It depends on the power supply.  We have a few computers which can be run off a lower-wattage power supply while running - it will not charge the battery at all.  If you attach a larger power supply, then it can charge and run.

Check with your laptop manufacturer.  It seems somewhat common to see power supplies with different wattage being offered.  The power supply with a higher wattage may be what you need to charge quickly and power the system while on.  Check to see if a larger power supply is available if you need to charge quickly while using the system.

Does a laptop computer charge faster when off?
I read Marc-André LaFortune's post about using the Presto multi cooker as a secondary sous vide machine.

I'm interested in doing this but it would appear to me that the machine is not accurate enough without modification to hold the pot to +/- .7 F.
Do you do this by monitoring temperature with a thermometer and switching it on and off, or with a PID controller like others have used?
