-business.. anyway I will see.

[Artemis3]

Yes, I don't include electricity but problem is price of a miner & shipping is too high so I can't pay for a USED miner that have ROI 4-5 months.. What if it's broken/lower hashes etc..

About free electricity:
1 S9 - 1.35kW
30 S9 - 40.5kW
960 kWh = 40kW

If you underclock them with Braiins OS you can even add more of them. By raising efficiency you can easily lower that consumption to under 820w each (@10T)... You could put 48 S9s, maybe some more if a few have damaged boards.

480THs vs 390THs using the same 40kW...

Make sure you check more sellers, i have seen S9s at $150 each...

PLUS, under-clocking tends to make them run cooler and last longer.

[kalstr]

If you underclock them with Braiins OS you can even add more of them. By raising efficiency you can easily lower that consumption to under 820w each (@10T)... You could put 48 S9s, maybe some more if a few have damaged boards.

480THs vs 390THs using the same 40kW...

Make sure you check more sellers, i have seen S9s at $150 each...

PLUS, under-clocking tends to make them run cooler and last longer.

Thank you for this idea it was really helpful.

150$ S9s? Please do you have any link or contact? All what I've found it's 385usd per unit.

[john139]

If you underclock them with Braiins OS you can even add more of them. By raising efficiency you can easily lower that consumption to under 820w each (@10T)... You could put 48 S9s, maybe some more if a few have damaged boards.

480THs vs 390THs using the same 40kW...

Make sure you check more sellers, i have seen S9s at $150 each...

PLUS, under-clocking tends to make them run cooler and last longer.

This is good idea , but as far as I can guess OP is really concerned with ROI or ROR   so I did want to do some calculations, just take a look at the table below I tried to put some numbers to make it more understandable.

Note that the green columns are same for both quantity so no matter what you put result will be same,   as well as BTC price ( i assumed 5950 $ you can put whatever you want ).

so u can see 29 pcs have better ROR.

http://i67.tinypic.com/2rwnuxk.jpg

[kalstr]

What power cable is needed for 48 miners?

[john139]

What power cable is needed for 48 miners?

If you are asking for cable which connects miner to the power , normal computer cables ( 2 x 1.5 ) I think will do but if you are asking for wiring of whole farm it depends on many factors you better ask an expert 

[NotFuzzyWarm]

What power cable is needed for 48 miners?

One big enough to handle the amount of power you are using. That in turn depends on your power line voltage, if using 208v then the 40kw you mentioned = 192.3amps feeding the circuit breaker panel. That gets split up depending on how much power each individual miners uses. For s9 and such (around 1,250w each) you can use a 15A outlet to power 2 miners.

You need to work with a licensed electrician to get the proper power outlets and circuit breakers wired per your area codes. If you do not do this for a living DO NOT just follow internet opinions about wiring. The risk of electrocution or fire is too great.