What should I consider when buying a notebook for university?
This is a common problem every summer, so a broad answer may help some people. There are many things that need to be considered, including course requirements, use scenarios (portability, ergonomics, etc.), user experience, support and backup strategies and budgets.
In most cases, a laptop will be the best answer, but many students use more than one device. A full “educational IT” system could include a smartphone, a tablet, a laptop and a USB backup drive, plus a laptop riser or docking station with an external keyboard and mouse.
On course for uni
Ask your granddaughter to check with her university department to see what kind of software she will need, whether there are any special requirements for her course and whether student discounts are available. In many cases, any PC will do. However, some students need to run professional software from AutoCAD, Adobe, Microsoft and other suppliers, and some will need to run sophisticated modelling or statistical software.
Students on general courses might be able to get by with low-end hardware such as a tablet, a cheap Windows 10 laptop or even a Chromebook. Students on technology, engineering, programming and other courses may need a powerful PC with at least 8GB or 16GB of memory. This will obviously cost more.
Also, ask your granddaughter to seek advice from students who are currently doing the same course. She may even know girls who left her school last year, or the year before, who are now doing the same course at the same university.
What’s the use?
The most important questions are: where is your granddaughter going to work, and how much portability does she need?
There is generally a trade-off between screen size, weight, battery life and price.
If she is going to use her laptop in her room, she might be happy with a heavy laptop with a 15.6in or even a 17.3in screen. If she is going to carry it around all the time, she will want something small and light with good Hp 484170-001 laptop battery life. Today, this usually means a laptop or 2-in-1 with an 11.6in screen and a solid-state drive(SSD) instead of a traditional hard drive.
One strategy would be to buy a laptop or desktop PC to use in her room, and a small tablet or large smartphone for use on campus. There are plenty of portable keyboards that work well with tablets and smartphones. I use a Microsoft Universal Mobile Keyboard – a cheap deal from Amazon – but there are alternatives from Microsoft, Logitech, and many other suppliers.
Different people like to work in different ways, and your granddaughter may already know what will suit her, based on her sixth-form experience.
However, I still take handwritten notes during “lectures” (press conferences etc) because I find it more effective than using a laptop. Some academic research supports this approach.
What does she use now?
Since your granddaughter is old enough to go to university, she probably has at least a decade’s worth of experience with PCs, and perhaps half a decade’s experience of smartphones and tablets. She may well be a very proficient user. If so, you should buy something that supplements or improves on whatever she has now.
I usually recommend against switching away from a familiar system, because it sacrifices hard-earned experience. The transition may be painful, and often there are few real advantages, if any. All the main platforms – Windows, MacOS, Linux, Apple iOS, Android etc – have their fans and their detractors, but they all have tens or hundreds of millions of users. Some have more than a billion.
Most educational and business software runs on Microsoft Windows, and such software might be a course requirement. However, if your granddaughter is an Apple Macintosh user now, I’d recommend sticking to it.
If your granddaughter already has a laptop, aim to double the specification. Try to buy something with twice the memory, more or faster storage (ie, an SSD), and a faster processor. You probably won’t be able to run any speed tests, but you can read reviews online. If in doubt, aim for a laptop with a recent (sixth or seventh generation) Intel Core i5, or at worst a Core i3-6100.
This may be overkill in your granddaughter’s case, but it’s better to have too much power than too little.
Efficient businesses work out how much money they’ll save by buying faster PCs, because they know the value of wasted time (based on hourly rates and other employment costs, such as rent and rates). I’ve not seen anyone do the maths for students paying £9,000 a year plus subsistence costs for a 40-hour working week, but a decent laptop is a small part of the total cost of getting a degree. (Well, £1,000 is 2% of £50,000. On that basis, I’d spend at least £500.)
Purchase and support
Computers are great until they go wrong. I often suggest HP or Dell laptops because you can buy them online with three years of reasonably priced on-site service. Also, both companies sell professional quality business machines, and getting a university degree is a serious business nowadays. If buying a Mac, buy AppleCare and try to live close to an Apple Store.
Tier1 Online, which sells second-hand business class laptops such as IBM ThinkPads, often sells three-year warranties, but not with on-site service. I particularly like the X220 and Carbon X1 models.
Student computers can also get stolen, so insurance is another consideration.
Worst of all is the prospect of losing a term paper with a deadline looming. It’s essential to have backup copies. I often make multiple backups by saving to an online cloud drive (OneDrive, Google Drive, Dropbox etc), saving copies on USB thumb drives and external hard drives, and emailing myself unfinished articles. A long article may well be worth more than the laptop it’s written on.
The Best Refurbished Notebook Deals Right Now
A refurbished model might be a good choice if you want to save some money on your next laptop purchase. If you buy from a reputable seller, the refurbished model should be in great condition and guarantee the warranty. However, not all refurbished goods are much cheaper than new equivalents. You need to pull the trigger and do some research.
Below, we’ve identified the best refurbished laptop deals right now. For help finding a unit on your own, read our refurbished laptop buying guide. If you prefer your laptop brand new, make sure to check our best laptop deals page.
How To Double Laptop Battery Life
Anyone who uses a laptop on a plane likes a battery that can fly across the United states. Now Intel researchers believe they can double the battery life of a laptop without changing the battery itself. Instead, they will optimize system wide power management, including operating systems, screens, mice, motherboards, chips, and devices connected to the USB ports.
To be sure, manufacturers and researchers have been exploring piecemeal ways to make portable computers more energy efficient. Operating systems are designed to deploy power-saving screen savers and put an entire system to sleep if its owner hasn’t used it after a while. And Intel’s forthcoming Atom, a microprocessor for mobile Internet devices, can be put to sleep at up to six different levels, depending on the types of tasks that it needs to do.
But the problem with these approaches is that they’re not coordinated across the entire device. Intel’s prototype power-management system is aware of the power that’s used by all parts of a laptop, as well as the power requirements of a person’s activity, and it shuts down operations accordingly, says Greg Allison, business development manager. The project, called advanced platform power management, was demonstrated on Wednesday at an Intel event in Mountain View, CA.
Allison gives this example: today, when a person reads a static e-mail, the screen still refreshes 60 times a second, and peripherals such as the keyboard, mouse, and USB devices drain Hp pavilion dv4 laptop battery power while awaiting instructions. “We’re burning energy even when we don’t need to,” Allison says. In this situation, Intel’s system would save power by essentially taking a snapshot of the screen that a person is reading and saving it to a buffer memory. So instead of refreshing, the screen would maintain an image until a person tapped a button on the keyboard or moved the mouse (the keyboard and mouse would also stay asleep until activated).
All the while, the operating system will be monitoring use of other applications, restricting operations to those that aren’t being actively used. And if there are any devices plugged into a USB port, such as a flash-memory stick, the system would put them to sleep. At the same time, explains Allison, energy-monitoring circuits on Intel chips will put unnecessary parts of the microprocessor to sleep. It takes 50 milliseconds for the entire system to spring to life, he says, a length of time imperceptible to the user.
Intel isn’t the first to think of the idea of integrating power-saving technology throughout a device. One Laptop per Child (OLPC), the nonprofit that builds inexpensive, rugged laptops meant for children in the developing world, set the standard with a gadget that consumes one-tenth of the power of a conventional laptop. Granted, OLPC’s laptop doesn’t have the capabilities of consumer machines, but it does show what is technically achievable.
There are definitely advantages to this systemic approach, says Seth Sanders, a professor of electrical engineering and computer science at the University of California, Berkeley. “Comprehensively looking through the system at all of the different pieces that are cycling unnecessarily provides an opportunity [for power savings],” he says.
Allison says that the company is already talking with operating-system vendors to explore what it would take to integrate this approach into software. And as a major contributor to the new USB 3.0 standards, Intel will have some say in how much power forthcoming USB devices will use. In addition, Allison says, the company is trying to secure deals with display and hardware vendors. “This won’t happen in the next three years,” he says. But he suspects that pieces of the new power-management system will find their way into laptops within five years.
The best notebooks to buy in 2017
Choosing a winner to buy a new laptop isn’t easy. Finding a balance between the right price and the right price can be daunting.
Due to the range of models, operating systems and constant updates it can be hard to choose the right system that is going to last.
With so much choice just a few clicks away, The Telegraph has broken down some of the main questions you should be asking when making a purchase and selected some of the best laptops, notebooks and Chromebooks you can buy, from the top performers to those which won’t break the bank.
What kind of laptop do I need?
Even before you get down to the details it helps to know what sort of device you are looking for.
Do you need your device for the home or on the move? Will you only use it for email and web browsing? Will you want to stream videos or play video games?
For something cheap and portable a smaller Chromebook or laptop with low weight and a screen of around 11 inches would work, such as the Acer Chromebook R11 or the HP Steam 11. Both of these will set you back under £250, although sacrifice power and storage capacity.
If you are using your laptop for email, typing documents or using the internet you may only need to spend a few hundred pounds, while you may need to spend a little more to stream videos to a higher quality.
For gaming you will need a more powerful device with a quality graphics card. The Dell Inspiron 15 7000 Gaming is at the cheaper end of the scale for this, more expensive brands can cost thousands of pounds.
And if you demand the highest specifications for video or photo editing you may want to look to a powerful MacBook.
A number of laptops are now also ‘two-in-one’ devices, that can act as a tablet by detaching from the keyboard. Other laptops also feature touchscreens with stylus pens, such as the Lenovo Yoga Book or the Microsoft Surface Laptop.
Do I want a Windows laptop, MacBook or Chromebook?
Current devices broadly run on three different operating systems that run on the three main varieties of laptop:
Windows 10
These are some of the most common devices and run Microsoft’s Windows operating system. They are able to perform some of the widest ranging tasks and also have the greatest variety in models, brands and pricing. Microsoft has also recently released Windows 10 S, which is designed to compete with ChromeOS, limiting some apps and downloads.
Pros: Commonly used, greatest access to programs and apps, best for gaming
Cons: Considered more vulnerable to viruses
MacBook
The MacBook Pro, MacBook and MacBook Air are all Apple laptops running on macOS. They are generally seen as powerful, smooth and highly reliable.
Pros: Best for high performance use of creative software, connectivity to other Apple products and services
Cons: Limited access to some programs, expensive
Chromebook
Google’s ChromeOS used on Chromebooks is largely limited to online use, essentially operating like a web browser. Rather than installing programs users access them through Google’s Chome Web Store. They have limited storage capacity, but are fast and inexpensive.
Pros: Cheap, fast, user friendly
Cons: Largely limited to online use and Google applications
How much do I want to spend?
The most important consideration to many buyers is cost; a low price doesn’t always have to mean sacrificing performance if your laptop can still run the tasks you need.
Nowadays you can pick up a cheap laptop or Chromebook for less than £250. You will be quite limited in terms of performance on a laptop, although you could get a decent Chromebook for around that price.
For between £500 and £750 you should be expecting at least an Intel Core i5 processor with 8GB of RAM or better, which will perform more complicated tasks faster.
Spending £1,000 and up you would be looking at a premium product sporting the latest generation of Intel Core i5 or i7 processors. You would want this for high intensity work such as video editing or gaming. A recent price surge from some Apple products and others has pushed more top laptops into this bracket.
What else to consider
- Screen size: Obviously a smaller screen means a smaller laptop, increasing its portability. Larger screen models will also need high resolution to create the perfect picture, but can be better if you want a more accessible screen or want to open lots of tabs.
- Weight: If you plan to lug your laptop to classes or work, you may want something that weighs 1.5kg or less. If it is going to sit on your desk most of the day you can always go for a bulkier model, which may be cheaper than a sleek ultrabook.
- Battery life: If you’re going to be using your laptop at your desk for most of the time, battery life will be less of an issue, but if you work on the go or in a coffee shop, you don’t want to get caught without power at a crucial moment. Some dedicated gaming laptops may only last four hours when under strain, while ultraportables can manage 12 hours or better.
Under £500
Best for Windows on a budget: Acer Swift 3
Screen: 14 inches
Weight: 1.5kg
Battery life: 10 hours
For a Windows-running performer, the Acer Swift 3 has the feel of a pricier laptop for under £500, with its smooth aluminium case reminiscent of more up-market devices.
The most basic model has an Intel i3 processor with an 128GB SSD and 8GB of RAM, enough for most daily tasks. Other features include a backlit keyboard and fingerprint scanner, and the Swift 3 is fairly connection-friendly with HDMI, USB and USB-C.
The drawbacks are largely limited to screen brightness. Improved processors will set you back another £250, although that is still great value for a solid device.
Also consider: Lenovo Yoga 510 2-in-1 (£379)
Best for practicality: HP Chromebook 14
Screen: 14 inches
Weight: 1.7 kg
Battery life: 9.25 hours
For a bigger screen Chromebook this HP is a useable device at a reasonable price. The HP Chromebook 14 lacks some of the flashy touch screens of the latest generation, but comes with plenty of practical features including three USB ports, an SD card slot and HDMI connection.
In addition, the 1920×1080 screen resolution will provide a crisp, quality picture. This larger Chromebook will easily see you through most routine tasks.
Also consider: Acer Chromebook 15 (£239.99)
Best for simple stuff: Acer Chromebook R11
Screen: 11.6 inches
Weight: 1.25 kg
Battery life: 12 hours
At the cheaper end of the market, the Acer ChromeBook R11 comes in at less than £250 and looks good with a crisp white finish and aluminium top panel.
The R11 features a stylish touchscreen with 360 degree rotation, although the resolution is a little low at 1366 x 768 pixels it will look fine on the smaller screen. A solid Acer as07b31 laptop battery life with its slimmer size and portability make this ideal for use on-the-go.
Also consider:Asus Chromebook Flip (£208.32)
Under £1,000
Best-looking Windows laptop: Surface Laptop
Screen: 13.5 inch
Weight: 1.25 kg
Battery life: up to 14.5 hours
Microsoft’s new Surface Laptop is an attempt to “reset the category”. There’s no doubt it is an excellent device, with excellent battery life, a slim build and a unique Alcantara fabric keyboard, that feels almost warm to touch. It’s also without doubt the most beautiful Windows device this year.
Drawbacks include the fact this laptop is built to run on Windows 10 S, Microsoft’s new operating system that limits access to some apps. It should mean the laptop runs better in the long-run, but this has yet to be tested. The entry level model also comes with just 4GB of RAM, quite low for this price point.
Best for reliability: MacBook AirScreen: 13.3 inch
Weight: 1.35 kg
Battery life: 12 hours
It has been two years since the last update to the MacBook Air, with many predicting a phase-out due to the launch of the new MacBook Pro in 2016. However, the Air remains the most affordable Apple notebook you can buy, all the more important given recent jumps in Apple prices.
Like most Apple products it is known for a battery life that lives up to expectations, in this case around 12 hours. The laptop also still retains traditional USB slots, unlike more recent Apple updates. While it remains a solid buy, it could be outshone by the upcoming Microsoft Surface Laptop (released in June).
Best Apple alternative: Lenovo IdeaPad 710s
Screen: 13.3 inch
Weight: 1.1 kg
Battery life: 8 hours
A rival to the MacBook Air, the Lenovo IdeaPad 710s has been noted for its similarity in design to Apple’s cheapest model, matching its aluminium bodywork . As a cheaper alternative, the IdeaPad 710s now comes in at around £200 cheaper with an Intel Core i5-7200U processor. It is also thinner (at 14mm) and lighter than the Air.
With a display that can rotate to 180 degrees it is also flexible, but on battery life it is not as competitive as some other brands.
Also consider: Asus Zenbook UX310 (£600)
Best for gaming for less: Dell Inspiron 15 7000 Gaming
Screen: 15.6 inches
Weight: 2.65kg
Battery life: Up to 10.5 hours
If you are not willing or unable to spend thousands of pounds on a gaming laptop, the Dell Inspiron 15 7000 Gaming is a decent backup option. It is not going to outrun the high end machines, but for casual gaming you’ll get the performance you need.
The cheapest model comes in at under £1,000, which is a steal for a gaming ready device. The design includes Ethernet, SD, HDMI and USB ports and comes in a smart black and red finish.
Also consider: MSI GL62 (£949.97)
Best for standing out: Lenovo Yoga Book
Screen: 10.1 inch
Weight: 0.689 kg
Battery life: 15 hours
A stunning laptop/tablet hybrid launched last year, the Lenovo Yoga Book features an innovative keyboard and touchpad that stand out from the latest generation of devices.
The Yoga Book features no physical keyboard, instead presenting a virtual one which only switches on when you start using it. As well as a touch screen, the Yoga Book pushes itself as a device you can really write on, clipping a notepad over the virtual keyboard sees notes and drawings transmitted onto the main screen.
While it’s an exciting offering at a low price, the keyboard is considered tricky to get used to, but the overall product is light, portable, and certainly something different.
Money no object
Best all-rounder: Dell XPS 13
Screen: 13.3 inches
Weight: 1.29kg
Battery life: 13 hours
The highly rated Dell XPS 13 is considered the lead challenger to the MacBook Pro. The XPS 13 features a virtually borderless 13.3 inch Infinity Edge display, which is available with touch.
Dell also claims the laptop offers up to 22 hours of Dell Xps m1330 Notebook Battery life, although in practice this is more like 12 to 13 hours when streaming video. The latest models also run on Kaby Lake processors, Intel’s newest and more powerful seventh generation processor.
Without the touch display you could currently pick up the new model for £1,149, but with it included the XPS 13 will set you back £1,279. The main drawback is an awkwardly placed webcam, sitting to the bottom left of the screen.
Also consider: HP Spectre 13 (£1,149.95)
Best for Apple addicts: MacBook Pro
Screen: 13.3 inches
Weight: 1.37kg
Battery life: 10 hours
Coming four years after Apple’s last high-end laptop, the latest MacBook Pro is thinner, more powerful and features innovations not seen on other laptops, such as its ‘Touch Bar’ and a Touch ID fingerprint scanner. The Touch Bar offers shortcuts and replacing function keys, but is not supported on many apps just yet.
And the new edition has done away with some staple features, dropping support for standard USB sticks and SD cards, meaning you may have to buy new dongles or wires for its USB-C ports. Following a 2017 refresh to its range, models with the Touch Bar and fingerprint scanner will set you back £1,749, while the price of the standard 13-inch model has dropped to £1,249.
The new MacBook Pro remains the top performing device for Apple lovers, with a beautiful screen, exquisite ‘butterfly’ keyboard and easy-to-use trackpad.
Also consider:Macbook 12-inch (£1,249)
Best for versatility: Microsoft Surface Book
Screen: 13.5 inches
Weight: 1.6 kg
Battery life: 12 hours
Microsoft’s first ever laptop launched in the UK last year and the Surface Book features a detachable 13.5 inch display and highly flexible hinge which gives Microsoft’s “ultimate laptop” the added versatility of a tablet.
The Surface Book has Microsoft calls a ‘dynamic fulcrum hinge’ connecting the keyboard and display to hold the heavier screen in place, since it holds all the parts to operate as a tablet.
The keyboard can also hold an optional discrete GPU, or graphics processor, which gives the laptop added power. This does add to the weight and top end price, and the Intel Core i5 model with the discrete GPU costs around £400 more.
How To Get The Best Battery Life From Your Notebook
Look at our most important technique to get your laptop to get the most out of the plugin; all of the things we use from screen brightness to WiFi card.
Reduce Your Screen Brightness
The most notable consumer of power in a notebook computer is the screen. Notebook makers have alleviated this somewhat in recent years by switching from CCFL backlighting units to LED, but the fact remains.
First, here’s how to adjust your screen brightness in Windows 7 and 8/8.1:
- In the system Tray, click the power plug/battery icon
- When the pop-up appears, click More power options
- The next screen will show you the available power plans; the one that’s currently selected will be bolded. Click the Change plan settings link next to it
- Now you’re looking at settings specific to your current power plan. The power plan has different settings depending on whether you’re using Dell Studio 1557 AC Adapter or on battery. Move the Adjust plan brightness slider to the desired position for On battery mode and then click the Save changes button to apply your settings.
We suggest you begin by moving the slider all the way to the left (minimum brightness) for the On battery settings and moving it up bit by bit until it’s comfortable. Remember to keep the brightness as low as you can because even reducing screen brightness by 10 percent can significantly extend how long your notebook lasts unplugged.
One brightness setting will not fit all situations; you may have to increase the brightness in a sunlit room to make the screen usable, for example.
For the best results, consider setting up your own customized power plan using our guide here.
Avoid Resource-Intensive Activities
Two other leading consumers of electric power in a notebook computer are the processor (CPU; Central Processing Unit) and the graphics card (GPU; Graphics Processing Unit). The processors and graphics cards used in notebook computers are specially designed to be most efficient at lower power states; they can throttle back their operating frequency (GHz) and voltage to very low levels. They’re only able to do this however when the user is not running strenuous activities that require significant processing power. Strenuous activities include but aren’t limited to the following:
- Photo and video editing
- Playing video games including 3D and Flash/browser-based games
- Playing video, especially HD
The CPU and/or GPU will use more power while performing the activities above. Here are examples of activities that require very little processing power for modern computers:
- Web browsing (standard; non-Flash-based websites)
- Word processing
- Music playback
In other words, try to plan what you’re going to do on your notebook in advance while on battery.
Stay Close to a Wireless Access Point
Using wireless Internet in general has a very small effect on Dell studio 1537 laptop battery life; it can have a much greater effect however if you are at the edge of the wireless router’s signal range. The wireless icon in the system tray uses a five bar indicator to show signal strength; ideally this will be at least three if not four or five (ideal). The computer is working extra hard to maintain the wireless connection if the signal strength is at one or two bars, especially if it has to reconnect often.
Another Internet-related activity that can have a significant effect on battery life is downloading large files; consider downloading these while you’re plugged into AC power. Transmitting and receiving large amounts of data uses much more power than simple web browsing.
For a detailed analysis on how wireless card usage affects battery life, take a look at our technical analysis here.
Turn off Keyboard Backlighting
Many modern notebooks have backlit keyboards; these can be turned off to save battery life typically through keyboard commands (see your notebook’s owner’s manual). At the very least, turn the brightness down a notch or two (if applicable; some backlit keyboards have variable brightness levels).
Conclusion
We reviewed several important concepts pertaining to battery life in this article. The display is arguably the largest consumer of power and it’s therefore important to keep that at a minimum; we also reviewed the impact of running resource-intensive activities such as games on battery since they require more processing power. Next we analyzed why it’s important to stay close to a wireless router (if you’re using the Internet) and to avoid downloading large files. Lastly we looked at turning down keyboard backlighting (or turning it off completely) to squeeze as much as possible out of the battery.
How to extend lithium-based batteries?
Discover what causes Li ion age and battery users to extend its life.
The research of batteries is mainly concentrated in lithium. There are too many chemical substances. You can imagine that the future lies in the lithium battery. We have reasons to be optimistic about lithium ion in many ways better than other chemistry. More and more applications and intrusions into the market have been carried out with lead acid solid, such as backup and load balancing. Many satellites are powered by Li ion.
Lithium-ion has not yet fully matured and is still improving. Notable advancements have been made in longevity and safety while the capacity is increasing incrementally. Today, Li-ion meets the expectations of most consumer devices but applications for the EV need further development before this power source will become the accepted norm.
What Causes Lithium-ion to Age?
The lithium-ion battery works on ion movement between the positive and negative electrodes. In theory such a mechanism should work forever, but cycling, elevated temperature and aging decrease the performance over time. Manufacturers take a conservative approach and specify the life of Li-ion in most consumer products as being between 300 and 500 discharge/charge cycles.
Evaluating battery life on counting cycles is not conclusive because a discharge may vary in depth and there are no clearly defined standards of what constitutes a cycle. In lieu of cycle count, some device manufacturers suggest battery replacement on a date stamp, but this method does not take usage into account. A Acer as07b31 laptop battery may fail within the allotted time due to heavy use or unfavorable temperature conditions; however, most packs last considerably longer than what the stamp indicates.
The performance of a battery is measured in capacity, a leading health indicator. Internal resistance and self-discharge also play roles, but these are less significant in predicting the end of battery life with modern Li-ion.
Figure 1 illustrates the capacity drop of 11 Li-polymer batteries that have been cycled at a Cadex laboratory. The 1,500mAh pouch cells for mobile phones were first charged at a current of 1,500mA (1C) to 4.20V/cell and then allowed to saturate to 0.05C (75mA) as part of the full charge saturation. The batteries were then discharged at 1,500mA to 3.0V/cell, and the cycle was repeated. The expected capacity loss of Li-ion batteries was uniform over the delivered 250 cycles and the batteries performed as expected.
The following tables indicate stress related capacity losses on cobalt-based lithium-ion. The voltages of lithium iron phosphate and lithium titanate are lower and do not apply to the voltage references given.
Although a battery should deliver 100 percent capacity during the first year of service, it is common to see lower than specified capacities, and shelf life may contribute to this loss. In addition, manufacturers tend to overrate their batteries, knowing that very few users will do spot-checks and complain if low. Not having to match single cells in mobile phones and tablets, as is required in multi-cell packs, opens the floodgates for a much broader performance acceptance. Cells with lower capacities may slip through cracks without the consumer knowing.
Similar to a mechanical device that wears out faster with heavy use, the depth of discharge (DoD) determines the cycle count of the battery. The smaller the discharge (low DoD), the longer the Acer as07b72 battery will last. If at all possible, avoid full discharges and charge the battery more often between uses. Partial discharge on Li-ion is fine. There is no memory and the battery does not need periodic full discharge cycles to prolong life. The exception may be a periodic calibration of the fuel gauge on a smart battery or intelligent device.
Table 2 estimates the number of discharge/charge cycles Li-ion can deliver at various DoD levels before the battery capacity drops to 70 percent. DoD constitutes a full charge followed by a discharge to the indicated state-of-charge (SoC) level in the table.
Most Li-ions charge to 4.20V/cell, and every reduction in peak charge voltage of 0.10V/cell is said to double the cycle life. For example, a lithium-ion cell charged to 4.20V/cell typically delivers 300–500 cycles. If charged to only 4.10V/cell, the life can be prolonged to 600–1,000 cycles; 4.0V/cell should deliver 1,200–2,000 and 3.90V/cell should provide 2,400–4,000 cycles.
Lithium-ion suffers from stress when exposed to heat, so does keeping a cell at a high charge voltage. A battery dwelling above 30°C (86°F) is considered elevated temperature and for most Li-ion a voltage above 4.10V/cell is deemed as high voltage. Exposing the battery to high temperature and dwelling in a full state-of-charge for an extended time can be more stressful than cycling. Table 3 demonstrates capacity loss as a function of temperature and SoC.
On the negative side, a lower peak charge voltage reduces the capacity the battery stores. As a simple guideline, every 70mV reduction in charge voltage lowers the overall capacity by 10 percent. Applying the peak charge voltage on a subsequent charge will restore the full capacity.
In terms of longevity, the optimal charge voltage is 3.92V/cell. Battery experts believe that this threshold eliminates all voltage-related stresses; going lower may not gain further benefits but induce other symptoms.Table 4 summarizes the capacity as a function of charge levels. (All values are estimated; Energy Cells with higher voltage thresholds may deviate.)
Most chargers for mobile phones, laptops, tablets and digital cameras charge Li-ion to 4.20V/cell. This allows maximum capacity, because the consumer wants nothing less than optimal runtime. Industry, on the other hand, is more concerned about longevity and may choose lower voltage thresholds. Satellites and electric vehicles are such examples.
For safety reasons, many lithium-ions cannot exceed 4.20V/cell. (Some NMC are the exception.) While a higher voltage boosts capacity, exceeding the voltage shortens service life and compromises safety. Figure 5 demonstrates cycle count as a function of charge voltage. At 4.35V, the cycle count of a regular Li-ion is cut in half.
Besides selecting the best-suited voltage thresholds for a given application, a regular Li-ion should not remain at the high-voltage ceiling of 4.20V/cell for an extended time. The Li-ion charger turns off the charge current and the battery voltage reverts to a more natural level. This is like relaxing the muscles after a strenuous exercise.
Figure 6 illustrates dynamic stress tests (DST) reflecting capacity loss when cycling Li-ion at various charge and discharge bandwidths. The largest capacity loss occurs when discharging a fully charged Li-ion to 25 percent SoC (black). Cycling between 85 and 25 percent (green) provides a longer service life than charging to 100 percent and discharging to 50 percent (dark blue). The smallest capacity loss is attained by charging Li-ion to 75 percent and discharging to 65 percent. This, however, does not fully utilize the battery. High voltages and exposure to elevated temperature is said to degrade the battery quicker than cycling under normal condition.
What Can the User Do?
Environmental conditions, not cycling alone, govern the longevity of lithium-ion batteries. The worst situation is keeping a fully charged battery at elevated temperatures. Battery packs do not die suddenly, but the runtime gradually shortens as the capacity fades.
Lower charge voltages prolong battery life and electric vehicles and satellites take advantage of this. Similar provisions could also be made for consumer devices, but these are seldom offered; planned obsolescence takes care of this.
A laptop battery could be prolonged by lowering the charge voltage when connected to the AC grid. To make this feature user-friendly, a device should feature a “Long Life” mode that keeps the battery at 4.05V/cell and offers a capacity of about 80 percent. One hour before traveling, the user requests the “Full Capacity” mode to bring the charge to 4.20V/cell.
The question is asked, “Should I disconnect my laptop from the power grid when not in use?” Under normal circumstances this should not be necessary because charging stops when the Li-ion battery is full. A topping charge is only applied when the battery voltage drops to a certain level. Most users do not remove the AC power, and this practice is safe.
Modern laptops run cooler than older models and reported fires are fewer. Always keep the airflow unobstructed when running electric devices with air-cooling on a bed or pillow. A cool laptop extends battery life and safeguards the internal components. Energy Cells, which most consumer products have, should be charged at 1C or less. Avoid so-called ultra-fast chargers that claim to fully charge Li-ion in less than one hour.
How to Check the Charge of a Dell Notebook’s Battery
Do you have a DELL laptop, but you don’t know how much it costs Can’t I open my laptop? Are you going out for a taxi? It will help you to finish the task!
IPad Pro VS.MacBook: which one should you buy?
“Should I buy a iPad Pro or an MacBook?”” For Apple fans, it was a tough decision, since the initial announcement of iPad Pro. The new iPad, Pro, and a series of MacBook updates make this tricky decision even more difficult, especially the powerful iOS 11 road.
The new iPad Pro models get a boost in size and processing power, with a 10.5-inch tablet replacing the 9.7-inch base model, and a step up to the new A10X Fusion chip. On the other hand, the MacBook line gets Intel’s latest, 7th Generation Kaby Lake processors and will receive a new operating system: macOS High Sierra. This OS brings expanded capability and performance to the laptops.
From portability to pricing, several key distinctions between the laptop and tablet will affect your ability to work on either device, but Apple has pushed hard to narrow the gaps between these very different devices.
| iPad Pro | Macbook 12-inch | Macbook Pro 13-inch | |
| Starting Price | 10.5-inch – $64912.9-inch – $799 | 1299 | $1,299 $1,799 with Touch Bar |
| Operating System | iOS 10 | macOS Sierra | macOS Sierra |
| Processor | A10X Fusion | up to 1.4 GHz Intel Core i7 processor | up to 3.5 GHz Intel Core i7processor |
| Memory | 4GB | 8GB 16GB | 8GB 16GB |
| Graphics | Integrated 12 core GPU | Intel HD Graphics 615 | Intel Iris Plus Graphics 640 |
| Storage | 64GB 256GB 512GB | 256GB SSD 512GB SSD | 128GB SSD 256 512 1TB SSD |
| Ports | Lightning Port | USB-C | 2x Thunderbolt 3 (USB-C) |
| Display Size | 10.5 inches 12.9 inches | 12 | 13.3 |
| Display Resolution | 10.5-inch – 2224 x 1668 12.9-inch – 2732 x 2048 | 2304 x 1440 | 2560 x 1600 |
| Touch | Touch Screen Touch IDApple Pencil ($99) | Force Touch trackpad | Force Touch trackpadTouchBar(available without) |
| Keyboard | Smart Keyboard – 10.5-inch ($159) Smart Keyboard – 12.9 inch ($169) | Full-size backlit keyboard | Full-size backlit keyboard |
| Cameras | 7-megapixel FaceTime camera 12-megapixel rear-facing camera | 480p FaceTime camera | 720p FaceTime HD camera |
| Dimensions | 10.5 inch – 9.8 x 6.8 x 0.2412.9-inch – 12 x 8.68 x 0.27 | 11.04 x 7.74 x 0.52 | 11.97 x 8.36 x 0.59 |
| Weight | 10.5-inch – 1.03 (Wi-Fi) / 1.05 (Wi-Fi + Cellular)12.9-inch – 1.49 (Wi-Fi) / 1.53 (Wi-Fi + Cellular) | 2.03 | 3.02 |
Which Is Right for You?
While the two styles of device have gotten more and more alike over the years, the central questions have stayed the same: Do you need productivity, performance or portability? Flexibility with inputs or more ports and storage? Budget-friendly pricing or the best tool for the money? Where you land on these questions will come down to your needs and preferences, but for getting things done, the MacBook Pro is our recommendation.
| iPad Pro | MacBook (12-inch)
MacBook Pro (13-inch) |
|
| Size and Portability | ✔ | |
| OS and Office Capability | ✔ | |
| Input and Interaction | Draw | Draw |
| Cameras | ✔ | |
| Storage and Ports | ✔ | |
| Price | ✔ |
The MacBook Pro wins the productivity battle thanks to its broad compatibility, capable OS, Powerful Apple a1278 laptop battery,full feature set and range of configuration options. When you need a no-nonsense machine for even demanding office work, the MacBook Pro is the go-to choice.
Still, the iPad Pro offers several distinct features that the MacBook simply can’t match, like touch and pen input and excellent portability. While we might recommend using the iPad Pro as a secondary device, there’s a strong argument that it’s the better choice for professionals who work outside of the office or creatives who need drawing and handwriting input.
U.S. considers expanding a notebook ban as lithium battery fires increase
As the U.S. government considers expanding the ban on laptops and other electronic equipment in commercial aircraft cabins, federal data show that storing such equipment in the cargo compartment of the aircraft may increase the risk of fire.
Federal Aviation Administration statistics indicate that airplane fires involving lithium batteries are on the rise.
In 2014, the FAA reported that such TOSHIBA PA3757U-1BRS Laptop Batteries were responsible for nine fires, extreme heat or smoke on cargo and passenger planes. That number grew to 16 in 2015; 31 in 2016 and 17 in the first five months of 2017.
Most of the fires or overheated devices were doused with water or coffee or sprayed with a fire extinguisher. Three flights were diverted because of battery fires in that period.
Homeland Security Secretary John Kelly told a House of Representatives panel Wednesday that he is considering expanding the electronic-device ban to 71 additional international airports.
The devices aren’t allowed in cabins of flights originating in 10 airports, primarily in the Middle East. Kelly didn’t name the additional airports under consideration.
The restrictions stem from news reports that terrorists may be able to hide explosives in electronic devices but cannot detonate them remotely. The restrictions require passengers to store laptops and other electronics larger than a cellphone in their checked luggage in the cargo compartment.
During his testimony before the House Committee on Homeland Security, Kelly said he was aware of the fire danger involving the batteries and hoped foreign airports would increase their screening techniques to avoid the need to expand the electronics ban.
“There’s a lot of talk out there that lithium batteries are dangerous in and of themselves, that they just burst into flames,” he said. “So we are also dealing with that as well.”
10 Things to Look for When Buying a Notebook
In 1995, the laptop is ugly. Not only ugly, but also heavy and expensive. Several thousand dollars bought a small 4:3 screen, keyboard and hard disk, chunky, megabytes, not bytes. Thankfully, the modern laptop is a totally different beast. They are lighter, faster, more flexible and cheaper than ever before. And there’s a whole lot: in the first 2010 quarter, about 50 million tablets were sold worldwide.
The vast options in today’s laptop market makes finding the right system a bit of a challenge. There are desktop replacement laptops, ultralights, high-end systems for gamers and cheap netbooks for taking notes. You have to know exactly what you’re looking for.
Here’s how you get started: Read through the next 10 pages to figure out what you should keep an eye out for in a new laptop. If you know why each of the next 10 features is important, you’ll be prepared to pick the perfect notebook for your needs.
Buying consumer electronics is always a battle against irrelevancy. It’s tough to buy something that will be outdated in just a few months, but there’s always new gear just beyond the horizon — you can’t put off a purchase forever. To maximize the value of a laptop purchase, buy shortly after a product refresh. New systems usually come out shortly after Intel launches new processors. Look up review for laptops. See a model that was highly rated but came out nine months ago? A newer version will probably be along within a few months. Don’t buy a laptop months into its release cycle unless you’re shopping on a budget and spy a killer deal.
Picking a warranty isn’t an easy decision, either. If you’re clumsy and accident prone (or paranoid), opting for a long warranty will put your mind at ease. But it will also cost you an extra hundred dollars or more, depending on the kind of coverage you choose. Total coverage packages for accidents are expensive, but you’ll be glad you have it if you accidentally step on your screen and break the LCD. And there’s nothing wrong with going for the cheapest limited warranty you can — just don’t drop your new laptop!
We keep mountains of personal information on our computers. There’s always a risk when storing information digitally and on the Internet, but laptops elevate that risk by being much easier to steal than desktop machines. Some laptops, specifically those aimed at business and enterprise users, are built with these concerns in mind. For example, fingerprint scanners are found on plenty of business PCs and require users to pass a scan before logging into the operating system.
Many laptops also include Kensington security slots. Security cables are attached to these slots to bolt a laptop to a table or kiosk. Ever look at laptops at a store like Best Buy? Then you’ve probably seen one of these in action. Durability is another factor when it comes to security: To ensure no data loss happens due to a butterfingers moment, Panasonic sells ToughBook laptops designed to survive a nasty drop onto unforgiving concrete.
Laptop security features can help protect you, but never assume they’ll keep your data safe from determined crooks. Being careful with your laptop is the best way to protect it. And that brings us to our final tip: choosing a warranty and judging laptop release cycles to know when to buy.
3.Ports and Expandability
Every computer user is familiar with the USB port, but not everyone is aware that a much faster update to the standard, USB 3.0, is slowly spreading through the computer industry. USB 3.0 can be 10 times faster than its predecessor in real-world usage, delivering transfer speeds of up to 400 megabytes per second [source: EverythingUSB]. Even if you don’t own any USB 3.0 hardware right now, consider future proofing when buying a new laptop. You might be really thankful you have that USB 3.0 port down the road.
There are other ports to consider as well. Do you want HDMI to output video to a TV? Do you need an SD card slot for downloading digital camera photos to your laptop? Will you need an Ethernet port for Internet or will a laptop’s built-in WiFi connection be enough?
If you plan on keeping a laptop for several years, learn how customizable or expandable it is. For example, Apple’s laptops are known for their build quality — and for being locked down and difficult to perform maintenance on. The Apple a1322 batteries are integrated, rather than removable. Many PCs have removable batteries that can easily be swapped out or replaced.
Google your laptop to see if owners have found it easy to add additional RAM or swap out the hard drive. Either of those upgrades could give your laptop an extended lease on life sometime down the road, but some casings are much easier to open up than others. On a similar note, some laptops are especially designed to keep your data more secure. That’s our next topic.
4.Do you need an optical drive?
Optical storage mediums have been key computer components since the first CD drives arrived on the scene, but cheap flash storage in the form of USB drives and cloud storage on the Internet have nearly eradicated their necessity. When was the last time you used a CD burner? Do you watch DVDs on your computer, or do you stream movies from Netflix? If you do either of those things regularly, or need to be able to burn DVDs or CDs for work, that’s okay — there are still plenty of laptops outfitted with CD/DVD combo drives. Blu-ray drives are even optional in a small selection of laptops, most commonly the media-focused 15-inch (38-centimeter) and 17-inch (43-centimeter) models.
If you’re on the fence about needing a disc drive, educate yourself on cloud storage. Dropbox makes it easy to transfer files between multiple computers. Netflix makes it easy to stream movies and TV shows from the cloud. Spotify, Rdio, iTunes Match and a host of other music services allow you to stream music to your computer as long as you have an Internet connection. And there’s always the option of using an external hard drive or flash drive to transfer files from a computer that does have a disc drive.
That brings us to another important consideration: making sure your laptop has all the ports you need.
5.Storage and Memory
For years, all laptops stored data on spinning physical discs called hard drives. Most of them still do, but faster solid state drives that use silicon-based memory are becoming more affordable and more prevalent in mobile computers. Because solid state drives don’t rely on moving parts, they’re more reliable in computers that tend to get bumped and jostled around. The downside: They’re expensive and don’t offer nearly as much data storage.
Storage space may not be a big concern for you — if you store most of your data in the cloud and don’t plan to load a computer up with gigabytes of music and video, a SSD or small HDD will suit you just fine. Random access memory (RAM) is a different story. Every piece of software running on a computer and the operating system itself (usually meaning Windows) stores data in RAM to function. The more RAM you have, the better — it’s smart to upgrade this component when possible. To run Windows 7, 4 gigabytes is a comfortable minimum.
Apple’s MacBook Air and similar computers in the Ultrabook category of PCs are beginning to offer SSDs at reasonable prices. If you need more than 128GB of storage, best stick to a traditional hard drive, or be prepared to pay a pretty penny for an upgrade. Speedy SSD storage is fantastic, but in many cases going with a thin-and-light computer means giving up a disc drive and embracing the Internet cloud.
6.Processor and Graphics
A computer’s processor determines how efficiently it can run programs, multi-task and basically do everything we expect of modern computers. Processors get faster and more efficient every year. Most Windows-based computers run on Intel’s processors; smaller ultraportables, such as Apple’s thin MacBook Air, run on ultra low voltage processors that draw less power than some of Apple’s other chips. Quad-core chips deliver more powerful performance, but even dual-core processors are up to the task of playing 1080p video and running system-intensive programs like Photoshop.
The graphics processor, or GPU, is important when it comes to playing HD video and running games. Many laptops use integrated graphics rather than dedicated graphics chips. These are less powerful (and also less battery intensive), but powerful enough to decode 1080p video. Dedicated graphics chips are important for playing video games, but for the average computer user, the two components on the next page — hard drive storage memory — are more important.
7.Screen Size and Resolution
There are three common screen sizes in the notebook industry: 13 inches (33 centimeters), 15 inches (38 centimeters) and 17 inches (43 centimeters). The smallest in this group of laptops obviously prioritize portability, and often forgo DVD drives to make their bodies thinner and lighter. The mid-size category has a bit more range: Some heavier systems operate as desktop replacements, while others are light enough to still be easily portable while offering large screens. The largest category of laptops are, well, pretty huge. They always offer high resolution displays and powerful hardware, but can easily weigh up to 10 pounds (4.5 kilograms).
Generally, 15-inch (38-centimeter) and especially 17-inch (43-centimeter) laptops are large enough to be decent TV/computer monitor substitutes for watching video, especially on the go. Smaller notebooks, measuring 11 to 14 inches (27.9 to 35.6 centimeters) may be a bit small for watching movies, depending on your personal taste. More importantly, their displays are often lower resolution. The resolution is the total number of pixels contained in the display — more pixels allow for more content to be displayed on screen at once.
Resolutions typically range from 1366 by 768 — just a bit larger than 720p — to 1920 by 1080, aka 1080p. Laptop makers will often use lower resolution displays to cut costs. On the next page, we’ll get into the processor and graphics card, two other critical components. But if you’re comparing two computers, go for the higher resolution screen when possible, or choose an HD upgrade option if it’s available.
8.Size and Weight
Heavy laptops kill mobility. In 2011, computer processor maker Intel began pushing an ultrabook category that focuses on lightweight systems — usually weighing about 3 pounds (1.3 kilograms) — to make use of its ultra low voltage CPUs. Ultrabooks do away with disc drives and focus on portability, long battery life and a starting price range of $800 to $1000. These laptops aren’t powerful enough for some users, and do away with a disc drive others find important, but they demonstrate a trend towards lightweight notebooks that are extremely portable.
Pounds add up quickly. Most 15-inch (38-centimeter) laptops often weigh around 5 pounds (2.3 kilograms), which is a manageable weight to carry between home and the office every day. But some laptops creep up into the 7 to 8 pound (3.2 to 3.6 kilogram) range, and laptops that heavy can easily be relegated to at-home machines due to their weight.
There are a couple ways to get around the weight issue. You can always shop for a brand like Sony’s Vaio, which makes weight a priority concern. The downside: Vaios are more expensive than other notebooks with similar performance. Second option: Go for a computer with a smaller screen.
9.Battery Life
Laptop computing is all about mobility, and battery life is perhaps the most crucial consideration when picking a laptop that’s going to be used regularly on the go. If you’re in the market for a desktop replacement system — meaning you’ll mostly just leave it on your desk and don’t plan on regularly taking it on trips — battery life isn’t quite as critical. Otherwise, pay close attention to how long a laptop’s battery will last.
As laptops get slimmer and designers pay more attention to making them sleek and compact, more and more systems use integrated non-removable batteries. The trade off for that sleeker laptop body is that it’s impossible to buy a backup battery and swap the two out to double battery life. Finally, always be skeptical of claimed battery life times. The numbers that laptop makers convey often refer to light usage with a dimmed screen. Assume you’ll get 1 to 2 hours less than claimed while browsing the Web and running multiple applications — and possibly even less if you’re playing games or doing something else that taxes the computer.
The size and power of a laptop affects how much room there is in the body for a Dell d620 laptop battery (and how quickly it’s drained). Next up: finding that size and weight sweet spot.
10.Analyze Your Usage Scenario
We’re not all looking for the same qualities in a laptop, and the kind of programs you want to run determine your demands in the categories that follow. First, consider why you’re buying a laptop. Is it to make PowerPoint presentations, take notes and do other simple business tasks? Or do you plan on watching HD movies, playing video games and video chatting with your friends?
Figure out how much you can afford to spend on a laptop and find the best system in that price range with the features you need. Our first example above, for business use, would be a pretty cheap laptop — you can easily spend less than $1000 on a model that will run Microsoft Office and other productivity software. Another factor to consider: Do you want a Mac or a PC?
While Apple’s laptops are pricier than many PCs, there are only a few Apple notebook models to choose from. Apple’s extremely light MacBook Air models start at $1000 and are fast, capable machines, but lack disc drives unlike the larger, more powerful MacBook Pros. The least expensive 13-inch MacBook Pro starts at $1200, while the 15-inch jumps up to a pricey $1800.
If you’re looking for a PC, there’s a whole lot of hardware to be familiar with before you pick out a winning system. First up: battery life.