Salvo
Feb 25, 2016Explorer
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 100A.
After 12 sec the engine is cranked. Current spikes to over 700A. It takes about 1 sec to start. After ignition, glow plug current settles to about 90A.
At 16.5 sec the alternator kicks in. Battery current ramps (negative) to about 20A. The battery is now charging. Negative current is charging current.

Just before the 8 sec mark the ignition is turned on. The glow plugs pull over 100A.
After 12 sec the engine is cranked. Current spikes to over 700A. It takes about 1 sec to start. After ignition, glow plug current settles to about 90A.
At 16.5 sec the alternator kicks in. Battery current ramps (negative) to about 20A. The battery is now charging. Negative current is charging current.