RE: [A/S] 12-volt outlet in truck

["Perry Joe Scudder" <perryjoe@xxxxxxxxxxxxx>]

> We like to travel with our laptop in operation.  I use a 
> 12-volt inverter and 
> am now on my 4th one.  The laptop is rated at 90 watts output and the 
> inverter is rated at 200.  However, when plugged in it either 
> overloads or blows a 
> fuse in the truck.  (I'm sure there are more technical terms 
> for what I am 
> trying to say).
>

Hi Verna,
I had the same problem after switching from a Gateway laptop to a new
Toshiba laptop. The Gateway had worked perfectly for 5 years with the
supplied DC adapter that plugged into the Cig Lighter socket. I got the
Toshiba with the supplied 90 Watt adapter for the car, and it would not work
at all. I thought it was just a bad adapter, so I took it back to Best Buy.
They checked it on their bench tester, and it was working fine, but they
could not get it to work on the computer on their bench. They ordered a 120
watt adapter for the computer, which turned out to work like you say yours
does - part time. I then switched to a 450 Watt Inverter that was designed
to be plugged into the car's lighter socket. It kept putting out a high
pitched alarm that meant it was working in overload according to the book
that came with the inverter. I then switched to a 750 Watt Inverter, and ran
8 GA (about the size of a wooden pencil) wire direct from the battery to the
inverter. All was well, and worked perfectly. I still had the 450 Watt
Inverter, so tried it with the 8 GA wire setup, and all worked well also. My
learning from all this - and about $200 - were two. One was the amount of
power required by the two computers were vastly different - the Toshiba took
enough to run a small village. The second one was the fact that the "wire
loss" by using the small 14 or 16 GA wire in the truck harness was causing
the problem at full current draw, and the voltage regulator and charging
system in the truck were causing the voltage to drop below the "loaded"
requirements of the inverter when the truck battery was fully charged.
 
> I am assuming that the outlet in the truck is faulty.  When 
> checking the 
> power options on the computer while plugged in, it keeps 
> flipping back and forth 
> between AC power and battery power.  When plugged into a 
> 12-volt outlet inside 
> the trailer it shows constant AC power.

I think this means your computer is running off the power inputted from out
side the computer when it says "AC", and not from the on board batter when
it is getting power from outside. Usually the adapter from house AC changes
the voltage to some level of DC at around 12 to 18 volts, but your computer
says it is getting AC.  
> 
> How do you check these cigarette lighter thingies (to use one 
> of Hunter's 
> terms) to see if they're OK?

What does the computer do if you plug it into the other socket in the car? I
would be willing to bet it will still not work even though the SmarTire
system works fine in either socket. 

You can test the socket by using a volt meter or simply plugging in some
small DC requiring device to see if it works - try plugging the SmarTire
unit into the one you normally use for the computer as a check.

I hope some of this helps get you up and working - it can get very
frustrating at times.


Joe Scudder
WBCCI 8624 - and a top of the line Toshiba Lap Top that is now on its 3rd
hard drive in less than a year.