I don't think the wiring is correct. I am not familiar with that modification of the original done by user download @ CPF. I did the same mod here following the original wiring scheme below and have had no issues. If the drivers are getting fried, then V is too high. I would suggest to redo the wiring.
If I recall there was some difficulty using that mod with XML’s. Originally, CPFuser download did it with P7’s that have a higher Vf. I used a slightly different method Here see Post 100 for a picture and description of the mod. For 3 cells it used an L78L05 voltage regulator in place of one of the 7135 chips. Another less complicated method uses a Zener diode and resistor. Both methods fix the input voltage of the mcu and disable voltage monitoring.
A diode by itself in series should soak voltage by 0.6V so in theory it should work. But with low pushing 6.5V, after diode the driver will still get 5.9V, too close to the 6V limit for comfort. The voltage peaks will probably kill off the driver slowly.
Maybe a diode and a small resistor will work. I’ll leave the value calculation to the experts.
i added the resistor but the driver still getting about 6.2 volts at low i think i should try Zener mod , but do i have to add the resistor in the driver