Battery use prediction with INA219

[fenghuang]

I've read quite a few threads loosely on this topic and have failed to find a satisfactory answer.

I have a project (Nano + peripherals) for which the power consumption will vary WRT time depending on external factors, and I need to work out what battery to spec for it.
So I'd like to log the power consumption.

I've come across the INA219 current sensor which looks like it will help.

Am I right in thinking that, if an INA219 is connected between the battery and the Vin of my main project, I can use a second Arduino to log the current drawn by the first?

[sherzaad]

@fenghuang

I have a project (Nano + peripherals) for which the power consumption will vary WRT time depending on external factors, and I need to work out what battery to spec for it.
So I'd like to log the power consumption.

@fenghuang

Am I right in thinking that, if an INA219 is connected between the battery and the Vin

that's what I would do, yes!

@fenghuang

I can use a second Arduino to log the current drawn by the first?

you could indeed or just use you Nano (assuming you have available pins to so) to do the logging!

hope that helps....

[J-M-L]

@sherzaad

or just use you Nano (assuming you have available pins to so) to do the logging

that logging activity (assuming CPU time, SD card access, powering the INA219) would draw power and thus you would get biased results. If sleep is also being used on the Nano then it would not record what's going on during that time

So I think it's a better idea to use a separate device

[fenghuang]

Thanks both.
I wouldn't have thought of using the same device, and in different circumstances that might be useful, but as J-M-L says, as I'm planning to implement further down the line, it's worth using my spare Uno.