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Big Bear Hostel asked:

I have a Compaq Presario V5310us notebook. The AC power adapter says:

INPUT: WIDE RANGE INPUT (basically any AC in any country)
OUTPUT: 18.5V(18.5V) = 3.5a(3.5a) 65W

The generic car laptop power adapter I bought has the following voltage options:
AUTO DC POWER
REGULATED ADAPTER
INPUT: 11-14V DC 8AMP MAX
OUTPUT: (selectable) 15/16/18//20V DC 4A
22/24v dc 3.3a 80w max.

SP8II-80W

Which voltage should I select? and is there any risk?
I had been using a DC to AC inverter in the car with the AC power cable to the notebook, but this seems easier and like it might take less load on the battery?