When is a LiPo dead?

[Bad Raven]

Tried an experiment.

Had a 370mAh 3S Nano-Tech that had reached end life, would power a 130S Heli for about 20 seconds before sagging. Repetitive.

Decided I'd see how long at a low current drain it would last.

Have an indoor own design plane with the right connector that has a total of 24 LEDS, the 3 at time sticky strip type.  6 Green, 6 Red, in nav light position, 6 white up fin front, three white and three blue underside centre line rear. Has been flown in total darkness no moon and the light can show enough of the ground to land, very bright on a 3S also powering the motor etc via a "Y" lead.

Starting from the Heli "fail" voltage, it lasted over a week with all lights quite bright, then the first to stop was green, followed by blue, then white over several more days. Red still working brightly.

Wing is inset into foam, lacquered motor wiring, about the same lengths, so not variable volt drop. All connections are well soldered to a common plug.

After the bulk stopped working, there were several days where turning it off overnight meant they ALL lit again for some time when re-connected, initially hours.

Now, THREE weeks on, the six red LED are still visibly "on".  After several days left on 24 hrs, an overnight off period STILL recovered the pack enough to be bright for some time.

OK, its a silly game rather than science, but it brings home just how resiliant to complete draining (and therefore disposal safety) LiPo are.

My local council way back set up from your door battery disposal including LiPo. Despite this I salt water bath them outside for at least a couple of weeks before disposal. As by then the connectors are corroded I have never tested them.

Now I know they are much more resiliant than I thought!  (and that with only a little 370mAh)