Not really a beginner, but I consider this a beginners question.
What is the actual "danger zone" when it comes to cell voltages for LiPo batteries? I have heard 2.5V, 3.0V, 3.3V and 3.4V as the "don't ever go below, or your battery is ruined..." Seems that 3.0V is the most frequent that i have seen.
Also I would assume that this limit is "while loaded". But someone say that it is the "no load" voltage that is important...
My initial question is as stated, what is the voltage one should never be below.
A followup question is, is there any ways to check if the battery is ruined? I.e. can one determine anything from its voltage drop with a given amperage? (i.e. if i discharge it in the charger with 5A, can i see anything on the voltages that would indicate ruined battery?)