I am using the BQ25890 charger to fast charge a 1S 2P Li Polymer battery that is 7.2Ah in capacity. I have two questions:
1. I would like to understand if there are any special USB power adapters (wall warts) that incorporate the TI Maxcharge algorithm so the handshake can be completed without hiccup. Currently I am using a QC 3.0 Qualcomm quick charge adapter and the charger reads it as a "HVDCP" and sets input current limit at 1.5A (REG00[0:5]). I want to set the input current limit at 3.25A (USB DCP) so that I can perform autonomous charging cycles.
2. I would like to know if the charge time is adjusted based on the battery capacity because I see that charging cycle takes forever to complete. Theoretically, a 7.2Ah at 3.5A charge rate should be completely charged within 3 hours time, but I see the charge time is around 4 hours. Even if I plug in a 3.8V battery (about 50% charged, I see that the charge time is still more than 3 hours) The current seems to drop ever so slowly. Is it possible that the software driver is programmed to do such a thing? Or the resistance of my design is so much? The CC-CV transition seems to occur quicker than expected.
Please enlighten me! Thanks,