Tuesday, Mar 02, 2004 at 20:57
OK, here goes; Just did some checks on my old HP Inspiron 2100 (Pentium 233MMx). This computer uses a 19v 3.1A mains power pack.
In the vehicle, I run it off a DC-DC converter putting out about 19.5v, capable of delivering 3.5A.
With no load, the converter draws 45mA from the 12.7v vehicle supply. Charging the computer battery, computer running, the draw from the 12.7v supply is 4A. Once charged, the results are:
- Hibernate mode: 0.2A
- Running, screen shut down: 0.7A
- Running, screen active: 1.2A
- Running, accessing hard drive: 2.0A
These are all current draw at 12.7v. Different laptops will give different current draw, but this should give you an idea. A modern Pentium-M/Centrino laptop will give much better results.
You'll note that the converter draws bugger-all with no load. Running a combined 12/240v inverter and a power pack will not come within cooee of this efficiency. (I could run some tests, but I don't see the point)
Hope this info is of use to you.
Gerry
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