Adjust charging voltage as you like?

[Shenzhen XTAR]

If there is a charger with voltage increasing and decreasing mod, you can adjust the output voltage and charging current as you like, for example, increase the charging current to 4A to decrease charging time, what do you think of it?

 

[Carambrda]

1. Always put the safety first. A charger with an adjustable voltage cut-off can be confusing to the novice user so this could also be risky because the batteries can be overcharged to dangerous levels if the voltage cut-off setting isn't displayed very clearly on the charger and/or if the instructions in the user manual are explained too ambiguously. Charging an ultra-high capacity cell at 4A could also be dangerous, if the user does not know about battery specifications.
2. Decreasing the voltage cut-off a little bit below the standard cut-off can significantly extend the cycle life of batteries, similar to decreasing the charging current. Whereas keeping the standard, or default cut-off (equal to 4.2V for most of the cell types used for vaping) gives the most vaping time, or actual energy output. (And increasing the charging rate will sacrifice on cycle life expectancy of the cell, in exchange for faster charging.)
3. For some advanced users, having a user-adjustable voltage cut-off may offer certain benefits. For example, the LithiumWerks (formerly A123 Systems) ANR26650M1-B has a standard cut-off of 3.60V whereas most chargers either cannot support LiFePO4 cells or will overcharge them typically to 3.65V so, personally, I, like the option to be able to set it to 3.60V instead. (But not a lot of people still use these cells, as the energy density of LiFePO4 cells tends to be rather low compared to other, more popular battery chemistry types.) Also, with cell types that can be charged to 4.2V, mechanical mod users who are knowledgeable about coil builds may (sometimes) choose to not charge their batteries fully to 4.2V because this gives them the opportunity to decrease the power level to match their own personal preference about power. Else, to decrease the power they would then be forced to increase the resistance of their coils by designing different coils, which is not necessarily always a feasible thing for them to do. So, being able to adjust the voltage cut-off in small (0.01V) intervals on the charger is a nice feature, at least for me.
4. Faster charging causes more heat. Having too much heat decreases cycle life. This is why I avoid using the 4A charging capability. Instead, I usually stay at or somewhat below 1A charging. That is, except when I am using the aforementioned ANR26650M1-B, which is a true fast-charging cell, but I don't really use that very often.
5. Cycle life tends to be fairly difficult to measure or estimate. Over time, slowly the battery capacity degrades due to battery aging. The main factor that accelerates battery aging is battery temperature, but not a lot of battery chargers have battery surface temperature sensors at the bottom of the slots, and, the ones that do aren't closely accurate enough, or else they can't be programmed to decrease the charging current automatically to stay below the temperature level that the user wants to stay below. They offer some kind of internal overheat protection that will protect the charger, but they don't include things like cell cycle life monitoring or long-term analysis, and optimizations through comfortably user-adjustable profiles to control the charging speed.