12 volt cig plugs & inverters

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Forum Name: General Discussion
Forum Discription: General Mobile Electronics Questions and Answers
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=28509
Printed Date: May 28, 2024 at 3:35 PM

Topic: 12 volt cig plugs & inverters

Posted By: SVrider
Subject: 12 volt cig plugs & inverters
Date Posted: March 16, 2004 at 7:14 PM

I have a few questions about cigarette lighter plugs and inverters.

How many watts of 110 can you draw from an inverter plugged into a cigarette lighter? I think its 150 watts, but I need to know for sure.

How clean is the power coming out of an inverter going to be? It needs to run a laptop, so I would imagine it has to be good, but I don't know. Is a surge protector enough? Can you recommend some decent inverters?

Is 150 watt going to be plenty for a laptop and a small sub/sat speaker system?

I appreciate responses posted_image

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-Chris
2001 Suzuki SV650

Replies:

Posted By: Mad Scientists
Date Posted: March 17, 2004 at 8:04 PM

To figure output, multiply 12 * size of the fuse for the lighter. Watts = volts * amps, so 12v * 10 amp (fuse) equals 120 watts.

Even the cheap inverters from places like Sams Club and BJ's will work ok with a laptop power supply..

The only way to know how much these items consume is to measure them.. use a DMM and measure AC amps.

The inverters I use are from BJs.. Sam's Club has similar ones also.. Last time I checked at BJ's, the 700 watt unit was $40.. the 350 watt unit was $24.

Hope this helps,

Jim

Posted By: SVrider
Date Posted: March 18, 2004 at 4:00 AM

Yeah, thanks.
I might find out by looking at the specs for the laptop too... duh posted_image

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-Chris
2001 Suzuki SV650

Posted By: markcars
Date Posted: March 18, 2004 at 4:27 AM

Jim,

I have purchased several inverters over the years, but I remember purchasing my first two, I cannnot remember the wattage on them (I willhave to check them and let you know when I find them) but sadly, they used to die out when powered to my laptop. Every few minutes, the overload protection would trip. The laptop I had at that time was a very "low-power" consumptio one too. It had almost everything external, such as external floppy drive, external cd-rom drive. A Toshiba Prestige model 7000 if I remember correctly.

At that time I figured that my inverter was too weak and purchased a 600 watt one with three sockets. Never used it yet. However I only could turn the laptop off and just use the inverter for charging. However I later purchased a DC to DC auto converter with some voltage regulator inside of it I assume. That worked like a champ even with my laptop on! (I used to use my laptop as a GPS unit before)

Also can you measure amps with a meter on AC? I thought you could only measure amps for a DC current. I am sure you can clarify my doubts. Thanks,
Mark

Posted By: Mad Scientists
Date Posted: March 20, 2004 at 9:36 PM

Be careful when using the dataplate to determine if an inverter can power a specific device.. AC power has a component known as Power Factor. I have a coffee grinder that's rated at 60 watts, but because of a truly horrid power factor the grinder draws in the neighborhood of 5 amps.. which can't be supplied by my 350 watt inverter. Do a google search on 'power factor'.. interesting stuff.

I imagine that any meter that can measure DC amps should be able to measure AC amps.. just be careful. You can buy inductive meters that don't require you to break the circuit.

You can buy inverters now at places like BJ's and Sams Club for something along the lines of a 350 watt unit for $24, a 700 watt unit for $40, and a 1000 watt unit for $80.

Hope this helps..

Jim