Where can I get more DC Power

[acroporas]

I have an 05 Prius. I want to be able to power my Laptop by the car. But the cigarette lighter will not give me enough power. So I want to add a higher capacity power outlet.

Does anyone have any suggestions as to where to draw the power from. The battery in the right rear corner is the obvious choice but if there was a good spot in the front half of the car it would save a lot of work.

Since I know someone will ask, the computer is a Dell E1705. The power supply is rated at 90 Watts. I am using a DC -> AC converter rated at 200W. This works fine in the cigarette lighters in my other 4 cars but not the prius. The cigarette lighter outlet on the Prius is labeled as capable of 100W(or was it 120) so it should be fine as it is. But it doesn't. When I plug the computer in, it gets pulses of power lasting about 3 seconds before cutting out.

[hobbit]

The Dell may be able to run straight off 12V. I had a dead battery
pack for mine, and after pulling the cells out of it simply wired
a 12V plug and a wire into the right contacts ... I clip that rig
in where the Li-ion pack ordinarily goes and the lappie runs fine
off 12V. The battery's nominal voltage is 11.1 or so, but the
power regulation inside the lap deals with 14V fine and in fact
winds up drawing *less* current as a result.
.
If you need a beefier connection for your inverter, though,
http://techno-fandom.org/~hobbit/pix/prius-ferrups.jpg
http://www.priups.com/misc/intro.html
http://hiwaay.net/~bzwilson/prius/priups.html
.
_H*

[auricchio]

Chances are there are heavy losses in all that power conversion, which causes higher than expected current draw. You're converting 12vdc to 120vac, then back to low-voltage dc (maybe even 12v!)

The 90w power supply is perhaps 75% efficient. Assuming 90w is the output spec for it, then it needs well over 150w of input to produce its rated 90w for the computer.

The inverter is probably 50-75% efficient, so to produce 150w it needs well over 300w.

The two conversions are costing big time. As hobbit suggested, it's far more efficient to get rid of all the conversions and feed 12v directly to the computer. (Assuming that's what the computer needs, of course.)

[acroporas]

Well, the computer needs 19.5 V DC. So the 12V strait in is not going to cut it.

I guess the battery in the back it is. Thanks for the links.

[auricchio]

Have you considered buying a cigarette-lighter adapter for the computer? These devices usually use DC-DC converters, which can be more efficient than what you're currently trying.

Sure, it'll cost some money, but it beats trying to run wires under carpets all through the car. If you do connect to the 12v battery, be sure to include a proper fuse.

[hdrygas]

<div class='quotetop'>QUOTE(hobbit @ May 24 2006, 07:10 PM) [snapback]260673[/snapback]</div>

The Dell may be able to run straight off 12V. I had a dead battery
pack for mine, and after pulling the cells out of it simply wired
a 12V plug and a wire into the right contacts ... I clip that rig
in where the Li-ion pack ordinarily goes and the lappie runs fine
off 12V. The battery's nominal voltage is 11.1 or so, but the
power regulation inside the lap deals with 14V fine and in fact
winds up drawing *less* current as a result.
.
If you need a beefier connection for your inverter, though,
http://techno-fandom.org/~hobbit/pix/prius-ferrups.jpg
http://www.priups.com/misc/intro.html
http://hiwaay.net/~bzwilson/prius/priups.html
.
_H*
[/b]

I run my duel core Intel Mac MacBook Pro off the DC jack in the dash just fine? I have a DC/AC converter that I plug in and then plug in the AC power supply with no problems.

[auricchio]

I'll just have to chalk that up to the efficiency of the Mac's design vs. the Dell. That oughta start a little skirmish...

[vlenac]

<div class='quotetop'>QUOTE(acroporas @ May 25 2006, 03:55 AM) [snapback]260668[/snapback]</div>

I have an 05 Prius. I want to be able to power my Laptop by the car. But the cigarette lighter will not give me enough power. So I want to add a higher capacity power outlet.

Does anyone have any suggestions as to where to draw the power from. The battery in the right rear corner is the obvious choice but if there was a good spot in the front half of the car it would save a lot of work.

Since I know someone will ask, the computer is a Dell E1705. The power supply is rated at 90 Watts. I am using a DC -> AC converter rated at 200W. This works fine in the cigarette lighters in my other 4 cars but not the prius. The cigarette lighter outlet on the Prius is labeled as capable of 100W(or was it 120) so it should be fine as it is. But it doesn't. When I plug the computer in, it gets pulses of power lasting about 3 seconds before cutting out.
[/b]

Have you tried with both power sockets:the center one, between front seats and the second in the dash panel? Because I had the same problem with the same system (Dell Inspiron 8200 with AC DC converter 150W) on the center socket(between seats) but with the power socket in the dash panel everything is working fine-no power downfall.

[hdrygas]

<div class='quotetop'>QUOTE(vlenac @ May 28 2006, 11:45 AM) [snapback]262076[/snapback]</div>

Have you tried with both power sockets:the center one, between front seats and the second in the dash panel? Because I had the same problem with the same system (Dell Inspiron 8200 with AC DC converter 150W) on the center socket(between seats) but with the power socket in the dash panel everything is working fine-no power downfall.
[/b]

I also use the dash power outlet FWIW.