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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The surface charge is long gone. The glow plugs are pulling 100A for about 5 sec before the starter is engaged. As seen from this plot, battery voltage starts below 12V and drops below 10V from the 700A spike.
This is a plot of the current in the starter cable and chassis battery voltage. The data rate is limited due to the speed of the A/D multiplexer (switching between voltage and current measurements).
Data is taken on a Sprinter (Mercedes 5-cylinder) diesel with 80k miles.
This is a plot of the current in the starter cable and chassis battery voltage. The data rate is limited due to the speed of the A/D multiplexer (switching between voltage and current measurements).
Data is taken on a Sprinter (Mercedes 5-cylinder) diesel with 80k miles.
tatest wrote:
That 700 is a spike fed by surface charge on the battery plates. Internal resistance in most lead-acid starting batteries limits deliverable current to 400 amps or less. NiMH could deliver more.
