Typically, a power supply is selected depending on the required power of individual power lines. As you probably know, the main load falls on the 12V line, so exactly the power provided by this line is very important. Many users make mistake taking the maximum values of current provided by any individual power line and multiply them by the voltage to obtain the output power. That is wrong because the 3.3V and 5V as well as different 12V lines are dependent on one another and that’s why in the specifications for +3.3 V, 5V and +12 V is given their combined power.

To determine what power you need you have to calculate the consumption of your computer components. There are many online calculators, which you can use for this purpose, but you should know that there is no such situation in which all components are loaded to their maximum values. For example if you have two hard drives and one optical drive in the worst case you will have two active working devices. Also in 3D games and applications the mainly loaded device will be the video card, unlike the CPU which will be away from its maximum load. It is also possible the opposite situation, where the processor performs havy calculations, while the video card stays almost unused. Typically, the actual values are about 75-80% of those made by such calculators, but if you add additional capacity for future upgrades, the values calculated in such a way would be quite normal. For a modern computer, as a minimum can be considered values of approximately 350W.

The next thing that you should pay attention to, when purchasing a new power supply is the energy efficiency. The higher values mean that your power supply will convert the voltage from the electrical network more effectively and of course it will produce less heat and noise. Most widely used power supplies have an energy efficiency ratio of about 70-75% but higher-quality power supplies can be over 80% efficient.

Most power supplies are equipped with 80mm or 120mm cooling fans. Larger fans recommended because of the small amount of noise they produce compared with the 80mm fans. There are also the so-called “completely silent” models without fans. They have specially designed cooling system with high efficiency, but are usually considerably more expensive and their power is limited to about 300W – 500W.

Another important requirement for the power supply is to have a sufficient number of connectors, which can save you a lot of problems when adding new hardware. There are also Modular Power Supply Units in which the users can modify the power connectors to suit their personal needs. Unlike the conventional design where power cables are permanently connected to the power supply, a modular power supply provides an option allowing unused cables to be detached from it. By allowing cables to be detached, modular cabling can help you not only to reduce the clutter of unused cables but also improve the airflow within the case.

1. Battery Care.

Today all modern notebooks and netbooks are equipped with lithium-ion batteries. Along with their advantages over the other types of batteries, they have several characteristics that must be considered in order to preserve their nominal capacity for a longer period of time.

Lithium-ion batteries are sensitive to ambient temperature. They may not be used at temperatures below zero degrees, since this significantly reduces their capacity.

Although lithium-ion batteries do not suffer from the “memory effect”, they still must be regularly “trained”. It means that you should completely dissolve and then recharge your battery at least every 2-3 weeks. In some notebooks for that purpose there is special function, accessible in the BIOS,but this can be done manually, by stopping all energy saving features and allow the laptop to completely shut down by itself.

If you are planning during most of the time to use your notebook connected to the AC adapter (e.g. use it as a desktop replacement) it is recommended to remove the battery (for example – when it’s half charged) and put it in place with low temperature and away from direct sunlight. Of course, you should consider that in case of power supply interruption you will lose your data.

Contacts of the battery could be oxidized, and even the thinnest oxide layer may reduce the transfer of power from your battery to the notebook. Therefore it is recommended to clean the battery’s metal contacts every 2-3 months. Unfortunately I can’t give you an accurate advice about how it’s best to make such cleaning, but however, do not use sandpaper. Maybe it is best to do that with rubbing alcohol on a damp cloth.

2. How to minimize the energy consumption.

The time for autonomous work of the laptop depends not only on the capacity of its battery, but also on its consumption depending on several factors such as characteristics of the computer hardware and software, and the system settings.

You must pay more attention to the hardware when purchasing you computer. If the requirement for maximum operating time of battery is critically important, maybe you should look for device equipped with more energy efficient processor and a solid-state storage drive, which requires less power, since there are no spinning parts. Moreover, the large amount of memory also saves some operations of the operating system, which reduces the unnecessary energy consumption. Additional time to work can be gained by choosing the optimal operating system. Of course the choice of operating system also depends on the hardware capabilities of your computer. According to unofficial data, portable computers with Windows 7 running about 20-30 minutes longer with a single battery charge, compared to computers running Windows XP or Windows Vista. Anyway, it is recommended that the operating system is updated regularly. Another important thing is the regular defragmenting of hard drive that must be made at least every 2-3 months. Defragmenting allows your operating system to rearrange the file fragments so they are closer together on the hard drive, decreasing the time your system must spend searching for files. That’s why an optimization of your hard drive can provide you with additional battery power.

3. Extension of the battery operating time.

Above methods are important for maintaining the good condition of your battery, but there are ways allowing you to keep its capacity while operating with the computer. You can use those tips below to reduce the consumption of your laptop to a minimum. This will help you not only to achieve long operating time on battery, but will also reduce cases of rapid depletion of capacity, which could harm the battery.

When switching to battery power you have to ensure that the appropriate scheme for power management is chosen. Use the power management settings built in your operating system.

It is important to keep the temperature regime, so avoid extreme temperatures.  Laptop must be placed on a hard flat surface for better access of air to the cooling fan. Your laptop will operate more efficiently when it’s cooler so make sure to clean out your air vents regularly.

Turn off all peripheral devices that are not currently in use (e.g, Wi-Fi adapter or Bluetooth) and unplug external devices such as a USB mouse or an external drive.

Configure your display to turn off when not in use. It is also recommended to set the minimum adequate levels of display brightness and volume.

Use energy-saving features such as Hibernate or Standby. Hibernating a PC will actually save more power than when in standby mode because its state will be saved as it is, but the computer will shut down completely.

Avoid multitasking and close all the applications that run in the background on your computer. Shut down everything that isn’t crucial and use only what you realy need at any given time.

You should also avoid using the optical drive if possible. Optical drives consume larger amounts of energy compared with hard drives, so if you need data stored on a CD or DVD it’s recommended to copy it to your laptop’s hard drive before traveling.

Since usually a full stop of the propeller is not a sudden, there are some signs indicating that something is wrong. One of them is the increased noise emitted by computer sometimes. Usually that same sound is heard when you first start the system and then it stops by itself. After some time, however, that sound becomes a constant grinding noise, which indicates that the fan is permanently damaged, and its rotation is seriously hampered. Therefore, if any of these signs is present in your computer, do not hesitate to clean the power supply unit, because this may prolong its life and help you save money.

Important: With opening the computer’s case  you may lose your warranty, so be sure to check the documentation that comes from the company where it was purchased. If the warranty period has already expired, you can continue safely with the cleaning operation. Otherwise it may be better to take it to the workshop of the company where a specialist can take care of its cleaning. However, if you decide to perform the next operation, the only equipmemt you will need is a screwdriver, cleaning cloth, brush and can of compressed air.

OK. Let’s start.

The first and perhaps the most important thing to do before you start is to take care of your own safety,  so be sure to turn off the computer and unplug the power cord from the outlet.

1. Open the case and unplug all possible connectors that connect the power supply with the motherboard, CD / DVD-ROM devices, hard disks and floppy (if any exist).

2. Then remove four screws fixing the power supply unit to the rear panel of the computer. Keep in mind that the power unit is heavy and when you remove the last screw it could fall inside the computer and broke some of the components (for example, mothrboard or processor). Therefore it is better to hold the power unit with one hand while removing screws.

3. Once you remove the power block, it is time to proceed with its opening. For this purpose you have to remove several small screws (four in this case).

4. Once you get access to the electronic components of the power block, you must clean the accumulated dust, since it prevents them from better cooling. For this purpose you can use a synthetic bristle brush and compressed air spray.

Removal of the fan is pretty easy. All you need to do is to remove four screws, securing the fan to the metal case .

Now is the time to mention that according to its degree of wear, sometimes it’s better to replace it with new one, instead of cleaning it (especially if it makes loud or strange “buzzing” noises, which indicates permanent damage. If the wires are soldered to the curcuit board, your task becomes little more complicated, so it may take more time. The important here is the proper connection of wires when soldering them back to the circuit board.

After completion of the cleaning you can reassemble the power unit and install it back in the computer, but do not forget to connect all of its connectors to the corresponding  devices.

To avoid  damages, caused by an electrostatic fields you will need to be careful and to follow few simple rules. Otherwise this may lead to data losses and unwanted expenses.One of the rules says that everytime you touch something inside your computer, you need to ground yourself, as there is a risk that the accumulated static electricity in your body to harm some of the delicate electronic components. So, in order to avoid electrical shocks turn off the computer, unplug the power cable and ground yourself by using grounding strap or touch a metal faucet pipe. Touching the computer’s case also helps. Do this every time before touching anything inside you computer.

Additional damages could be provoked by power breakdowns.The breakdowns could be very briefly (parts of the second) or for a longer period. Fortunately,almost every high-graded and a bit more expensive power supply today has a good short power breakdown protection so your computer won’t even restart if you’re using one. But in case it does restart, the only thing that might be affected would possibly be the operating system and your unsaved documents.A serious power surge could cause much worse damages to your system and peripheral, as there is a momentary (but often fatal) increasing of the current power, coming from the electrical network.

The power surges can be caused by various reasons like problems with the electrical supplying equipment.Surges may be seen more frequently in facilities with rapidly varying electrical loads, often caused by the switching on / off of electric motors, air conditioners, electrical power tools,arc welders, electrostatic copy machines or elevators. Very often, a power surges are caused by lightning stroke, close crossing high-voltage cables or static electricity. The  outdoor assembled cabling (such as local network cables between close buildings),as well as TV antennas mounted on the roofs and the Cable TV wiring are most vulnerable.In most of this cases you would suffer a serious hardware damages.

In order to provide a normal working conditions for your equipment and for you as well, you need to connect a special device, that protects the system from all kinds of electrical power disturbances. Those devises are called “Surge Protectors” and you can easily buy one from a various range of retailers across the world.In case you don’t want your work to be interrupted by a power breakdown, you could by an UPS device in addition.

Surge protectors are designed to prevent the negative consequences of power surges, saving your expensive equipment. Note that most of the surge protectors won’t survive a direct lightning strike, but they are just fine for the common everyday power disturbances.Surge protectors are placed between the device you want to protect and the wall plug or Ethernet socket. When you choose what to buy, first thing you should consider is their rapidity (Response time). Note that when a electric power surge is present,surge protectors don’t act immediately because of the slight delay caused by the way they work. In other words the longer the response time the longer the connected equipment will be exposed to the surge. The most used composite parts used for making the surge protectors are the Gas discharge tube (GDT) and metal-oxide varistors (MOV). They have response times measured in nanoseconds which in most cases it is enough to protect your system.

A standard metal-oxide varistor protector is made of a plate of metal oxide (typically granular zinc oxide), connected to both the grounded and the main supplying cables through a couple of semiconductor elements.If the voltage is low (below a predefined level) the semiconductor material reaches a very high resistance levels and the electrons flow along the supplying cable.In case the voltage gets higher, the semiconductor gets “unleashed”, which makes him very low resistant.Then some of the electrons are diverted through the grounded conductor and the sensitive electronic equipment is already  surge protected and safe.

The second type of surge protectors – Gas discharge tubes (GDT) are very similar to the metal-oxide varistors, talking about the way they operates.The difference is, that instead of the triple semiconductor-metal-oxide system they are using an inert gas.If the voltage is low (in the normal levels )  the electrons flow along the supplying cable and the connected devices work normally. In this case, we can say that the inert gas is a “weak” conductor, because the low voltage isn’t enough to ionize his electrons.However, when the voltage gets too high, the electrons flow ionizes the inert gas and it becomes a conductor, consequently it diverts the  unnecessary energy through the grounded end of the protector.

As we mentioned before, the thing these two methods have in common is their operating principles – the unwanted energy is being diverted away of the cirquit. But, there’s another  type of  surge protectors – instead of diverting the unwanted electrons flow, these devices are just slowing it down.

Uninterruptible Power Supply (UPS).

Generally, those type of devices contain a battery and a logical (electronic) block.When working in a normal mode( no power crashes) the battery is being charged by the standart electrical instalation, and it’s ready to supply you with energy in case of a power breakdown.The logical block role is to watch out for such crashes and when detects one to provide the computer system with power form the battery. There are few different types of Uninterruptable power suplies but the most used are -  Offline, Line – Interactive and Оnline UPS.

The offline UPS is the simpliest and the cheapest one. Its role is to watch for the incoming voltage and  to transfer it to the protected device if it is in normal rates.In case something goes wrong (power breakdown or overvoltage), then system switches the power consumption to the battery.

The Line-Interactive UPS is a little bit more expensive compared to the Offline UPS. But it is capable to compensate the insignificant power hesitations, without the need of switching to emergency mode.

The most expensive  and also most complicated UPS devices are the so called Online UPS. They have the ability to transform the incoming voltage, creating an extremely stable outgoing electric flow, which form and parameters doesn’t depend on the voltage coming from the electrical network.They are typically used in the hospitals for securing the life saving equipment.

In conclusion I want to note that a hundred percent effective surge protection still isn’t invented. Even the most expensive devices from the most famous companies cannot guarantee you a completely normal work during a power failure. Despite all, their use could significantly reduce the risk of data loss and destruction of expensive equipment.

However, if you want to take all the advantages of your batteries, there is some technical stuff you need to know about their tech specifications, the various types of batteries and the appropriate use and preservation methods. If you own a mobile computer, mp3 player, digital camera or any other battery supplied device then you should take a look of  the following advices.

According to some claims, if you are using a rechargeable battery and in some moment you decide to recharge it again before it is completely discharged (let’s say it is still half full) then sooner or later it’s capacity will be drastically reduced. Well, that sounds reasonable, but only if the battery is the older NiCd type. With the modern type of batteries like Li-Ion this charging method couldn’t harm the battery life, furthermore those newer batteries have greater power density and much better capacity than their NiCd analogs.

It is frequent occurrence, the battery life to be shortened due to constant and prolonged recharging, i.e. you should not leave your batteries connected to the recharger longer than  required.For example, let’s say  you have bought a brand new digital camera with brand new battery, that could ensure you taking 100 pictures using the flash.An year after inappropriate use (i.e. leaving the battery connected to the electrical charger after being completely charged) the life of this battery would be reduced to taking just 80 pictures for a charging cycle. The same battery could probably take 90 pictures (ten more) if used more carefully. Of course this is just an hypothetical example.Note that no matter how carefully you use your batteries, they could hardly last more than five years. During this period you could take their full advantages for maybe 2 or 3 years, depending on the frequency of use and recharging.

Power supply in notebooks.

As you may have noticed, a laptop needs far more energy, compared to some other smaller devices such  as cameras and smartphones. In the same time, the laptop battery could not be too big or heavy, because in that case this would reflect negatively on the main advantages of the laptop, that are their small size and mobility.

The batteries used in the mobile computers could vary, depending on their sizes and models.Their capacity is measured using the measurement unit Ampere-hour (Ah) or milliampere – hour (mAh), but when you are choosing your laptop this shouldn’t be the only criteria for judging. The different models of mobile computers are requiring different voltage (7.2 V, 10.8 V, 14.4 V or 18 V). As you can see the voltage value is always divisible by 3.6. The most important thing  you should consider talking about the battery, is the cumulative amount of energy the battery could supply for a single charging cycle, measured in Watt-hours (Wh). In order to calculate that amount of energy you need to multiply the ampere-hour rating by the operating voltage.

Let’s say a middle class  laptop battery have 4.4 Ah (4400 mAh)  capacity and 10.8V voltage, i.e. 47.5 Wh active energy,while a battery with 4 Ah working capacity and electrical potential of 14.8 V, would give you a capacity of 59 Wh! Or in other words – despite that the first battery have greater ampere-hour rating than the second one, in the final analysis the second one provides about 30 % more  active energy, which is additional time you could use to work with your laptop, within a single recharging cycle. The batteries in ultra light mobile computers usually provide about 20 Wh of energy, while in the heavy weight category mobile computers this number often is more than 80 Wh.

So, if you want to avoid pointless money-drains and problems, first thing you need to do is to make sure your model have the  standard 6 cell battery, instead of the less effective 4 cell variant.Commonly, the retailers  are offering the ultra light laptops with an option for buying the light 4 cell version of the battery. Of course there are also special 8 or 9 cell batteries, which could provide far more energy without recharging, but respectively they are much more expensive and larger.

One more thing – some models have an additional extra battery slot. Most commonly this is the CD/DVD ROM slot, and the additional battery capacity is smaller than the main one’s, which is normal.The tricky part is that you could have your main battery untouched, unless you discharge the additional one completely ( i.e. if you have to take a long flight).This could give you the advantage of having a brand new main battery after an year of using, of course with having your second battery capacity partially wasted.

Longer battery life tips.

If you are planing to buy a rechargeable batteries, you should have the proper recharging device for them, because the higher the capacity of the battery- the higher the power requirements for the recharger. Otherwise – you will need much more time for charging. Moreover, the NiMH batteries are more  overheating and overcharging sensible and that’s why it is very important for your charger to be specially designed for NiMH batteries.So, remember-using older NiCd designed charger could seriously harm your NiMH batteries! The latest  charger models, optimized for NiMH and Li-Io batteries have built-in voltage and temperature sensors.So they can actually “feel” if the battery is fully charged and stop sending electrical impulses to it.

The so called fast chargers are giving you the opportunity to have your batteries charged in just about 20 minutes,but they also have their own advantages and disadvantages. It’s good to know that when using the fast charging mode and the charger indicator marks that the charging is over, you actually have your battery about 80% charged and you’ll need to wait at least an hour more if you want a fully charged battery. It’s also good to know that those fast charging chargers are causing a bit of “stress” to your batteries,but actually it’s much more important to have your battery charged when you need it most, than having to follow some strict charging schedule.That’s my opinion, anyway. After you finish recharging your batteries,if you don’t need them, it’s not a problem to leave them aside. It’s preferably to keep them in a room temperature away from direct sunlight. The batteries won’t discharge themselves during the next few months.