BQ77915: BMS is turned off when the pack is charged or discharged

MounishPatel Seetha

Part Number: BQ77915

Hi,

I have designed 13s Bms using three bq791500 devices. Finally I tested the Mosfet gate voltages which around 9.5V but when the pack is loaded ( either connected to charger or discharged), Bms is turned off automatically.

》 I used 2.5milli ohm current sense resistor , all charging and discharging are under limits of 6 amps..I previously designed 10s BMS ( i used same 2.5 milli ohms without ant filters), which is working well. Could you please guide me what be the possible problem ,

》 I used 6 Mosfets ( 3 dsg mosfets 3 chg Mosfets ), Please attachment of picture

over 4 years ago

0 WM5295 over 4 years ago

TI__Guru 54715 points

Hi Mounish,

This looks like an almost duplicate to your other post https://e2e.ti.com/support/power-management/f/196/t/966057 Check for GND connection as suggested on the other post.

0 Xiaodong Cai over 4 years ago

TI__Prodigy 600 points

Hi,

For quick analysis of the fault, please take a look at the following:

1. Are the FETs turn off during discharging or charging?

2. If during charging, which FET is off or both? If during discharging, which FET is off or both?

After answering above two questions, you would know whether it is OV UV OC or OW because the corresponding FETs are only to be turn off in one condition. Then you may start looking into whether it is the Isense resistor, or wire connection or any other issue presented.

Best,

Xiaodong

Power management

Power management forum

BQ77915: BMS is turned off when the pack is charged or discharged