Battery current during engine start
I was a bit curious how much current is pulled during my 5-cylinder diesel start. It's more than I thought. Just before the 8 sec mark the ignition is turned on. The glow plugs pull over 100...
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You guys got it right. The dynamic loading of the starter motor, created by piston compression is causing the current gyrations.
I think most if not all new cars have the ignition switch turn on a relay which in turn activates the starter solenoid. A lot less current goes through the ignition switch. On my new Miata, there's no key for ignition. Just a push button switch. The "key" is left in my pocket. The car doesn't use a key.
On a side note, automotive relays don't use a despiking diode any more. A resistor in parallel with the coil is now used. It allows the contacts to switch faster.
I think most if not all new cars have the ignition switch turn on a relay which in turn activates the starter solenoid. A lot less current goes through the ignition switch. On my new Miata, there's no key for ignition. Just a push button switch. The "key" is left in my pocket. The car doesn't use a key.
On a side note, automotive relays don't use a despiking diode any more. A resistor in parallel with the coil is now used. It allows the contacts to switch faster.
