INR18650-25RM Battery Protection Circuit (High Discharge)

[Leo86]

Hi,

I am doing a project that uses the INR18650-25RM high discharge battery and the circuit I used in my prototype didn't work because I extracted a 9A (continuous) current from the battery.
The circuit I was using to protect the battery was this:
https://www.eevblog.com/forum/projects/pain-and-suffering-getting-the-dw01-and-8205a-protection-circuit-work-right/
But as I said, this circuit can not stand when it pulls too much current from the battery.
To solve this problem I am considering replacing the circuit with the MOSFET FS8205 with two DMT2004UFV-7 which has a higher current.

Does anyone have any suggestions?

[jbb]

The standard protector chips protect on voltage and current.  Voltage is sensed directly, and current is sensed by the voltage drop across the protection MOSFETs.  So you don't actually care about the MOSFET 'current' rating (which is generally not very useful anyway), but instead the MOSFET on resistance at the available gate drive voltage (i.e. cell voltage).  This could be as low as 2.5V, so check your MOSFETs carefully, and be prepared for quite big tolerances when the temperature changes.

Paralleling MOSFETs will reduce the on resistance and thus get a higher trip current.

The protector chips come in a variety of configurations, with different voltage and 'current' (i.e. voltage drop across the MOSFETs) settings.

One interesting wrinkle: the discharge current is passing through 2 MOSFETs in series, which doubles the resistance.  You might be able to find (and source, don't forget sorting) a protector chip which lets you have separate discharge and charge connections, with the discharge current only passing through a single MOSFET.  This instantly halves the resistance.   The charge input might only need a 3A rating, which makes MOSFET selection much easier.