battery vs inteval

[koos147]

not an actual issue. more a future request.

when the board runs on battery (or solar) you have to choose between outage. or long intervals.
when the battery runs empty the board will never get enough power for a strong transfer.
can we make the interval variable with the battery level.

the board register the battery minus 3 volt. (so we have a scale for 0v > 1.5v )
i suggest the follow calculations
1.6-[volt] *3000 seconds
this give us a scale from 5 to 75 minutes interval.
when usb power is present the board will always use the 5 minutes interval. but when external power is lost the board will use its power wisely.

i expect this would't be to hard to implement but the code of this tracker is above my level. :)