To get an average output power like mine (400W) you could set the max value to 212 (400/480*255). I have it set to 136 for a 750W heater (400/750*255).
Your bed has a larger mass as it is 6mm thick where mine is 3mm. This means that it will react slower. Do a PID for the max temperature you are aiming at and let it cycle 10 times. Just give that a try.
My parameters are :
#define MAX_BED_POWER 136 // limits duty cycle to bed; 255=full current
//#define PID_BED_DEBUG // Sends debug data to the serial port.
// Keenovo 750W
#define DEFAULT_bedKp 75.81
#define DEFAULT_bedKi 14.83
#define DEFAULT_bedKd 96.87
// FIND YOUR OWN: "M303 E-1 C8 S90" to run autotune on the bed at 90 degreesC for 8 cycles.
#endif // PIDTEMPBED
@csorrows But I should stop posting comments in threads... The system tells me that I should give others also a chance to post something...