Standart m365 charger, charges the batteries to 4.2 volts (full charge). To prolong battery life it is possible to lower output voltage to 40.9 volt just with a screwdriver. It is the maximum lowest that i find the component allows. You need to open the charger case and find that screw. In this YouTube video you could see the screw
at 3:26. Be careful not to touch metal parts if you are doing the change when charger is connected to plug. I measured the voltage with a multimeter probe from round connector tips. (Not from inside like the video). Be careful not to short-circuit when measuring with multimeter probes (charger tips are close). I found it ieasy to close the charger case with duct tape at the end rather than using super glue or hot glue like in the video.
With 40.9 volt, when charger shows green light, m365 program shows 40.65 volt battery, %95. Which i think iş a sweet spot between battery life and capacity.
I will modify a friends charger than i will add photos also.
https://batteryuniversity.com/learn/art ... _batteries
Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles.