9.6V, 10.8V, 12V, 14.4V, 15.6V, 18V, 19.2V, 24V, 28V, 32V, 36V – So many options. How do you go about selecting the correct voltage when buying a cordless power tool? Well, there are a few simple tips to tell you to get to the correct answer. With now a days different power tool battery type and voltage and current, you should pick the right one.
What other cordless tools would you like to have?
Take a look at what voltages those are available in. Some power tool will only be available in 12 or 14.4 versions. Others will require Li-Ion to get the full line of tools available. With so many cool tools to choose from, plan carefully for future purchases before you commit to a battery voltage and technology.
How much power do you really need?
Higher voltage will give more power. But how much power is really necessary? If you’re only drilling some pilot holes or driving screws into drywall, then power makes no difference. If you want to drill into concrete, you’ll need more power. More voltage isn’t always needed.
Do you already have other cordless tools?
If you already have some cordless tools, getting something that matches up will be useful. By doing that, you’ll end up with more batteries for each of those tools. That can be a big point and certainly something to consider. You may also think about what other people you know have, in case you borrow a tool or loan one to them. Also you know where to find the right battery for your power tool in case you run out of one.
How often will you be using this tool?
If you’re using the tool not too much, the weight may not matter much. Larger voltages are achieved by using more cells, so the batteries get much heavier as the voltage goes up. The exception is that Nickel Metal Hydride batteries are slightly lighter than Nickel Cadmium, and Lithium Ion is lighter yet. There is also the Amp Hour rating to look at. More Amp Hours means the battery will be heavier as well.
How long will you be using this tool at one time?
Are you going to be doing jobs over your head? If so, light weight is going to be important. Material will be important as well. Drilling through pine and drywall doesn’t take much. Oak and concrete takes a whole lot more. Carefully considering all of the jobs you’ll be doing will help decide what exactly you’ll be needing.
How much do you want to spend on this tool?
Lower voltages are still incredibly useful, yet the cost will be significantly lower. If you want to save on cost, 12 V or 14.4 V may be your best option. 9.6 V may even be the best option in some cases.
Just remember that buying too little could mean problems down the road with too little power. Buying too much may be too heavy and make the tool less usable in that way. Pay attention to the tool weight, battery weight and torque, then balance them so you can get what’s important to you in a tool. Keep in mind that bigger isn’t always better, so buying for the biggest numbers is pretty silly.
source:
toolbarn.com
Each one of the laptop battery we having is given a power ranking, it means how much percentage of battery is still left, the customer know about how long the battery is last long before it needs to be recharged.
These electrical terms are given using volts (V) and milliamps (mAh). (i.e.) you may see your battery is given a ranking of – 10.8V, 4000mAh.
Volts & milliamp hours are utilized for the reason that they calculate the amount of energy utilized by a laptop battery. A volt (V) is a size utilized for the amount of pressure the +ve and -ve electrodes generate in a battery during the progression of discharging energy. Amps (A) calculate the amount of resistance the energy in your battery generates in order to power a laptop.
Consider the volts & amps in terms of water tap (valve). When a tap (valve) is opened on half way, the water that flows from the pipe produces a certain amount of pressure. When you opened the tap (valve) fully, at that time the water produces more pressure in the pipe. This pressure, or power, is same as like to the volts a battery utilizes. If a laptop is running not more memory consumption programs, less power is needed to discharge energy into a laptop. Though, if a laptop is running a .vob files (i.e.) the dvd film files or other large energy consumption applications, additional power will be needed to discharge the essential amount of energy to run the dvd film.
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There are two ratings on a battery, Voltage (V) and Milliamp-hours (mAh). Voltage is the rate at which energy is drawn from a battery. Milliamp-hours represents the capacity of the battery.
- Here are some questions that might pop-up in your mind regarding your Laptop battery and answers to them:
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The “memory effect” (also known as battery effect, lazy battery effect or battery memory) can be seen in Ni-Cad and NiMH batteries. It is caused by the user continually re-charging the battery before being it has fully discharged.
It describes one very specific situation in which certain NiCd batteries gradually lose their maximum energy capacity if they are repeatedly recharged after being only partially discharged. The battery appears to “remember” the smaller capacity. The source of the effect are changes of the characteristics of the underused active materials of the cell.
is an alleged effect observed in nickel cadmium rechargeable batteries that causes them to hold less charge. The term is commonly misapplied to almost any case in which a battery appears to hold less charge than was expected. These cases are more likely due to battery age and use, leading to irreversible changes in the cells due to internal short-circuits, loss of electrolyte, or reversal of cells.
The battery will eventually ‘forget’ the unused capacity. The way to avoid the “memory effect” is to fully charge and discharge the battery at least once every month. This will ensure the battery remains healthy.
Other problems perceived as memory effect Read More…
For years scientist have been looking for cheaper and safer Lithium-ion batteries, but some researchers from Shanghai’s Fudan University have now made some progress in an area that has previously proven to be particularly tricky for battery makers. They’ve managed to create an aqueous lithium-ion battery that substitutes most of the oxygen in the battery for water, which the researchers say not only makes them less flammable, but cheap to produce.
As you might have guessed, that’s been tried before, but previous attempts have only resulted in a battery that can hold 50 percent of its charge capacity after a hundred cycles .
The new batteries, on the other hand, hang on to 90 percent of their capacity after a thousand cycles.
source:
Engadget
Li-ion batteries have quickly evolved from an R and D interest to a significant and growing fraction of the worldwide battery market. The acceptance of the technology has been driven by Its unique ability to offer a high level of performance in many aspects, including energy density, specific energy, rate capability, cycle life, and storage life, in a safe, low cost product.
As costs are reduced, the diversity of available designs increases, and performance improves, the range of applications addressed with Li-ion batteries is anticipated to increase
Further Improvements in cell performance will be made possible through both more efficient mechanical designs and improved materials. Li-ion materials are currently a subject of great interest in the Rand D community. Improved positive electrode materials that offer higher capacity. and improved safety properties are in development, as are new negative electrode matenals, such as the tin-based materials, that offer the potential for further improvement In specific energy, energy density, rate capability and longevity.
source:
The general performance characteristics of Li-ion batteries are outlined in table below.
As indicated in the table, Li-ion batteries have a high voltage, typically operating in the range of 2.5 to 4.2 V, approximately three times that of Ni-Cd or Ni-MH. As such, fewer cells are required for a battery of a given voltage. Li-ion batteries offer high specific energy and energy density, batteries with specific energy over 150 Wh/Kg and energy density over 400 Wh/L are commercially available.
Multiple-tabbed Li-ion batteries also offer high rate capability, up to 5C continuous or 25C pulse, thus high power density, and low self-discharge rate, years of calendar life, no memory effect, and a broad temperature range of operation.
Li-ion batteries can be charged from -20°C to 60°C and discharged from -40°C to 65°C. The combination of these qualities within a cost effective, hermetic package has enabled the diverse applicability of the technology.
General Performance Characteristics of Li-ION batteries
|
Characteristic
|
Performance range
|
|
|
| Operational cell voltage |
4.2 to 2.5 V |
| Specific energy |
100 to 158 Wh/kg |
| Energy density |
245 to 430 Wh/L |
| Continuous rate capability |
Typical: lC
High rate: 5C |
| Pulse rate capability |
Up to 25C |
| Cycle life at 100% DOD |
Typically 3000 |
| Cycle life at 20 to 40% DOD |
Over 20000 |
| Calendar life |
Over 5 years |
| Self discharge rate |
2 to 1O%/month |
| Operable temperature range |
-40°C to 65°C |
| Memory effect |
None |
| Power density |
2000 to 3000 W/L |
| Specific power |
700 to 1300 W/Kg |
source:
Sanyo Electric Company has announced the completion of their new factory in Hyogo, Japan, which will be the new production facility for litihum-ion rechargeable batteries made for eco-friendly vehicles.
With almost 13-billion yen invested into the 43,000 sq m plant, Sanyo will be able to produce one million cells per month to start and will increase their production scale to further meet the needs of the inevitable demand for eco-friendly vehicles.
This Japanese company has been the leading producer of Nickel-Metal Hydride (NiMH) batteries to different hybrid vehicles made by Volkswagon, Ford and Honda. Currently, Sanyo is with Volkswagon in creating a lithium-ion battery for their new hybrid cars still to come.
Sanyo has been a leader in manufacturing rechargeable battery technologies and is hoping to provide 40% of the world’s market in rechargeable automotive batteries by the year 2020.
Lithium-ion (Li-ion) batteries are comprised of cells that employ lithium intercalation compounds as the positive and negative materials. As a battery is cycled, lithium ions (Li+) exchange between the positive and negative electrodes. They are also referred to as rockingchair batteries as the lithium ions “rock” back and forth between the positive and negative electrodes as the cell is charged and discharged.
The positive electrode material is typically a metal oxide with a layered structure, such as lithium cobalt oxide (LiCo02), or a material with a tunneled structure, such as lithium manganese oxide (LiMn20 4), on a current collector of aluminum foil. The negative electrode material is typically a graphitic carbon, also a layered material, on a copper current collector. In the charge/ discharge process, lithium ions are inserted or extracted from interstitial space between atomic layers within the active materials.
The first batteries to be marketed, and the majority of those currently available, utilize LiCo02 as the positive electrode material. Lithium cobalt oxide offers good electrical performance, is easily prepared, has good safety properties, and is relatively insensitive to process variation and moisture. More recently lower cost or higher performance materials, such as LiMn20 4 or lithium nickel cobalt oxide (LiNi l _ xCox0 2), have been introduced, permitting development of cells and batteries with improved performance. The batteries that were first commercialized employed cells with coke negative electrode materials. As improved graphites became available, the industry shifted to graphitic carbons as negative electrode materials as they offer higher specific capacity with improved cycle life and rate capability.
The Li-ion battery market has grown in a decade from an R&D interest to sales of over 400 million units in 1999. Market value at the OEM level was estimated to be $1.86 billion in 2000. 1 By 2005, the market is expected to grow to over 1.1 billion units with value of over $4 billion (¥455 billion),2 while the average unit price is expected to fall 46% from 1999 to 2005.
Market interest in this cost-effective, high performance, and safe technology
has driven spectacular growth, as illustrated in Fig. 35.1. This technology has rapidly become the standard power source in a broad array of markets, and battery performance continues to improve as Li-ion batteries are applied to an increasingly diverse range of applications.
To meet market demand, an array of designs has been developed, including spiral wound cylindrical, wound prismatic and fiat plate prismatic designs in small (0.1 Ah) to large (160 Ah) sizes. Applications now addressed with Li-ion batteries include consumer electronics, such as cell phones, laptop computers, and personal data assistants, as well as military electronics, including radios, mine detectors and thermal weapons sights. Anticipated applications include aircraft, space craft, satellites, and electric or hybrid electric vehicles.
Li-ion Battery Advantages & Disadvantages:
The major advantages and disadvantages of Li-ion batteries, relative to other types of batteries, are summarized in Table below. The high specific energy ( ~ 150 Wh/kg) and energy density ( ~ 400 Wh/L) of commercial products makes them attractive for weight or volume sensitive applications.
Li-ion batteries offer a low self-discharge rate (2% to 8% per month) long cycle life (greater than 1000 cycles) and a broad temperature range of operation (charge at -20°C to 60°C, discharge at -40°C to 6S°C), enabling their use in a wide variety of applications.
A wide array of sizes and shapes is now available from a variety of manufacturers. Single cells typically operate in the range of 2.5 to 4.2 V, approximately three times that of Ni-Cd or Ni-MH cells, and thus require fewer cells for a battery of a given voltage.
Li-ion batteries can offer high rate capability. Discharge at 5C continuous, or 25C pulse, has been demonstrated.
The combination of these qualities within a cost effective, package has enabled diverse application of the technology.
Advantages & Disadvantages of Li-ion battery
|
|
Advantages
|
Disadvantages
|
| Sealed cells; no maintenance required |
Moderate initial cost |
| Long cycle life |
Degrades at high temperature |
| Broad temperature range of operation |
Need for protective circuitry |
| Long shelf life |
Capacity loss or thermal runaway when over-charged. |
| Low self-discharge rate |
Venting and possible thermal runaway when crushed |
| Rapid charge capability |
Cylindrical designs typically offer lower power density than Ni-Cd or
Ni-Mh |
| High rate and high power discharge capability |
|
| High coulombic and energy efficiency |
|
| High specific energy and energy density |
|
| No memory effect |
|
A disadvantage of Li-ion batteries is that they degrade when discharged below 2 V and may vent when overcharged as they do not have a chemical mechanism to manage overcharge, unlike aqueous cell chemistries.
Li-ion batteries typically employ management circuitry and mechanical disconnect devices to provide protection from over-discharge, overcharge or over temperature conditions. Another disadvantage of Li-ion products is that they permanently lose capacity at elevated temperatures (65°C), albeit at a lower rate than most Ni-Cd or Ni-MH products.
Source:
Needbattery.com
We can see laptops every where, they’re becoming more and more popular as they are light, portable and personal to each of us. It is like they are nondetachable part of our daily life.
But behind every Laptop is lying the power source which runs everything from CPU to DVD Rom, laptop battery at the edge of technology which is getting thinner, more powerful and easier to handle everyday thanks to improvements and researches have been made.
But do we know enough about them? How to charge-discharge them, how long they will run our laptop and when is the time to replace them…
These articles will help you get a better understanding of a laptop battery and it’s functionality:
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Does using the wireless network card drain a laptop battery?
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