12V to 19V converters?

kaspaas said:
Hi,

Laptops usually have 19V DC power supplies.

Why convert 12V DC to 220V AC and back again to 19V DC?

Can't one get a 12V DC to 19 V DC converter?
Click to expand...

I bought a DC->DC 150W switchmode power supply from Electronics 123 (input voltage: 11 - 16Vdc) about a week ago for my laptop, it's got a car lighter plug and voltage selector (selectable voltages: 15, 16, 18, 19, 20, 22 or 24Vdc), also includes many plugs (the type that plug into the laptops,etc) it works very well only problem is it costs R450 :(

Might be possible to get one from communica for cheaper, if you're not in Pretoria then I'm not sure where you can get one tho, Electronics 123 does ship, I think...

http://www.electronics123.co.za/Mai...oductList&DisplayMode=Category&CategoryID=874
 
Last edited:
Gnome said:
I bought a DC->DC 150W switchmode power supply from Electronics 123 (input voltage: 11 - 16Vdc) about a week ago for my laptop, it's got a car lighter plug and voltage selector (selectable voltages: 15, 16, 18, 19, 20, 22 or 24Vdc), also includes many plugs (the type that plug into the laptops,etc) it works very well only problem is it costs R450 :(

Might be possible to get one from communica for cheaper, if you're not in Pretoria then I'm not sure where you can get one tho, Electronics 123 does ship, I think...

http://www.electronics123.co.za/Mai...oductList&DisplayMode=Category&CategoryID=874
Click to expand...

Thanks.

I'm thinking of rigging a deep cycle 12V battery with a suitably sized charger in my office and running my laptop from there when then power fails.

Obviously it is a question of effeciency: Which is more efficient: 12V to 19V or 12V to 220V(Inverter) to 19V (normal latop charger)?
 
i Asked this question in another thread but the thread seems to be kind of dead now.

If you were to hook up a laptop to a car battery using the best method, how long roughly could the laptop run for.

Any Ideas.

The car battery could obviously be replaced with a quality deep cycle battery.
 
buy this
http://www.carnetix.com/CNXP1900.htm
12dc/dc regulator, used to run laptops as carpcs, i.e. from a 12v source giving a 19v output.
this avoids the messy dc-->ac--->dc conversion you will get when using an invertor, as well as the power losses involved.

from a good car battery, you should get about 15 hours of runtime

240v invertors are about 60% efficient, so the time will drop to about 9 hours
 
BiteMe said:
buy this
http://www.carnetix.com/CNXP1900.htm
12dc/dc regulator, used to run laptops as carpcs, i.e. from a 12v source giving a 19v output.
this avoids the messy dc-->ac--->dc conversion you will get when using an invertor, as well as the power losses involved.

from a good car battery, you should get about 15 hours of runtime

240v invertors are about 60% efficient, so the time will drop to about 9 hours
Click to expand...

Thanks
 
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