I'm trying to charge a 18V/3Ah NiMh battery (15 cells x 1.2V) with the BQ2004E component.
So I have studied the BQ2004 datasheet and their switch-mode developpement system to adapt it to my specific case.
I tied TM1&TM2 to GND for selecting a C/4 charge. My Rsns is a 300mΩ/5W (Icharge = 0.225/0.3 = 0.75A = 3000/4).
I tied INH and VSEL to Vcc for choosing a PVD termination. I selected the number of cells with N = (780/120 + 1)*2 = 15 cells.
A 10kΩ NTC thermistor is placed on the TEMP connector.
So here is my circuit. View attachment 39643
It seems to work, when I connect my DC Alim (30V/6A) it goes in "Fast-charge pending" mode for any seconds, then goes in "Fast-charge" mode. But the "Charge complete" mode comes very early (about 5-10 minutes whatever it's initial charge). I've no more that 18.6V at the terminals of battery after charging.
I'm very newbie and don't know how to find where could be the problem.
Can you see anything wrong on my circuit and could you help me to make tests to highlight the issue ?
Thanks very much for your help
I am also sufferring from the same problem. i want to charge NiMH and Nicd battery of 9.8Ah and 4.4Ah respectively. Both are of 10 number of cells.