BQ76952: 4S battery goes into sleep after a complete discharge even though Power Config, SLEEP (Bit 8) was set to 0

Mo Mizzi

Part Number: BQ76952
Other Parts Discussed in Thread: EV2400

Tool/software:

Good morning,

We designed a 4S battery for our controllers using the BQ76952. I'm attaching the config file set by the EV2400.

We are not interested in the SLEEP mode, and have set the SLEEP (Bit 8) in the Power Config Register to be 0. However, we are noticing the 4S battery would go into SLEEP mode when it's completely discharged. It doesn't allow for charging.

We want our users to be able to charge the battery once it's goes dead.

I'm also attaching the config file after it goes into SLEEP mode and automatically changes the SLEEP (Bit 8) in the Power Config to 1. How can we avoid this situation? It's holding us from shipping our unit out.

BQ76952_4S_8A_NoSleep_R1.gg.csv

The config file below was exported after it goes into SLEEP mode (when completely discharged).

goingToSleepAfterCompleteDrain.gg.csv

2 months ago

0 Mo Mizzi 2 months ago

Intellectual 290 points

Hi, Alexis_H, just wanted to see if you had any insight on this issue. Thank you.

You had helped quite a bit in the past when designing this BMS initially. Appreciate all your help!

0 Mo Mizzi 2 months ago

Intellectual 290 points

Good afternoon,

Just following up to see if anyone has any insights on this issue. We have another 48V battery that we designed using the BQ76952 and it's running into the same issue. We have to order more batteries for our customers, but without finalizing the BQ76952 BMS, we cannot proceed.

Unfortunately, it's holding us.

Thank you.

0 Mo Mizzi 2 months ago in reply to Mo Mizzi

Intellectual 290 points

Good morning TI team,

Just following up to see if anyone had a chance to look into this issue?

0 Mo Mizzi 2 months ago in reply to Mo Mizzi

Intellectual 290 points

Good afternoon,

Just checking to see if there's a basic start up guide to use the BQ studio with the BQ76952

0 Mo Mizzi 2 months ago in reply to Mo Mizzi

Intellectual 290 points

Just bubbling this up, to see if anyone has any feedback.

0 Gavin Long 1 month ago

TI__Prodigy 740 points

Hi Mo,

What voltage is the Battery falling to when you say completely discharged? Is this 0V?

When comparing your config settings before and after complete drain, it seems like all the settings are returning to default values including: Power Config, REG12 config, REG0 config, TS3 config, Vcell Mode, Protections A&B, and a few others.
This seems to imply that a POR is occurring, where digital is getting reset due to low voltage from REG18. This would cause the register settings to get reset to default values, including the SLEEP setting.

Power management

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BQ76952: 4S battery goes into sleep after a complete discharge even though Power Config, SLEEP (Bit 8) was set to 0