Bitcoin Forum

My apartment only has 120v 20 amps circuits. Is it possible to convert them to 220v? It is an unit within a 20 story building.

Well, firstly, remember that's (20x120) 2400W maximum (and not a good idea to run anything at the limit all day long)

Also check what cables are rated in your area e.g. in america they are typically only 15A and will get hot running them even at 15A all day.
Of course, if you change it to 220V the lead current drops to almost half.

Lastly, current bitcoin miners are well above 2400W, so you'll need to buy previous gen or older 2nd hand miners.

I think you can run a miner at 120v but you couldn't run all of your hashboard only 1 or 2 hashboard that I know success mining on 120v.

So you would need a step-up transformer to mine at 240v but I don't know if you could run at 24/7 I believe the lifespan of the step-up transformer is very short compared to installing a 220v in your house you can hire a professional electrician if you want a 220v in your house it would be a better option than using a step-up transformer.

You need a tester, check in your panel if you have more than one phase/hot coming in, if you do, measure AC voltage using the two hots.

120v is always less efficient (more wire resistance). And you generally don't want to be running more than 8A for example with the APW3++ (rated 10A) meaning 960W.

And yes, those PSUs were made in China for China voltage (230v) barely tested with "foreign wasteful voltages"), so if they say 10A is max @ 230V, don't expect halving the voltage would make the inside wiring magically support twice the amps. The PSU sticker usually tells you but some psus can't even accept that low range.

Now if you get 240v from two hots or two phases (208v) then that is good.

Maybe an S9 with two boards or 3 boards underclocked to below 1000w using APW7 PSU, but most if not all of the miners that came after that require 220v-240v and won't operate at 120v even without any hash boards installed.



A transformer is "supposedly" built to run 24/7, but you are right, most of these commercial transformers are shit, and a solid transformer will probably cost a ton, but that still might be cheaper than installing 220v, he just needs to check both options and see what works best.

If you believe Bitmain's own documentation, APW7 is even lower rated for 120V (Max 7A vs Max 10A for the APW3++). Perhaps it was never designed to work at the lower voltage range in the first place, but later they figured it could actually work a little with the same thin wires?

1365W+10% = 1502 which at 120V is 13A or 9A with two hashboards (See specs for the S9j 14.5).
In short, no, especially with the higher rated models.

You are welcome to do your own experiments, but using factory firmware with low voltage is risky as it doesn't limit power. In China they don't use this low voltage so its not an issue there. It is especially bad in Japan which has the world's lowest voltage (100V).