When you talk about operating an electrical device over time, that is "work". Work requires "energy", for all intents and purposes work equals energy. In the case of your hundred-watt light bulb, over one hour it will take 400 watt-hours of energy to operate. You'll note that you're charged for your power in units of kilowatt-hours. A kilowatt-hour is a unit of energy and it will do a certain amount of work.
Now a watt is a unit of "power". Power is the RATE at which you do work. (Specifically a watt is one joule of work per second, but we seldom use the unit of joules because a joule is very small.) So to use an analogy, power is to work as speed (miles per hour) is to distance (miles). If you take the product of power over time, you get energy. 100 watts times 4 hours equals 400 watt-hours. In theory, your 400 watt inverter should be able to operate four 100 watt light bulb forever as long as it is supplied with a source of energy. So how long you can maintain your light doesn't depend on the inverter, but rather the inverter's source of power. So you have to know how much energy is stored in the battery to determine how long you can operate the light. Battery energy ratings are given not in watts, but rather amp-hours. You have to know the voltage rating and the amp-hour rating to figure out how much energy is in the battery. Energy happens to be equal to voltage times current, so if we multiply the voltages time the battery's amp-hour rating, we get the battery's energy in watts. So if I have a 12 volt, 50 ampere-hour battery, it should hold 600 watt-hours of energy. IN THEORY, those 600 watt-hours will operate a 100 watt light bulb for six hours.
Now when you start operating a load from a battery through an inverter, you get all sorts of things that mess up your calculations. First, the amp-hour rating of a battery is always very optimistic and assumes a very light load that will maximize the rating. Also, the battery's voltage drops as it is discharged and will eventually fall below what the inverter requires to operate long before the battery is fully discharged. The last thing is the efficiency of the inverter, which is probably not very good.
We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today. [ About Us ]
Today's Featured Article - Farmall 460: That's My Girl - by LeAnn R. Ralph. How many sounds can you think of that are as familiar to you as your own breathing? What about the hum of your refrigerator? Or the thump of your clothes dryer? Maybe the engine of your car? You hear those sounds every day, and you don't think much about them, do you. I can think of a few common, ordinary sounds in my daily life, too.
... [Read Article]
Latest Ad:
1964 I-H 140 tractor with cultivators and sidedresser. Starts and runs good. Asking 2650. CALL RON AT 502-319-1952
[More Ads]
All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy
TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.
