watts requirement for lap top? HELP!

[bill mudd]

just purchased a 140 watt cigarette lighter adapter (by cyber power) that they said would power a notebook - but it wont power my lap top - Does anyone know ABOUT how many watts an average laptop requires while running a delorme map series?

 

[Bill Hamilton]

I use a Targus 70 watt on mine. The 140 should be more than enough to run yours. Maybe it isn't working correctly.

 

[PaulChambers]

I have a 100 watt inverter that runs my laptop with DeLorme GPS, Wi-Fi card. It does just fine for me. Check with your laptop power supply and see what its ratings are.

 

[cedwards]

Check and see that you are cetting enough wattage to the cigarette lighter. You may not be getting enough voltage to the inverter.

 

[Tim Johnson]

Originally posted by bill mudd
just purchased a 140 watt cigarette lighter adapter (by cyber power) that they said would power a notebook - but it wont power my lap top - Does anyone know ABOUT how many watts an average laptop requires while running a delorme map series?

This info should be useful.


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Helpful formulas:

To Convert AMPS to WATTS:


Multiply: AMPS X 120 (AC voltage) = WATTS
This formula yields a close approximation of the continuous load of the appliance
To Calculate approximate Startup Load:


Multiply: WATTS X 2 = Starting Load
This formula yields a close approximation of the starting load of the appliance, though some may require an even greater starting load. NOTE: Induction motors such as air conditioners, refrigerators, freezers and pumps may have a start up surge of 3 to 7 times the continuous rating.
Most often the start up load of the appliance or power tool determines whether an inverter has the capability to power it.

For example, you have a freezer with a continuous load of 4 amps, and a start up load of 12 amps:

4 amps x 120 volts = 480 watts continuous
12 amps x 120 volts = 1440 watts starting load

You would need an inverter with peak-surge rating greater than 1440 watts.

FORMULA to convert AC Watts to DC Amps:

AC Watts divided by 12 x 1.1 = DC Amps
(this is the size vehicle alternator you would need to keep up with a specific load; for example, to keep up with a continuous draw of 1000 watts, you would need a 91 amp alternator)
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The above info found at http://www.donrowe.com/inverters/inverter_faq.html
There are other noteable questions and answers on the site.


As for where to buy inverters....I bought mine at http://www.techbuys.net/techbuys2003/power...-inverters.html for an extremely affordable price.

Hope that helps some.

 

[bill mudd]

Thanks all - I really thought that this 140 would do it (sounds like you guys feel it should too) - Ill have to check out my requirements on my laptop (BUT DOESNT IT SEEM LIKE IT SHOULD BE MORE THAN ENOUGH - generally speaking?)
If my lap top requires this much, it will kill whatever batteries supply it, right?
I simply cant chase with something so hungry - uggg and its NEW!
am I the only one with this issue? has anyone run their converter direct to the battery and bypassed the cigarette lighter because of this problem?
THANKS ALL

 

[Bill Hamilton]

I have my inverter direct wired to the battery through an added fuse block and accessory outlet gang box I made. This limits the fluctuation caused by electrical draw on you vehicles stock wiring. I have not had a problem with it at all.

 

[Robert Dewey]

Hmm... The AC adapter that came with my laptop says it uses 2Amps, so that would be 240Watts. I am assuming the AC adapter uses more electricity than just the battery would, as the AC adapter both powers and charges the laptop at the same time.

 

[Bill Hamilton]

Originally posted by bill mudd
just purchased a 140 watt cigarette lighter adapter (by cyber power) that they said would power a notebook - but it wont power my lap top - Does anyone know ABOUT how many watts an average laptop requires while running a delorme map series?

B.T.W. What brand of laptop and processor are you using? The 'true" Pentium 4 processors without speedstep technology eat up power in a hurry where the new Centrino uses much less. Is the adapter you bought a DC to DC converter or DC to AC inverter?
The one I have is a Targus DC to DC converter but I also use a DC to AC inverter when needed.

 

[Tim Johnson]

Originally posted by rdewey
Hmm... The AC adapter that came with my laptop says it uses 2Amps, so that would be 240Watts. I am assuming the AC adapter uses more electricity than just the battery would, as the AC adapter both powers and charges the laptop at the same time.

If your adapter draws 2 Amps you would need 240 watts minimum inverter (probably not advisable). 300 watts would be ideal if the laptop is all you use with the inverter. With inverters its always better to have too much than not enough. Most equipment used for storm chasing usually would not require high start up watts. Things like a small fridge, or power tools would demand more.

Mine is an 800 watt inverter (and at 50-60 bucks theres really no reason not to have this much), and can get away with running the laptop, cell phone charger, camcorder charger at the same time if needed. Be careful.....just because you havent seen any trouble thus far. Do the math and make sure you have enough for the equipment you run.

AMPS (of each piece of quipment you plan to run simultaniously) X 120 V = the inverter watts needed for safe and reliable operation. If the numbers are tight, get a higher wattage inverter, or run less equipment at the same time.

 

[cedwards]

One note. If you do go with a higher power inverter, you will not be able to run it off your cigarette lighter. You will need to run a heavy duty cable to your battery. I use 5 guage wire with a 100 amp fuse from the battery to a terminal strip inside the car that runs all my equipment.

 

[Tim Johnson]

Good point Charles.

The irony of inverters :? Take DC from your car battery, convert it to AC, so you can plug all your adapters into it and convert it back to DC :roll: Things to make you go hmmm!

 

[Rockwell Schrock]

Two words: iGo Juice

 

[bill mudd]

I've got the WINBOOK 2004 pent 4 (power guzzler)
and the factory wont tell me what it will take - only that they have a cure for $130!!!
sounds like I need at least 300 amps hard wired to the battery, which is what Im suspecting now
besides how could that small gauge cigarette wire be enough for 300 amps (it couldnt be) duuh guess I was looking for the easy way out
thanks all for your input - problem solved (for now)

 

[cedwards]

You are getting amps and watts backwards. If you need 300 amps at 12 volts, that is 3600 Watts.
If you go with a 300 watt inverter, you wil use about 25 amps at 12 volts. Most cigarette lighter plugs are fused at 30 amps, but that is cutting it a bit close. You should still wire it to the battery. Don't forget to put a fuse inline.

You should be able to find an inverter for under $50