BQ40Z60: Pre-charging after powerdown

Robert Ploeg

Prodigy 240 points

Part Number: BQ40Z60

Hi,

We've developed a 4S6P pack with the BQ40Z60.

Discharge stops at 2750mV / delay 5sec, based upon CUV

To preserve capacity after full discharge, we've set Power - Shutdown voltage @ 2750mV / delay 10sec

For charging we've set:

Pre-charge start voltage 2200mV

Charging voltage low 2900mV

Precharging current 250mA

Charging current low 1000mA

If the battery is left alone for a while after full discharge, the battery goes into shutdown. Leaving for a longer period will drop the voltage further.

The problem we've got is the BMS wakes up when a charger is connected but does not start charging at all.

over 4 years ago

0 Wyatt Keller over 4 years ago

TI__Guru** 105590 points

Hello Robert,

Can you provide the .gg file and a schematic of your system?

On page 56 of the TRM the flow chart to begin charging is outlined, have you verified all the conditions are met to begin charging?

TRM: www.ti.com/.../sluua04d.pdf

Sincerely,

Wyatt Keller

0 Robert Ploeg over 4 years ago in reply to Wyatt Keller

Prodigy 240 points

Hi Wyatt,

As far as we can see, the requirements are fullfilled.

Files attached.

Thanks,

Robprodu240_8-3-20.gg.gg.csv Battery Protection Powerbox V1.1_SCH.PDF

0 Wyatt Keller over 4 years ago in reply to Robert Ploeg

TI__Guru** 105590 points

Hello Rob,

Can you send a screenshot of the bits on the dashboard when the gauge wakes up? Do you have any bits set that would keep the FETs off? Some protections may be triggered to prevent charging. Were any other parameters changed on the gauge?

Sincerely,

Wyatt Keller

0 Robert Ploeg over 4 years ago in reply to Wyatt Keller

Prodigy 240 points

Hi Wyatt,

I have placed the battery at the engineers to check and passed onyour questions. No answer yet but I will get back at you asap.

Best regards,

Rob

Power management

Power management forum

BQ40Z60: Pre-charging after powerdown