Same battery voltage reading, 3700mV, even though it charges


Hi all,
I am charging a 650mAh LiIon battery through a Q2400 module from a switching current source of 800mA, maximum voltage 4.8 Volts. I set the charging parameters as follows:
I’m starting the charging process as bellow:
Although the battery is charging correctly and its voltage rises slowly and with pulses, the AT+WBCM=2 always reports 3700 mVolts, even though the battery has reached 4200 mVolts. The battery is connected directly to the Vbatt pins of the GSM module using a short cable (3cm) so there is no issue of the cable resistance. Can anyone figure out what is wrong? I’ve tried another GSM module (Q2406B) and another battery with the same results.


Dear Orytel,

I had this experience too.
It happens in Q240X and Q24 series wireless module with old firmware.
Check with your local distributor for the latest firmware update.


I am having the opposite problem on the Q2686. I am battery charging as well, and the battery level is reported always 300mV too high, then occasionally, it returns to the correct voltage. Even when the charger is disabled, the battery level is still read incorrectly. Any ideas anyone?


Thanks hslai

Do you know which is the latest firmware version for the Q2400 module and which for the Q2406? The ones I’m using now have the 3.50a version.