bq25505

Dan Friel

Other Parts Discussed in Thread: BQ25505

Trying to charge NiMH cells with the bq25505. Using four (4) NiMH cells in series requires charging a bit higher than the 5.5V maximum of the part so I'm worried about long-term damage to the part. Has anyone used the 25505 (or other parts in the family) to charge NiMH cells? (

Also, since I'm using 4 NiMH cells, I have 4 alkaline cells for the backup power source which is switched in when the NiMH cells are depleted. Four new Alkaline cells can exceed 6V total so is that another problem I need to consider?)

over 10 years ago

0 Jing Zou over 10 years ago

TI__Mastermind 20570 points

Correct. The maximum battery regulating voltage is 5.5V. In your case, your batteries might not be fully charged. In long term, it is not good for your battery health.

VBAT_PRI voltage should not exeed the maximum rating as well. You can add an zener to clamp the VBAT_PRI voltage down to 5.5V.

0 FRANCOIS DION over 9 years ago in reply to Jing Zou

Prodigy 135 points

Hi, I am interested by the topic and I would like to know exactly what kind of problems it can cause to the battery?

thanks!

0 FRANCOIS DION over 9 years ago in reply to Jing Zou

Prodigy 135 points

Also, I would like to know if it can do damage to BQ25505?

thanks!

0 Gautham over 9 years ago in reply to FRANCOIS DION

TI__Genius 12485 points

Francois,

This article has some information on charging batteries at different votlages.(Figure 5)

Please check with your battery manufacturer for information on using different charge voltages of the batteries as well.

Regards,

Gautham

Power management

Power management forum

bq25505