BQ24650: Charging from small PV panel

Ryan.Bishop

Part Number: BQ24650

Hi,

We are gravitating towards the bq24650 charger because it may work well with our solar panel.

My main concern is that the bq24650 requires 25mA supply current while charging, I(AC). When our panel is not receiving full sun, the panel current may reduce to < 10mA, so if the charger eats up 25mA, then we get no charging at all.

Is it possible to make external changes to reduce I(AC), like using very low Qc mosfets for the DC/DC power stage?

Are there any other techniques to make this charger with a low current PV panel? Or is the problem unavoidable?

Regards,
Ryan Bishop

over 7 years ago

0 Jing Zou over 7 years ago

TI__Mastermind 20570 points

Unfortunately, the 25 mA current is the current into VCC pin which is the supply current inside the bq24650. It does not take in the IQ of the external MOSFETs.
What is the panel output voltage and what is the battery charge voltage? Typically when the panel output voltage also decreases when it is not receiving full sun.

0 Ryan.Bishop over 7 years ago in reply to Jing Zou

TI__Expert 3900 points

Hi Jing,

Thank you for the quick reply. The customer has shifted their focus to other TI chargers to avoid this supply current.

Regards,
Ryan B.

Power management

Power management forum

BQ24650: Charging from small PV panel