Iceman

My laptop AC Adapter is 16V -- 4.5A

If I buy a cigaret lighter type plugin that is:
15/16/18/19/20Volt, 3,5A (max.)

Does that mean that the battery will not charge (but the laptop will run fine)?

Will my car battery drain if the laptop is turned off, but plugged in to the power source (power source is always on, even if the car is not running)?

Thanks,
IceMan

Enforcer

Although the laptop AC adapter will give upto 4.5A, it does necessarily mean the laptop needs that much (although it may well do). The chances are that the laptop will charge but may not run properly, charging does not need that much current, it make just take longer to charge fully. The main issue will be with the LCD screen and back-lite, floppy running, CD running hard-drive running, the processor running there will be enough current for all that.

there will be battery drain, but it should be negligible

__________________

DodgeCummins

I have tried this...and probably you will not have enough juice...especially if your car voltage drops a tiny bit. Get something that has the correct volts...and at least that many amps. You will be happier in the long run.

__________________
current projects