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Benefits and drawbacks of primary versus secondary batteries
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It is difficult to compare accurately burn times/lighting durations between different manufactures hands-free lighting products since each manufacturer’s reference figures that show their product offering to have an advantage over competitive products. Some manufacturers state statistics of burn time calculated to times long after the emitted light output is useful (down to the last photon). Petzl clearly states it operates a policy whereby it ceases to consider a light effective when the lighting level (for standard hands-free lighting) decreases below 0.25 lux at a distance of 2 metres. This figure is selected as an approximate equivalence to the lux value generated on a dark night by a full moon. They consider this light output the minimum level that a hands-free lighting device should deliver in order to be fit for purpose.
Petzl operate an extensive testing procedure to produce their advertised statistics. Tests are conducted in a laboratory on five identical headtorches selected randomly straight from the production line. These headtorches are individually tested with two new sets of batteries, identical to those supplied with the product. Since temperature fluctuations can affect results (particularly the rate of discharge from battery technologies), the test environment is controlled at 20° Celsius to ensure statistically significant results. These ten sets of statistically reliable results are averaged across each parameter to provide the final definitive advertised light performance statistics. This rigorous and clearly defined testing process provides precise performance indicators, which can be effectively evaluated across various products within the range by the consumer to match their requirements against perform...
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...primary battery (especially alkaline) as they generally suffer less self-discharge when not in use than secondary batteries.
If the device operates using secondary batteries then there are significantly more potential causes of duration differentiation than standard primary batteries. In addition to the aforementioned issues that affect all batteries there are more issues that are secondary batteries specific. Issues that affect secondary batteries are:
• Cell age
• Battery cycle life
• Initial charge level
• Cell condition / past treatment
• Memory effect (especially NiCd)
• Loss of electrolyte
• Venting (a release of battery active chemicals)
These can be seen as the major reasons behind a decrease in battery life, thus burn time/light duration. Some of these issues do affect primary batteries, e.g. venting, however generally they are rechargeable only.
Table 3.2, located below, shows the battery pack characterization. The table shows the voltage of the battery and the current through the battery as a function of time.
Light sticks work in a similar way. When you “snap” a light stick, the chemical in the glass capsule mixes with a chemical in the plastic tube and creates light energy. Instead of the chemicals used by a firefly, other chemicals are used to create a glow. The light stick that you can buy at a store usually contains hydrogen peroxide, phenyl oxalate ester, and fluorescent dye (New York Times Company, 1 of 3). The light stick will glow the same color as the fluorescent dye placed in it. In luminescence, the chemical reaction “kicks an electron of an atom out of its ‘ground’ (lowest-energy) state into an ‘excited’ (higher-energy) state, then the electron give back the energy in the form of light so it can fall back to it’s ‘ground’ state (Fluorescent Mineral Society, 1 of 2).
For thousands of years, before modern electrical lighting systems were developed, candles existed not for decoration but for the sole purpose of providing artificial light in millions of homes.
Some batteries consists of harmful toxic acids and it may have threats of leakage because of its liquid state. This is called gr...
Lithium-Ion Batteries are extremely popular in the technology industry for several reasons. First off, they are much lighter then other batteries because they are made with lightweight lithium (a light and reactive metal) and carbon. Second of all, they give the most power per pound. A Lithium-Ion Battery stores 150 watt-hours per kilogram. Compare that with a Nickel-Metal Hydride Battery which only has 100 watt-hours per kilogram or a Lead-Acid Battery which only has 25 watt-hours per kilogram. There is simply no comparison, the Lithium-Ion Battery has the most watt-hours per kilogram (Howstuffworks, 2009).
I have calculated the amount of light hitting the cell by the ratio of area of the cell to the ratio of area over which light is spread: intensity = power from bulb x surface area of cell 4 pr2 The power from the bulb was worked out from the current through the bulb and voltage put across it by the power pack. An estimated efficiency of 2% was used. Outline: I varied the distance of the light source from the cell, then took readings from a voltmeter in parallel, and an ammeter in series, with the solar cell.
Lauginie, P. n.d. Drummond Light, Limelight: a Device in its Time. [e-book] Université Paris-Sud, France: Groupe d’Histoire et de Diffusion des Sciences d’Orsay (GHDSO). http://archive.ihpst.net/2013/Procs/Lauginie.pdf [Accessed: 19 Jan 2014].
For new or retrofit construction, every choice can lead to energy savings; energy that is derived primarily from fossil fuels. The typical household LED replacement for a 60w light lasts about 50,000 hours. Pretending that an incandescent could also last that long, it would consume about 3,000 kilowatt-hours (kWh) of energy whereas the LE...
Standard testing and upkeep enhances its life and improves efficiency. With the colder climate battery failure becomes far more frequent. As automobile emissions are a single of the key sources of greenhouse gases, men and women must discover ways to minimize their quantity. According to ConsumerReports.orgs Automobile Weblog, To see a map of shared outlets in a given location, drivers enter a destination. We don’t even recognize that – take the most widespread and clear issues – vehicles, golf carts, digital cameras, laptops and so many factors they all involve batteries! As the name suggests, these charges work on the power generated from the sun, which is also named solar energy. To do this you should disconnect the battery once more of course. By obtaining a single of these units you will not have to bother with that, as it will constantly maintain charging your battery for your entire fishing trip.You can also use solar trickle chargers during the winter months, so that your batteries are constantly charged u...
To understand how these lights can save money we need to look at the way they work. CFs consist of glass tubes whose inner walls are coated with a material that fluoresces when an electrical current is applied. Incandescent lights contain a filament that is heated by an electric current to the point that it glows; but the majority of energy put into the bulb produces heat, not light. The CF is more efficient at turning electrical energy into light than the incandescent bulb, and electricity costs money. Locally, Public Service charges around 6.1 cents per kilowatt‑ hour. Table I shows a comparison of three compact fluorescent bulbs with incandescent bulbs of similar light output, all made by the Philips Lighting Company. The life of the CFs is 10,000 hours, so this is the time period we will use.
Van Bree, P., Veltman, A., Hendrix, W., & Van Den Bosch, P. (2009). Prediction of battery
As the percentage of electricity generated from “green” but highly inconsistent renewable sources—such as solar or wind — increases, the availability of technology that allows us to store large amounts of electrical energy is becoming of increasing importance. One of such energy storage technologies that is showing great potential are electrochemical storage technologies- Battery Energy Storage systems (BESS). The potential application and benefit of battery storage can be seen on a limited scale in the lead-acid batteries, used in Uninterruptible Power Supplies (UPS), which is widely used to support critical electronics for short periods when there is power outage. However, these UPS batteries have relatively low energy densities, high lifecycle costs and utilize toxic materials.
Requires periodic replacement of batteries. While conventional batteries will last for 2-5 years, depending on frequency of use, the charge they may end up in the most inopportune moment. You should always have a spare set of batteries.
In general, rechargeable batteries are made of multiple cells that each consist of an anode, cathode...
In this case study I will be discussing advantages and disadvantages of electric cars. Electric cars are cars that are powered by electricity. Electric vehicles are an important part of cutting emissions and reducing global warming. The battery of an electric car stores electrical energy. The electric motor is coupled to the wheels through gears; it converts 59-60% of electrical energy into the wheels. The battery runs the motor which allows the car to move. Electric cars are necessary as they will save money, because electricity is cheaper than gas. Also electric vehicles will help reduce global warming and pollution. However, some people say that electric cars still have environmental costs. The electricity used to recharge EV batteries has to come from somewhere in the world, and now, most electricity is generated by burning fossil fuels. Although electric vehicles are classified as green cars, purists will not appreciate the toxicity of the batteries.