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Old 02-21-2009   #4 (permalink)
S_Egbert
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Default Re: Laptop power in the car

Quote:
Originally Posted by brian.austin View Post
A DC to DC supply would probably still require a voltage change....
Personally, I'd just go for the inverter.
Thanks Brian.
Yes, a DC to DC unit has to do a bump up in voltage as well as regulate it since laptops are in the 16 to 18 volt range.
I probably will go for the inverter. Most of the better ones have a self shutoff if the vehicle voltage drops below a certain point so even using it with the engine off won't leave you with a dead battery.

Quote:
Originally Posted by JackAZ View Post
Be cautious of using an inverter to charge Li-ion batteries. An inverter doesn't generate a true sine wave like an AC power source. Because the inverter is taking a DC input and simply multiplying it several times to generate the specified AC voltage it clips both the high and low ends of the AC sine wave. Li-ion batteries are sensitive to this and charging them from an inverter can shorten their life.
Thank you Jack,
I would think that once the square wave AC goes through the laptop's power brick and is converted back to DC that this would be a non issue.
No matter, since li-ion batteries have a finite lifespan not much longer than two years anyway I won't worry about that too much. Like you, my time spent on battery power is very small.
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