BQ24650: charging issue

Cherry Zhou

Part Number: BQ24650

Hi team,

Here's an issue from the customer may need your help:

Using the BQ24650 as a solar panel charging circuit, it's able to charge and function normally. The battery is unplugged at night, the load and solar panel are connected, and the next day, when the battery is plugged in, the BQ24650 board is unable to charge the lithium battery in full sunlight. The solar panel must be unplugged before it can function properly.

The customer would like to know what's the reason for that. Could you help look into this case? Thanks.

Best Regards,

Cherry

over 3 years ago

0 Michael Emanuel35 over 3 years ago

TI__Mastermind 41785 points

Dear Cherry,

What is the solar panel voltage in the morning when it cannot charge the battery? Also, why is the battery being unplugged at night? Can you send a schematic as well?

Thanks,

Mike Emanuel

0 Cherry Zhou over 3 years ago in reply to Michael Emanuel35

TI__Mastermind 22235 points

Dear Mike,

Thanks for your help!

Michael Emanuel35 said:
What is the solar panel voltage in the morning when it cannot charge the battery?

Around 22V.

Michael Emanuel35 said:
Also, why is the battery being unplugged at night?

For safety reasons.

Michael Emanuel35 said:
Can you send a schematic as well?

Please see the link below:

https://e2echina.ti.com/cfs-file/__key/communityserver-discussions-components-files/24/3323.chargeSchematic-Prints.pdf

Thanks and regards,

Cherry

0 Michael Emanuel35 over 3 years ago in reply to Cherry Zhou

TI__Mastermind 41785 points

Dear Cherry,

What is the value of MPPSET at this time?

Thanks,

Mike Emanuel

0 Cherry Zhou over 3 years ago in reply to Michael Emanuel35

TI__Mastermind 22235 points

Dear Mike,

Michael Emanuel35 said:
What is the value of MPPSET at this time?

It's 1.6V.

Thanks,

Cherry

0 Michael Emanuel35 over 3 years ago in reply to Cherry Zhou

TI__Mastermind 41785 points

Dear Cherry,

Can you try toggling the CE net you have for Q4 after plugging in the battery and see if that makes any difference?

Also, for more information can you try different combinations of what you leave plugged in and what you do not?

Thanks,

Mike Emanuel

Please click "Resolved" if this answered your question.

0 Cherry Zhou over 3 years ago in reply to Michael Emanuel35

TI__Mastermind 22235 points

Dear Mike,

Thanks and they've done some attempts:

1. Once the battery is plugged in, switch to Q4 and charging recovered.

2. after plugging in the battery, the charge can be restored by removing the load.

May I know what this might be caused?

Thanks and regards,

Cherry

0 Michael Emanuel35 over 3 years ago in reply to Cherry Zhou

TI__Mastermind 41785 points

Dear Cherry,

Glad that works!

I need some more information to answer your question however as it relates to the setup.

How is the load connected and how much power does it draw (voltage and current)?

What is the SRN voltage when charging will not happen in the original case, in item 1 above, and in item 2 above?

In addition, what are the STATx LEDs and MPPSET doing in all cases asked above?'

Thanks,

Mike Emanuel

Please click "Resolved" if this answered your question.

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BQ24650: charging issue