# How long a capacitator can power an Nano Every

Dear all,

I build a circuit to monitor a PSU and planned to store the last setting of the PSU is off by powering the arduino with a capacitor of 16V with 2200uf as buffer. The voltage is on 12V and directly connected to the regulator of the nano every.

The LED goes of after 1-2 seconds. Is this fine or did I have a fault in my circuit?

Regards, Nils

Rough estimate: energy in cap = 0.5*2200e-6*12*12 = 0.1584 J Energy used by arduino assuming 5V @ 20mA = 0.1J per second. So a couple of seconds sounds about right.

There's also a "SuperCapacitor Calculator" from one of the manufacturers. Only the top part is relevant to your question - it takes a working voltage (12V), a minimum output voltage (say 5.5V) the current requirement (I said 20mA), and the time. It says 1s should require about 3000uF...

Mhh, it goes directly off in my oppinon. Thats an interessting information so I will dive in and check if I build everything correctly. Thanks a lot.

But also I thought it will work for 10 seconds or longer...beginner fault. :-)

Cheers, Nils

The energy consumption of the Arduino is dynamic and depends on what peripherals you are using. You can detect the voltage being switched off and then shut down everything you do not need to make the energy in your cap last longer.

Have a look into the datasheet and circuit diagram for your Arduino to find out what order you need to switch off stuff. I/O pins (output) is usually one of the biggest factors, but high-speed peripherals like radios, Ethernet and so on can use lots of power too.