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Original question:

BQ24295: BQ24295 question

BQ24295: BQ24295 charger disabled

Vitor Miranda
Prodigy 30 points
Part Number: BQ24295
Other Parts Discussed in Thread: BQ27510-G3

I´m facing the same problem. I have an overdepleted battery (around 1V) and the charger does not seam to be working, even if i leave it charging for around 4hrs. It only works when i manually charge the battery for a few seconds (using a multimeter probe connected to a power supply) to raise its voltage above 2V (VSHORT). The problem with this aproach is that, first of all, its a workaround and second, i have to keep oppening the product case (thats sealed with glue).

Q1: Is there a way to change the 4hr safety timer off for batteries under VSHORT voltage?

Q2: Is there a way to change the VSHORT voltage value to a lower value?

  • 0
    TI__Mastermind 25800 points
    Hey Vitor,

    Unfortunately not. These are fixed thresholds within the device.

    To understand your comment however, you mention that when you use a power supply versus the charger, you can get it to charge up to 2V.

    What is the current your power supply is providing in the moment it is connected? Our charger is providing ~100mA in this VSHORT state, which should be enough to raise the voltage. I suspect something else may be happening or you have an extremely large battery.



    Regards,
    Joel H
  • 0 in reply to Joel Hernandez II
    Prodigy 30 points

    When i plug the power supply dirctly to the battery tuned to a voltage around 3.5V the current splikes to around 1A and falls fast. It takes only a few seconds for the voltage to go above 2V. When i plug the product to the USB and measure de voltage on the battery terminals i see no increase overtime, instead i notice the battery voltage decreasing. That does not happen when the voltage is above I too suspect there might be some other issue. I have attached a print of my design. I´m also using the bq27510-G3 to monitor the battery. The battery is a standard 2250mAh 3.7V cell

  • 0 in reply to Vitor Miranda
    TI__Mastermind 25800 points

    Hey Vitor,

    A few more questions:

    If you current limit your power supply to 100mA, does it still charge to 2V (external power supply)?

    When you connect a USB to the charger, is the gauge seeing any current flowing into the battery from the charger?

    Is there anything else connected to VBAT? some device or load?

    How are you controlling the charger via I2C? Is anything getting set on the charger? Do you have a register dump of the charger while its charging this over-depleted battery?

    Regards,

    Joel H

  • 0 in reply to Joel Hernandez II
    Prodigy 30 points

    Indeed, i have reviwed the entire schematics and there seams to be some other components linked to the BAT terminal wich might be drawing the 100mA curent. Also changing the code to output those reristers so we can take a look into what the charger is doing. As soon as i have that information i will post it here... 

  • 0 in reply to Vitor Miranda
    TI__Mastermind 25800 points

    Okay Vitor.

    Let us know. If you're drawing 100mA else from the BAT pin, it is likely that the current is not being supplied to the battery to close protectors/raise battery voltage.

    Regards,

    Joel H

  • 0
    TI__Genius 10240 points
    Victor,

    We did not hear back from you. Is the issue solved?