Area Representative Nick Bassett Posted October 7, 2020 Area Representative Share Posted October 7, 2020 Hi all,Had a problem starting my K series this afternoon when hot - it's had the K click mod done recently which seems to be working well for hot starts. Cut a long story short, the RAC man found that the in-line fuse from the relay to starter had blown - it was only a 15A fuse fitted. When he measured what was being drawn when the car was cranked, it was nearer 24A, so a 30A fuse has now been fitted!My question is... is 24A about right, or should it be much less?Thanks! Link to comment Share on other sites More sharing options...
Member Jonathan Kay Posted October 7, 2020 Member Share Posted October 7, 2020 Private Message sent. Link to comment Share on other sites More sharing options...
revilla Posted October 7, 2020 Share Posted October 7, 2020 About right. That's why the "ECU Fuse" in the K Series loom (which normally supplies the whole engine loom including the starter solenoid current) was uprated from 20A to 30A. I measured around the 20A mark on mine too. Link to comment Share on other sites More sharing options...
revilla Posted October 7, 2020 Share Posted October 7, 2020 PS: There are actually two windings in the solenoid, a "pull in" coil and a "hold in" coil. The pull in coil draws a much higher current than the hold in coil; once the solenoid core is pulled into the coil it takes a lot less current to hold it in. The starter is cunningly wired so that when the solenoid is fully pulled it closes the power contacts to the motor, which effectively removes the earth route for the pull in coil, turning it off (it earth's through the motor windings, so powering the motor takes its earth to battery voltage and shuts it off). From memory I think 20A+ is about right for the pull in coil rather than the hold in coil, but I may be wrong on that. Link to comment Share on other sites More sharing options...
Area Representative Nick Bassett Posted October 7, 2020 Author Area Representative Share Posted October 7, 2020 Thanks both - sounds like I was worrying about nothing then! Link to comment Share on other sites More sharing options...
revilla Posted October 7, 2020 Share Posted October 7, 2020 To add a bit more confidence...1mm2 thin wall cable is rated at 16.5A.2mm2 thin wall cable is rated at 25A.For the starter solenoid cable, Rover used 3mm2 cable rated at 33A. The cable may be a bit over specified to minimise resistive losses but they certainly expected it it carry a fair current. Link to comment Share on other sites More sharing options...
Area Representative Nick Bassett Posted October 8, 2020 Author Area Representative Share Posted October 8, 2020 Very interesting Andrew Link to comment Share on other sites More sharing options...
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