Ever Decreasing Hash Rate

[imteamleader]

Hi,

I'm still just learning the basics of mining and I am running into a problem with my effective hash rate dropping off.

I have 12 x Avalon 6 miners. When I start the set up running I get around 35 to 40 Th/s, which run around there for approximately 8 hours then begins to die off. I have had it drop all the way to under 10 Th/s. This seems to keep happening.

If I turn the breaker off feeding the miners and turn it on after 30 seconds it restarts back to the rate I expected to be getting.

What is causing the die off?

The hash rate in Cgminer Status seems pretty constant. I have been reading that its just luck how effective yous hash rate is, but it never goes back up again. Is my internet the issue?

Set up is 29-30 degree C on the center shelf. The air is vented outside via a manifold, with a couple of take offs to heat the main floor of the house. I have fresh air being brought in.  The set up is powered by its own 100 amp panel.

I think I did find adding more venting help it stay higher for longer, or maybe this is just a coincidence.

Any though would be very much appreciated.

[1714063509]

1714063509

[1714063509]

1714063509

[Steamtyme]

That doesn't sound like a coincidence I think your miners are overheating possibly, but would need more info. What do you see for your individual miner stats? I haven't run the Avalon 6's but if you can post some screen caps of your miner logs we might be able to see something. What is the room temperature like? Also are all the Miners on the same breaker??

[philipma1957]

12 x 6 miners   35-40 is correct.

so questions are your exact make and model of the psu's

you clocks for the avalons

your circuit breaker setup

12 units use  10 kwatts to 14 kwatts  depends on clocks.



humor me and try running 9 units

see if it drops  from say 30 to 9 th

[imteamleader]

That doesn't sound like a coincidence I think your miners are overheating possibly, but would need more info. What do you see for your individual miner stats? I haven't run the Avalon 6's but if you can post some screen caps of your miner logs we might be able to see something. What is the room temperature like? Also are all the Miners on the same breaker??

I think the miner temps seem pretty constant, does this help.

https://ibb.co/fU3gnb
https://ibb.co/dS7P7b

These are taken 19 hours after a reboot. The hash rate has dropped from in the 40s to in the 20s. I decided to restart everything as I have waited before and it drops even lower.

This is 30 mins after restarting

https://ibb.co/c3zqDG
https://ibb.co/hwQK7b

The temp in the middle of the rack is 30C. I don't have the temp from anywhere else in the room.

12 x 6 miners   35-40 is correct.

so questions are your exact make and model of the psu's

you clocks for the avalons

your circuit breaker setup

12 units use  10 kwatts to 14 kwatts  depends on clocks.



humor me and try running 9 units

see if it drops  from say 30 to 9 th

The PSU's are as follows

9 miners with 2 each x https://ibb.co/nJ8YYG  and  3 x https://ibb.co/k3QDYG (powered with 240v)

Each miner is on a dedicated 15 amp circuit. The first set of PSU's are in the same circuit for the same miner. The 240v PSU's have there own dedicated 240v circuit.

I have not touched anything else with the miners or PSU's.

Bit of an update my end.

I don't think I have enough air coming in, which is causing other problems. I have the miners venting basically into a wooden box (18"x36"x78") with a 10" fan https://www.princessauto.com/en/detail/10-in-2-speed-ventilating-fan/A-p0772384e ducted out of the window. The fan is running at 690 CFM. With the 12 miners fans running at about 18CFM means they exhaust fan is not strong enough to remove all the air the miners are pushing. Would this strain the miners.

The air intake is only a small inline fan needed to meet code as the basement is a separate suite (90CFM). I though this would be ok for cooling as its now below 0C here so the air coming in is cold. I'm thinking this is nowhere enough inflow.

Also, silly me. I removed the cold air intake from the furnace as I wanted to move some of the hot air to the main floor. To do this I needed to cut a hole in the furnace room. Now I have a bulk head linking the mining room to the furnace room and I think the negative preassue is pulling the exhaust gasses in from the hot water tank. I was starting to not feel so great so think it was the CO2 coming bad into the house. I have shut down the mining last night. I will be patching the holes today and try running 6 miners to see if that is stable.

Is any of this enough to effect the effective hash rate, as the hash rate in the pic provided still seems pretty stable. Do I have dodgy internet?

What do you think? Thanks in advance!

[imteamleader]

Quick update.

I have 6 miners running now for over 24 hours with a pretty even hash rate. I am also running a couple of other spread around the house to see how they run. Everything is running fine.

So I'm guessing the miners were overheating? Does this sound about right.

What kind of temps should I be aiming for, for the room and the miners themselves?

[Steamtyme]

Definitely I noticed your error code in the image under pg heading says 3.

Here is the link to the Avalon 6 wiki and it has all sorts of info on them

https://en.bitcoin.it/wiki/Avalon6

The codes are added together so you have error 1 and 2,
2 being to hot. And error 1 which is idle, because of the over temp.

You might have been running into the issue of the warm air circulating back to the miners, not sure bit you should be okay now that you have spread them out.

Side note please install a c02 monitor in your house don't want to wake up and hear about a dead BTC miner.

[lightfoot]

Wait, your room ambient temperature is 30c? That's hot, remember that efficiency of a fluid in cooling is based on the differential in temps. In other words, the hotter the inlet temp, the less efficient cooling you will get and the lower the performance.

Can you put them in 2 rooms? Open a window?

C

[imteamleader]

Definitely I noticed your error code in the image under pg heading says 3.

Here is the link to the Avalon 6 wiki and it has all sorts of info on them

https://en.bitcoin.it/wiki/Avalon6

The codes are added together so you have error 1 and 2,
2 being to hot. And error 1 which is idle, because of the over temp.

You might have been running into the issue of the warm air circulating back to the miners, not sure bit you should be okay now that you have spread them out.

Side note please install a c02 monitor in your house don't want to wake up and hear about a dead BTC miner.

Ok, I get it now, great link!

How long does the PG column keep the notification for? When I first set them up I wasn't expecting them to put out so much heat. Things got pretty toasty down there. Is there a way to reset so I can see new notifications. I tried resetting cgminer.

I do have smoke/co2's hardwired throughout the house. I'm really not looking to end up in the news, I do appreciate the consern.

Wait, your room ambient temperature is 30c? That's hot, remember that efficiency of a fluid in cooling is based on the differential in temps. In other words, the hotter the inlet temp, the less efficient cooling you will get and the lower the performance.

Can you put them in 2 rooms? Open a window?

C

Yeah, it was warm. It was the lack of air coming in. Its 20 degrees C in the middle of the rack right now. I have a large fan taking air out and another bringing it in (from a very drafty entrance lobby). Ideally I would run everything in the one room, but I will need to put a hole though the foundation to bring the air in. I am still pondering this over.

I have another 4 running in the kitchen of the basement, and its getting fairly warm down there. I've just started monitoring the temp.


How do people usually keep the temp down in a residential setting for multiple miners. I'm in Canada and its -10 out, god know what I will do in the summer!!

Does anyone have any links to set ups that they have built. I have searched on here and not found much.

[Steamtyme]

Hey glad it's working out for you, I'm not to sure how long the code stays on for, I've never run into a problem with them yet, just something I picked up through the forum.

There are a lot of different ideas people use to cool the miners, I'm currently setting up something along the lines you did, I'm running my 2 741's towards my furnace I take in the basement, with the fan running 24/7 it will help keep my place warm. Mind you I have a 100 year old house with a stone foundation basement lol; also in Canada.

Some people either build a hot/cold side miner room, where the miners pass through the separation wall. You blow intake air into the cold side and an exhaust fan on the warm side.

Others do away with the wall and have a heavy duty exhaust fan up high in the room, with an air intake along the floor to, while setting up the miners low to the ground as well.

If you hunt around the forum you will find a few different ideas here are a few links.

https://bitcointalk.org/index.php?topic=2312465.0
https://bitcointalk.org/index.php?topic=2350914.0

[lightfoot]

What I have found that is optimal is to take a row of (BFL Singles, A6's, Neptunes, Titans, whatever is square-ish) and line them up in a window with the sash holding them down. Point the fans outward in the summer and you have a whole house fan that is exhausting heat outside. In winter point fan inside and you get nice warm fresh air in your house.

Works. The key is never try to cool the air coming out of the miner, just get rid of it.

[imteamleader]

I originally tried heating but that fell flat. It was never warm enough, then I figured it was the cold air intake from outside puling too much cold in. I still plan you use some of the heat once I am happy how things are running.

I would love to see some pictures when you are done you set up!



I definatly need to get a better set up for summer, I may build a room in the garage, but we have a long winter ahead of us...

[fanatic26]

The PG column is not where you find the error codes. You need to look at the EC column.

Your temps are totally fine in the screenshots. The temp limits are as follows: 45c/80c/80c

Also, if the Avalon boards get under 60c they will start having more hardware errors and hash at a lower speed. They need to be in the range of 60-75c which yours are.

One strange thing. The 18 hour screenshot shows 57th. 3.5*12 = 42th. There is some reporting bug going on with your software. I have personally found that the older RPi images and MM firmware from 2015 is actually more reliable and stable.

[imteamleader]

The PG column is not where you find the error codes. You need to look at the EC column.

Your temps are totally fine in the screenshots. The temp limits are as follows: 45c/80c/80c

Also, if the Avalon boards get under 60c they will start having more hardware errors and hash at a lower speed. They need to be in the range of 60-75c which yours are.

One strange thing. The 18 hour screenshot shows 57th. 3.5*12 = 42th. There is some reporting bug going on with your software. I have personally found that the older RPi images and MM firmware from 2015 is actually more reliable and stable.

So you don't think its the temps that are the issue. Could it be back pressure from the manifold on the fans?

Everything has been running well as I split the miners into to set ups. With the main set up venting into manifold it was running fine. I added 1 last miner into the set up and the hash rate started dropping?! I removed this miner when things started to take a dive but they still dropped. I reset the power for the set up and it was fine again.

Last weekend I added a larger fan pulling are into the room. The room is very cool now. I tried adding the extra miner again and now things are running fine. I'm assuming that with the cooler temp (from 10 to 20C in the room) the fans are running at a lower speed and not causing any back pressure.

Now with another problem you point out. The room is now very cool, and my temps are below what you recommend. However everything us running nicely. Should I be overly worries about being to cold?

https://ibb.co/jSwJdR

The other set up is venting directly out of the basement kitchen window. This box has been down as low as zero degree C. The miners seem to be running fine though.

https://ibb.co/jB89k6

Is this too cold?

[fanatic26]

It looks like yo uar e right around the edge as far as the cooler temps go. It doesnt look like you are losing any hashrate from it yet so I wouldnt be too worried about it as long as things dont get any colder. Another thing you can do is change the fan settings and slow them down a bit if you think the cold is starting to have an effect.

[imteamleader]

Ok, I will keep an eye on them.

I intend to add a thermostat to control the intake fan when it gets colder. Its hovering around -8 right now but will be getting a lot colder soon, and we get drastic temperature fluctuation.