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# Physics/Watts

Question
QUESTION: I purchased an electric kettle for heating water on the road and a 800 Watts inverter so I can power it through the cig lighter. What are Watts exactly and can I get too powerful  a Watt converter for my purposes? I don't want to destroy the inverter or the kettle.

ANSWER: When we go use equipment in the field, we run across this all the time.  Inverters have fuses.  You're far more likely to blow that than anything that draws the power or the inverter itself.  And by far, I mean that they're designed that way.  800 Watts is a really big honkin' inverter, but water heater devices do draw a mean amount of power.  I'd go find the fuse and stop (most likely at a truck stop or well-equipped gas station, perhaps auto parts store) and make sure I had extra fuses...just in case.  You'd be really surprised what running fancy laptops draws when you're just trying to get basic equipment to work in a vehicle on top of it.

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QUESTION: It may have been 400 Watt. The unit cost roughly \$50. Is there such thing as too much Wattage? The thing plugged it will only take what it needs? What exactly is a Watt versus volts, amps, etc?

ANSWER: Watts is a unit of power (energy per unit time).  Watts = Volts*Amps.  The thing plugged in will demand a number of amps (amount of electrical current) at the set voltage (driving potential energy that causes electrical current to flow) that your inverter attempts to supply.  If that current is too high, it will blow a fuse.  The inverter has a fuse in it for this purpose, to protect it from burning out.  Do you know the wattage of the water heater?  They generally draw more current right at startup, just like a light bulb, since the heating coils gain extra resistance as they get hotter (lowering the current).  So it is right at startup that you are most likely to blow a fuse, much like the reason that light bulbs burn out when you turn them on.

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QUESTION: I couldn't find any technical info on it. It is a T-Fal electric kettle. I emailed their website. Not sure when or if they'll get back to me.

We're getting outside of my wheelhouse, I'm not in appliance repair, but a quick google search seems to indicate that these are in the 1450-1750 Watt range.   You'll blow a fuse for sure.  It's a pretty typical range for small water heating devices, actually.

Physics

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#### Dr. Stephen O. Nelson

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