Q: bq2415x - Will not power-up and charge without I2C communication

The battery will not charge and it was noticed that the electronic switch to connect the battery was closed after the bq24156 was powered up.  is this the problem.

A: Re: bq2415x - Will not power-up and charge without I2C communication

Check the sequencing of the FETs versus the power-up.  If the battery is not connected before the IC comes up and tries to charge, then charging will not take place. 

If the battery is present at the power up of the charger the part will start charge at the default settings until the watch dog timer expires.  For the desired charge parameters, communication via I2C is needed to program the IC and keep the watch dog timer from expiring and returning to the default settings.