well it shuts down AUTO when there is no external power supply. I wired it in my car and it acts just like a cd player: on when car is on , off when car is off and it picks tight back up where it left off in teh song. I figure it is disregarding the internal battery completly unless you manually turn it on when its off. SO if you have your external power supply die it wants to shut off so would it save your recording like when the internal battery dies and it "wants" to sht off.
I think i need to expieriment more...i haven't wired up my external batter yet for it just used it in car...in fact havent even tried recoding. i will today and let you know.
dan