I tried Grade mode for an XTAR 16340 3.6V Li-ion 850mAh cell again and it continued to repeat the Charge-Discharge-Charge cycle.
The current cut out for a minute when the voltage reached 4.212V at the end of the first Charge-Discharge-Charge cycle (shortly after 6 hours). The VX4 then started discharging again at around 290mA. I wonder if the protection circuit of the cell caused the cut out.
Let’s see if the same thing happens with an XTAR 18650 3.6V Li-ion 4000mAh cell…
I tried Grade mode for an XTAR 18650 3.6V Li-ion 4000mAh cell and it continued to repeat the Charge-Discharge-Charge cycle.
The current cut out for a minute when the voltage reached 4.213V at the end of the first Charge-Discharge-Charge cycle (shortly after 12 hours). The VX4 then started discharging again at around 290mA.
EDIT:
I tried Grade mode again and it worked properly.
For my tests I cleaned all contacts with contact cleaner and squeezed the terminals tightly for the first few seconds during IR measurement. Usually it improved the charging rate.
I have the VC4SL, also for me it´s also annoying to select 1A and it charges at 500 or 250mA.
I can charge in another charger these cells with 1A or more without getting hot temperatures, and it concerns a lot of cells.
Maybe the general problem with this kind of Xtar charger is after plugged in it select the highest current available, that means 3A with one cell if a QC-power supply is used.
Same with the VX4?
Maybe Xtar should this charger call the VX4 an automatic charger which can charge on a very good day with max. 3A .
I´m still fan of the Vapcell S4+ because it let the user choose if he want to use manual settings or automatic mode.
That´ts what I mean, using 1/6 of selected current is really bad, fast charger? No!
Did you can charge this cell in another fast charger with 3A?
The VX4 always shows the selected current instead of real current?
That means Xtar thinks we all dumb?
Not sure if a non-advanced user will buy a charger in this price class, it´s more for other users. But these users want a charger with more possibilities.
I agree with Johnny-Bravo, for me the VX4 is also more an automatic charger.
The Vapcell have a good solution, Also the LiitoKala Lii-600 which is in automatic mode after plugged in, switch to manual with one button pushed.
If Xtar is concerned about the user mabye the better solution is a temperature protection or something.
I’m trying to charge an XTAR 26650 in a Vapcell S4+.
AUTO mode has selected 1A with a 65 mOhm IR and 3.3V.
I took the cell out, put it in another channel, and AUTO mode has selected 1.5A with 54 mOhm and 3.6V.
I took the cell out again, put in in another channel, and I was able to select 500mA/1000mA/1500mA/2000mA in MANUAL mode with an IR of 60 mOhm.
The Vapcell S4+ is also imposing a limit to what current can be selected in MANUAL mode based on the internal resistance.
I took the cell out again, put in in another channel, and I was able to select 500mA/1000mA/1500mA/2000mA/2500mA/3000mA in MANUAL mode with an IR of 39 mOhm and 3.8V.
I’ll try to charge the XTAR 26650 in the XTAR VX4 again from a higher voltage (e.g. 3.85V). Hopefully the IR is lower and the VX4 allows 3A charging.
I’m not really using the VX4 how I would normally use a charger when I do these tests.
I normally “top up” a cell from 3.6V when it has been sitting in storage or from 4V if it is in a flashlight. I rarely have a cell that’s under 3.3V unless I’ve been using Turbo on a flashlight.
If you’re topping up a cell, then you should be able to select a higher current like 3A as long as the internal resistance of the cell is low and the charging rate is below what a manufacturer of a cell recommends as a maximum.
It would be nice if the XTAR VX4 could continuously check the IR and increase the charging current up to the maximum selected charging current. E.g. Start at 500mA and increase to 3A instead of being stuck at 500mA when I have selected 3000mA.
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