Please bear with me. I'm pulling the pertinent stuff out of your word wall. Head butt me again if you feel the need. (It's OK. That helmet has hit me in the head so many times, I don't' even feel it anymore) If it's hot, the batts need lots of cooling, otherwise they will fail. You store your batteries in a fridge, to keep them healthy.
Don't fly until the ESC cuts out. Aaand. Thirty-five percent warning on the bat. Which means, I won't fly until anything cuts out. Got it.
It seems
@mayan and I share a similar climate at times. My minimum ambient is around 10 degrees Celcius. There is a need to keep batteries from freezing or getting to cold in colder climates but here the battle is against the heat damage to LiPo batteries.
After analyzing cell failures in a range of battery packs it showed a trend to the inner cells failing first or prematurely. A bit of temperature probe work showed that the temperature of the inner cells was highest in use and in charging Since i have undertaken my process for battery management the failure pattern or history has shown a marked drop in puffing batteries and a longer general life. This is coupled with a more even spread of cell failures such that the inner cell failure rate had dropped from around 90% to about 40%.
My average temperature profile on an average flying day is from around 10 Degrees Celsius at the start of the flight to around 45 Degrees on landing. The reason for the investigation into battery operating temperature was that I lost almost all of my flight batteries on a single flying day during a 50 degree Celsius heatwave and half of them were not even used.
Be gentle on your batteries and they will last years but treat them poorly and they could last only minutes.
We all have different climates and different flying aircraft and styles. I am just telling others what works for me in my climate from my own experience and measurements. I am sure others will have their own tricks and methods. I am not telling others that they are wrong but rather that we are different. Mind you i do have a couple of converts at my local club especially among those who run expensive 6S batteries in their EDFs.
@buzzbomb I try my best to keep the batteries, (each and every cell), at all times less than 50 degrees Celcius. I normally get discharge amounts of between 80 and 90% based upon what the charger puts into the batteries after flight and cooling. Generally you are correct in what you have reasoned out from the "WALL". I tend to over explain sometimes and under explain at others.
My idea behind the refrigeration came directly from cell temperature measurements. In the 'fridge the cell temps are eventually identical. On the way to the field the outer cells rise in temperature quicker than the internal cells. In flight the inner cells heat more rapidly but from a lower initial temperature and the cell temp still ends up higher than the outer cells but by a far lesser amount than before.
Temperature effects are known on cell performance but the temperature of the cells is anything but stable in flight and charging. That is why I still say that each individual should do some work and determine for themselves what works for them!
Most newbies need only worry about over-discharging their batteries until they are experienced enough to put the myriad of crashes behind them. At that stage they will suddenly find that battery replacement can become a significant expense and then they should find out what reduces their expenditure to a reasonable level.
Just (My thousand words on), what works for me)
have fun!
