I need help about SLA battery charger, BQ24450,
I modified BQ24450EVM-691 to charge a SLA battery, 4V, 2AH. The charger works good after I changed several resistors. the fast charge current is 700 mA at 4.9V. and the taper/ floating charger current is 140ma at 4.6 Vdc.The power supply is 7.9Vdc to 10Vdc. To integrated the Red, Green LED as the charging status indicator. I make my PCB for the charger. the attached files are the schematic and the PCB layout. the resistors used on both boards are the same value, only the difference is the package and power.
What I surprised is the max charging current is just 668 to 670mA. The current just 683mA when 0.180ohm is replaced with 0.174 ohm.
Please help to analysis what caused the current drop, and how to fix it?
