It’s worse than storing it in the ideal zone - between 3.6 and 4.0 volts (% means nothing if we’re getting technical as there is an interpretation later in software). Constantly at 4.2 is bad, dropping below 3.0 is very very bad, and going to ~2.7(iirc) is simply murder. I have a telemetry module in a rocket which doors not have a low voltage cut off and every time I’ve left it on at least one cell in the lipo is permanently damaged.

In the telemetry case, it’s designed to run absolutely a long s as possible because the cost of a (interchangeable) battery is small compared to the cost of the rocket and telemetry payload.

I’m not a battery expert, but I’ve left lipos in computers and phones on chargers for years without substantial/excessive deterioration relative to their number of charge/discharge cycles; my experience with the telemetry makes me more wary of full discharge as a cell damage condition (not a direct analog as the deck certainly shuts down before lipo cell death)

—-I should point out that I’m not terribly worried about battery damage - that’s a red herring. I’m just pissed when I grab my deck and its battery is dead and I was hoping to squeeze in a quick game. :-)