Disconnecting the power source in the car (the battery) should be done negative first as the - is connected to the most available point of contact: the car body.
When the battery is fully charged, then you should unplug the adapter from the laptop. When disconnecting from the laptop, you ought to shutdown the computer first, switch off from the socket and then unplug the adapter.
Should I Disconnect my computer from power if the battery is full?
If you are asking if you should disconnect your computer from power once the battery if full, the answer is no. If you do so, your battery will keep discharging and charging. The number of times batteries can be charges is limited and if you unplug your computer every time it is full, it will quickly die.
Should I plug or unplug a lead into my laptop?
Years ago it would have been an issue, perhaps that is why people still think it's important. It must be safest to plug or unplug leads into the laptop when no power is present. This makes it potentially less harmful to the laptop if you somehow manage to misalign or short conductors when pushing the connector in.
Should you unplug a power supply when not in use?
The only reason to unplug it when you've turned it off is to help protect it from lighting strikes. And that's a very rare thing. Turning it off when not in use is probably a good idea in an area where power outages are common, though it's probably not really helping. It certainly won't hurt.
Can a laptop be disconnected from a power source?
Somewhere I read that connecting/disconnecting should be done using the laptop's adapter power plug and not the power connector. You can safely disconnect a laptop from the power source from either end.
Thank you a lot. Shut down then unplug. And yes if you live in a area where power goes iut at the utility this is a very good idea. I used to live in a rural area that had far more than its fair share of power outages and occasionally when the pwer came back on there were wicked sags and overvoltages.