Hi,
Currently we have a radiator fan powered from one 20A output of PDM15 but switched low by M400 (Figure 1). Our previous electrical staff did the wiring and personally, I do not feel comfortable feeding high current (~7A) to M400 -- we suspect this setup caused the PDM to reset while the car was running at high revs.
So we are looking at developing a solution similar to Motec DHB, but made in-house due to budget limit. The idea (shown in Figure 2) is to have a microcontroller continuously polling the CAN bus for specific messages, ET for instance, and output 5kHz (or 10kHz) PWM with varying duty cycle depending on the parameters (ET, WT, OP, RPM etc). As I understand it the output of PDM is limited to 10Hz, and seeing it'll be switching at high frequency, I was wondering whether PDM will get damaged from providing power to mosfet which will be driving the radiator fan?
Cheers.
Eric S.