While wandering around the "Battery University" site I came across a posting titled, "BU-808: How to Prolong Lithium-based Batteries" A link to the article is posted below
https://batteryuniversity.com/article/bu-808-how-to-prolong-lithium-based-batteriesKEY INFORMATION in this article is that a peak charge is a stressful event for a Lipo cell that defines its cycle life. Knowing this leads to a dirt simple method to greatly extend the lifetime charge cycles for our Lipos. All we have to do is to charge them to a slightly lower peak voltage. What really caught my eye is that lowering the peak charge by only .1V per cell can DOUBLE the lifetime charge cycles for a Lipo pack! The table showing the effect of lower peak voltage and battery life is copied and shown below. (please forgive the miss aligned columns)
CHARGE LEVEL* DISCHARGE CYCLES AVAILABLE STORED ENERGY **
(V/CELL) [4.30] [150–250] [110–115%]
4.25 200–350 105–110%
4.20 300–500 100% 4.15 400–700 90–95%
4.10 600–1,000 85–90% 4.05 850–1,500 80–85%
4.00 1,200–2,000 70–75%
3.90 2,400–4,000 60–65%
3.80 See note 35–40%
3.70 See note 30% and less
Table 4: Discharge cycles and capacity as a function of charge voltage limit
I have only started dabbling with this approach, so my results are limited - but promising. For example I have a Classic airplane I am flying we 3Sx3500 packs. When peaked to 12.6V (4.2V/cell) it uses around 2665 mah per flight. I recently flew it with the packs charged to 12.3V (4.1V/cell) and usage (predictably) increased by 96mah to 2761 mah. However, end of flight voltage of the pack was 11.1V which is of course nominal for a 3S pack. That sounds like nearly zero added stress on the battery due to a too-low voltage state. I also use these packs another lightweight airplane that only uses 1900 mah per flight - the lower voltage charge will be a no-brainer there!
I was able to set the peak charging voltage to 4.1 by a dirt simple means; when I set my chargers to Li-Ion (instead of Li-Poly) the charging peak changes to 4.1V/cell instead of 4.2V/cell (I like simple!)
Most folks I have talked to are flying with some excess in their battery capacity - it only makes sense for electric (or glow for that matter) set-ups to NOT fly right at their limits. Since we fly with less than peak power for our power systems, always fly the same speeds and duration we can very accurately repeat our battery usage and determine if lower peak voltage will work for us. If that applies to your case, then consider taking advantage of the reduced peak charging strategy to reduce the stress and extend the life of your lipos.