Battery monitoring - ever tried AN1072?

[amgen]

for low battery draw, use high value r's and wait 5RC , that's 5 time constants between readings which allows 1 micro farad cap to charge to full divider value. That's 180K times 1X10to minus 6 which is about .2 seconds. The 1 micro farad is many times the cap value in the pic so it is an accurate reflection of the voltage and high r's draw micro amps from battery...... no switching on/off stuff