For safety sake you should always charge them right before you use them and in a controlled environment. i.e. charge and stay in the same area, don't walk away and do something else where you cannot keep an eye on them.
For best performance: Warm the cells to at minimum 80F before charging, start the charging process and continue warming the cells to 100DegF. Optimally the cells go into the boat at 100-110F. The cells will hold their voltage much better and you do much less damage to the cells.
If you must charge them before you get to the pond, warm them to 80F at home while charging and keep them above 60F in transport. At the lake warm them up to 100DegF and run them.
After you run them, let the cells cool below 90F and check their voltage. If above 3.8v/cell put them on a storage mode setting on your charger or invest in a ISDT discharger
https://a.co/d/5eKAgpY . If they are between 3.7 and 3.8v/cell just check their balance cell to cell and put them away. If they are below 3.7v/cell put them back on the charger in a storage mode.
