Problems charging laptop from 12V DC battery

Please can somebody tell me why my 12V ship's battery is powerful enough to start my boat's inboard diesel engine, but not powerful enough to charge my Dell Vostro 1510 laptop either with a 12V DC adapter, or via an inverter to mains 240V and then the normal mains charger? Thanks.

 

I can't explain without using a voltmeter. How are you connecting the adapter and inverter to the battery? Are you sure that there is power at that point?

John

 

It probably has to do with the amount of power or current that 12V can provide.

Engine starter batteries typically are designed to create the spark needed to get a gas reaction going, short quick and dirty. Laptop's require constant power for minutes and hours at a time.