BQ24450: 24v Lead Acid resistor values

Martin Keen

Part Number: BQ24450
Other Parts Discussed in Thread: BQ24650

Hi,

In relation to this post here: (+) BQ24450: BQ24450 24V Lead Acid Battery charger circuit Resistors Value - Power management forum - Power management - TI E2E support forums

There was a private message sent with resistor values for a 24v charger (2x 12v lead acid batteries).

I also would like to use this chip for charging 2x12v lead acid batteries using similar criteria.

My input voltage will be equal to the maximum charging voltage around 28.8v. Can this chip charge at these levels? The spec cays 20v is maximum charge voltage?

Float voltage will be around 27.4v.

Charge current max only needs to be 1.5A.

Thank you.

Martin.

over 4 years ago

0 Nick Brylski over 4 years ago

TI__Mastermind 19195 points

Hello Martin,

Yes this device can support your use case, please go by the datasheet which states the device is up to 40V tolerant. I will check what values the previous customer was using.

Thanks,

Nick

0 Martin Keen over 4 years ago in reply to Nick Brylski

Prodigy 10 points

Thank you for clarifying the charge voltage, I look forward to the values.

Regards,

Martin.

0 Nick Brylski over 4 years ago in reply to Martin Keen

TI__Mastermind 19195 points

Hi Martin,

You can refer to this excel spreadsheet with a 24V example calc.bq24450_calc.xlsx

We also have another part you can consider, bq24650. Here is an app note on configuring this one for lead acid: https://www.ti.com/lit/an/slva437a/slva437a.pdf

Best regards,

Nick

0 Martin Keen over 4 years ago in reply to Nick Brylski

Prodigy 10 points

Thanks Nick, I'll give it a go.