# How to find how many Amperes does a equipment use? [closed]

In the specification of this miner https://www.asicminervalue.com/miners/bitmain/antminer-s9j-14-5th it says it uses 1350W power with 12V electricity. I like to know how can I find how many Amperes this machine uses?

In general I like to know with a electricity supply around 380V and 150A how many of these machines can be run?

• Hint: Watts = Volts x Amps – dim lost faith in SE Aug 30 '19 at 8:37
• As P=VI, P=1350, V=12, that means that 1350/12 = I, so total current is 112.5A. Which is quite a bit. You need a good chunky wire to deliver that kind of current without significant heating of wire and voltage drops. – Puffafish Aug 30 '19 at 8:37
• @Puffafish: Shouldn't 1350 be divided by 3600? – user3486308 Aug 30 '19 at 8:40
• If you have 100 machines, they need 135000 W. If you supply them from 360 V you need a converter stepping down from 360 V to 12 V. The converter input current will be 135000/360 = 375 A and the converter output current will be 30 times larger (minus converter losses) which is 11.25 kA. And this is, as written before, 112.5 A per machine. – UweD Aug 30 '19 at 8:46
• Also you may want to have a look at the graph to the right of the unit on the page you linked to. Apparently these units can't run at a profit unless you're getting your electricity at a very low rate. And if you're stepping it down, you will need to pay to the energy into the system (including that which is wasted in the conversion down to 12V) and energy used to cool the system. – Puffafish Aug 30 '19 at 8:52