Electricity consumption

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To measure how much electricity a single home appliance uses: 1. We know there are ammeters, which show the amount of current used instant by instant (as a speedometer shows the speed of a car;) 2. But is there also a device that cumulates usage, the way a mileometer totals distance traveled? What would this be called? 3. And is this a $500 electrician's instrument or a $25 gadget anyone can safely use?
--
Don Phillipson
Carlsbad Springs
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For plug in appliances the kill-a-watt is pretty good. For bigger stuff you need a clamp on amp meter. Simple appliances can be pretty easy but bigger things vary more based on other factors. Like your fridge will use a lot less power while you are on vacation verses at home as well as possibly different weekday verses weekend. Heating and cooling will depend on the outside conditions.
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On Mon, 14 Mar 2011 07:17:56 -0700 (PDT), jamesgangnc

You ned more than a clamp-on ammeter to get the information the OP is requesting. You need a power meter. I had (likely still have somewhere) an old utility meter that I used to measure the amount of power consumed by the charger for my electric car.
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On 3/14/2011 8:31 PM, snipped-for-privacy@snyder.on.ca wrote:

Watt kind of electric car did you have?
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On Mon, 14 Mar 2011 21:26:52 -0400, Tony Miklos

It was a conversion of a 1975 Fiat 128L Sport coupe, running an aircraft generator for a motor, through the 4 speed tranny with a simple resistor start, dual voltage power controller with field weakening.. It started on 24 volts through a stainless steel ribbon resistor, which was then shorted out feeding full current, then switched to 48 volts with the resistor back in the circuit for about 1 second, then shorted back out. Putting the accellerator down further weakened the shunt feild of the compound wound motor, causing it to speed up. The dual voltage setup was a series parallel arrangement using a single contactor and a diode set.
8 GC2H golf cart batteries drove it about 30 miles at 50mph, or 50 miles at 30mph, on a single ($0.25 at the time) charge. That was roughly equivalent, cost-wize, to 200 MPG at 30MPH with gas at about a buck a gallon.
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On Mon, 14 Mar 2011 21:50:34 -0400, snipped-for-privacy@snyder.on.ca wrote:

Sounds cool.
Have you noticed, at least it's my impression, that when they give mpg for current hybrid cars, they totally ignore the electricity? AFAICT, they just take the miles driven and divide by the gallons of gasoline used. Or do they do it right and just not explain it?
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Hybrids are not plugged in so there is no electricity cost. The batteries are charged when the car is decelerating.
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My wife's car is the prius.
There is no savings by charging the batteries from the engine. Not to say it doesn't ever do that. You can see the charge direction when braking. They all recomend for maximum gains that you plan your stops so that you can slow down gradually. When you put your foot on the brake lightly it does the braking with the electric motor acting as a brake/generator. You can feel it. I try to do that. If you stop hard it still generates but also has to use the regular brakes. Some of the savings also comes from shutting the gas engine down when ever there is an opportunity. If you stop at a red light it will turn the engine off. When you take off the electric motor starts you moving and also starts the engine. When you are maintaining a consistent speed like out on the highway it will shut the gas engine off on slight downhills and use just the electric motor to maintain speed. It's pretty impressive that they are able to bring the gas engine in and out of the drive train without it being noticable. You really have to pay attention to tell when it happens. It pretty consistently gets around 50mpg no matter what the trip is. Even on the highway running at 75mph. I was surprised at that as the highway doesn't have much oppotunity for charging.
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jamesgangnc wrote:

The Prius has an Atkinson cycle gas engine, a major feature for high mpg. The exhaust stroke is, in effect, longer than the intake stroke. That makes the engine more efficient. But it gives you less horsepower in the same size engine. The engine has variable valve timing. I have not seen a good explanation, but I think they can shift the engine back toward a 'normal' engine for higher HP when needed. The engine HP can be smaller (as with any hybrid) because when high HP is need both the gas engine and electric motors are used. With a smaller engine you are operating in a more efficient RPM range.
It uses a "hybrid synergy drive". It is a planetary drive that connects the gas engine, 2 motor/generators, and the wheels. There is no mechanical change for forward, reverse, high, low. The "drive" allows charging the batteries while driving, powering the drive electric motor from the other motor/generator (combined with gas engine - necessary at the high end of the speed range), and generally manipulating the "drive" so the gas engine runs in the efficient RPM range. When the batteries are charged from the engine while driving, the engine is at an efficient RPM. The engine throttle is totally controlled by computer.
Regenerative braking, as above, captures much of the kinetic energy that would be lost as heat in the brakes. It must work pretty well - the city mpg is close to the highway mpg. I assume this is a major feature of all hybrids.
Obviously it all works, as you mpg indicates.
Having the engine stop at a red light is kinda strange at first.
--
bud--

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The efficiency of a gas engine varies widely with operation conditions as seen in the faster you go the more gas you use. This is the big advantage that an electric motor has as its efficiency remains relatively constant regardless of speed and operating conditions. In a gas car you waste energy every time you brake. Braking occurs obviously when you apply the brakes but also occurs every time you let up on the gas. In an electric car a lot of this brake energy especially the latter is recovered. In an electric car the motor control unit acts a a continuously variable transmission that keeps the power closely matched to the required load in a gas vehicle all you have is a few preselect ratios from the transmission to select from. Actually you only have one to select from under typical driving conditions.
Jimmie
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On Tue, 15 Mar 2011 05:14:42 -0700 (PDT), jamesgangnc

Better make that "most" hybrids are not plugged in. The VOLT is, as are several other "plug-in hybrids"
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On Tue, 15 Mar 2011 06:49:48 -0700, Smitty Two

regenerative braking puts roughly the same amount of energy back in as was required to accellerate the car to speed in the first place, or to take it up the hill if you are coming back down. Not 100%, for sure, but likely better than 75% on today's sophisticated hybrids.
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On Tue, 15 Mar 2011 17:30:52 -0400, snipped-for-privacy@snyder.on.ca wrote:

Considering the efficiency of an electric motor, I'd say 75% is *way* high. Remember, you lose energy in both directions and you can't recapture it all anyway (or there would be no need for conventional brakes).
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On 3/14/2011 11:27 PM, mm wrote:

and they don't mention that it takes more energy to CREATE the batteries and the vehicle itself than it will ever return in savings. electric cars and hybrids are a joke.
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Steve Barker
remove the "not" from my address to email
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Steve Barker wrote:

The nice thing about the concept of an electric car is that there is the possibility of eliminating the need for fossil fuel to operate it. Yes, you still need a souce of energy to provide the electricity, but that source can be derived from hydroelectric, nuclear, wind, or solar sources.
They also do not put out any pollution from the tailpipe, and are quieter.
Jon
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wrote:

I've argued that point with all kinds of conservatives and they just don't "get it"
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Maybe because you're wrong?
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On 3/15/2011 2:08 PM, snipped-for-privacy@privacy.net wrote:

What happens every time a Conservative business group tries to build a nuclear power plant or hydroelectric dam? I seem to recall a woman drowning Democrat blocking construction of an offshore wind farm because it would spoil his view of the ocean. I'm sure some left field religious group will file suit against a solar power plant because it steals the life energy from The Sun God. Tell me, how do you store the power from a wind or solar power plant in a practical manner for later use or for when there is no wind or sunshine?
TDD
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Jon Danniken wrote:

All laudable effects, but the electric car devotees are missing the point. The market for a car that only goes 80 miles on a full charge is minuscule.
My vehicle gets more than 250 miles on a tank of gas and I can "recharge" it in five minutes at any of scores of "filling stations" encountered during that 250 miles.
If someone drives 30 miles to work with the lights and A/C on, there's a good chance he won't make it home.
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wrote:

Heat and A/C are the things these electric car guys don't want to talk about.
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