The Oil Drum

LCD's and wattage, HA, go check the wattage of PLASMA TV. You need an AC unit to keep the room cool from their heat ouput. Though Plasmas are not selling well now because LCD's are getting bigger.

Quid Clarius Astris
Ubi Bene ibi patria

Wow, I got quoted.

A watt-hour isn't very much. So it's not so surprising that a big TV uses a lot. By a strange circumstance, electric cars and video projectors are two of my biggest interests.

Most video projection technologies are "light valves". That means that a bulb provides a constant light source, and some arrays of shutters act to block part of that light to form an image. Even film projectors are light valves. So the standard output of the bulb is the baseline for the projector's power consumption.

Fortunately great strides have been made. My old JVC G10 front projector used a 400 watt xenon arc bulb for outstanding color accuracy, but it only lasts 1000 hours, and I simply couldn't afford to replace it. My new projector, an Optoma HD70 DLP, cost me $850, is brighter, has a much better contrast ratio, and uses a 200 watt bulb. Furthermore, I run it in the low output setting to increase bulb life to 3000 hours and reduce heat rejection.

The problem is, I keep forgetting that when I stop the player, the screen goes dark but the bulb is still cranking away in there. I try to limit use to 2 hours a night, but I keep pausing the movie for things.

The next goals for power reduction are the use of LEDs as bulbs, and the replacement of plasmas and flat LCD panels with OLED panels. So far, the former are limited to conference-table screens.

As for cars, I know of some watt-hour figures for some other vehicles. The Prius is commonly said to consume 250 watt-hours/mile. However, a dozen years ago AC Propulsion converted a Civic to run on lead-acid batteries:

"In June of 1996, at 77,000 km, the AC Propulsion electric vehicle traveled 233 km (145 mi) on one charge over Southern California Edison’s Pomona Loop, a 31.2 km (19.4 mi) circuit of city streets in and around Pomona, California. The Optima spiral-wound lead-acid EV batteries had been installed at 65,000 km, and the new range mark represents a 23% improvement over the best range achieved with the previous generation Optimas. The AC Propulsion EV completed the range test with an average energy consumption of 78 Wh/km (126 Wh/mi)."

I have to wonder what they knew that GM did not. Top speed was about 80 mph, 0-60 in 6.2 seconds, and a weight of about 3500 lbs.

Solectria also did some great work in those days, building a handful of Sunrise composite sedans in lead-acid, NiMH and lithium ion versions:

"Solectria Corporation announced today that unofficial
results indicate the Solectria Sunrise electric sedan powered by Ovonic
Nickel-Metal Hydride batteries set a new electric vehicle range record by
completing 375 miles on a single charge in the third day of racing in the
1996 NESEA American Tour de Sol, the national solar and electric vehicle (EV)
championship."

Here's pictures:

www.austinev.org/evalbum/655

The secret is the weight.

You have to be careful about comparing the same quantities. In an electrical appliance we generally compare the power delivered to the device by the electrical service.

In an automobile we measure the fuel consumed, not the power generated by the engine. A gallon of gas does have roughly 36 kWH of energy. However, only about 25% of that is converted to useful energy. Thus, if we measure cars the way we measure TVs then you'd have to consider that a gallon of gasoline produces roughly 9 kWH of useful energy.

Check out novalux.com for information about laser projectors. They claim that a 65" display will consume under 200W. They are also looking to produce smaller projectors that will fit in your cell phone or iPod. Obviously these will use less than 200W.