BQ24450: 12 V battery charger solution from 100W solar panel

jameer hydrabade

Part Number: BQ24450
Other Parts Discussed in Thread: BQ24650, BQ25713

We want to design the solar charger circuit .Please suggest us the best PMIC solution to go for the design along with the design solution . We have a 12V 42Ah SMF lead acid battry and a 100W solar panel.So kindly suggest us the best PMIC for the solar charging and We also need your help for the designing.Please reply soon.

over 4 years ago

0 Jeff F over 4 years ago

TI__Guru**** 150335 points

Jameer,

What is the open circuit voltage of the 100W panel?

Regards,

Jeff

0 jameer hydrabade over 4 years ago in reply to Jeff F

Prodigy 60 points

The open circuit voltage of solar panel is about 21 volt , you can consider max 26V for design consideration.

0 Jeff F over 4 years ago in reply to jameer hydrabade

TI__Guru**** 150335 points

Jameer,

The power loss across the pass FET of the BQ24450 linear charge is (21V-12V)*Ichrg. I think the pass FET will get very hot and be difficult to heat sink. I recommend you move to a switching charger like BQ24650. Please review the app notes below regarding using this LiIon charger to charge Lead Acid.

https://www.ti.com/lit/an/slua586a/slua586a.pdf

Regards,

Jeff

0 jameer hydrabade over 4 years ago in reply to Jeff F

Prodigy 60 points

I also want to read the solar voltage and battery voltage, how it can be done? If possible I want to read the current of battery charging.

0 Jeff F over 4 years ago in reply to jameer hydrabade

TI__Guru**** 150335 points

Jameer,

To read the voltages and currents, you would need a host processor with ADC. Or you could change to BQ25713 which has integrated ADC. You would use the host processor to communicate with the charger over I2C.

Regards,

Jeff

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BQ24450: 12 V battery charger solution from 100W solar panel