ACS711 and ACS715

Hi all,
hoping someone here messed with these things…

what im trying to do is detect when a battery charger is connected… the battery charger doesnt output any power till it
sees a battery… it seems to pulse its output and monitor the battery on its off cycle
so… what i really need to know is if NO current flowing say for 1sec, battery charger is off/disconnected
now its possible current is flowing back into charger, im assuming the 715 will let current flow in BOTH directions
but only be able to provide output > 500ma when its one way, which works for me

Q, whats the minimum current i can read? 5ma is the current that prob flows due to…
when the battery is connected to my board, im actually connected through a 4.7k ohm resistor to the batteries
this turns on the charger, then i detect current, and turn on a relay, directly connecting the charger to batteries
i need to be able to see the charger be disconnected…
and turn of my main relay, and then the 4.7k is back in place for the next time


Hi, Mitch.

It isn’t good to assume the 715 can handle much reverse current. However, I just tested a unit we have here up to -5A, and the output was at about 360mV. Between 0 and -5A, it never went above 500mV.

The minimum current you can read depends on the noise of the sensor, the sensitivity of the sensor, the properties of your ADC, and any other noise in your system. I do not think you will be able to get a 5mA reading with any of these current sensors. Even on the +/-5V ACS714, there is about 100mA of noise.

- Ryan

ok, if thats true, i need another solution

i need to see 5ma

really i only technically need to know if NO current flowing

as for reverse current, so if i put current in reverse on a 715, does it damage it?
i would hope that it just passes though in either direction…
just doesnt give valid voltage output


I do not think it damages it. -5A definitely did not damage it, and I would expect that to continue within the current rating of that conductor.

- Ryan