C21-X402 ersatz Laptop Akku fuer Asus X402 Series, X402C Series, 5136mah / 38wh, 7,4V

First of all, you need to assure the model of your laptop or the part number of your laptop battery. Then look for the battery you need at Laptop-Battery. Finally, you can check whether the battery you find is compatible with your laptop or not on the "Compatibility" table (for example, Lenovo ThinkPad P72). If you don't know how to find the right battery for your laptop, you can click "How to find one correct battery for my laptop?" for more details. Moreover, you can click the link "Contact Us" on the bottom of this page to ask us.

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Usually NO. New batteries come in a discharged condition and must be fully charged before use. It is recommended that you fully charge and discharge the new battery two to four times to allow it to reach its maximum rated capacity.
It is generally recommend an overnight charge (approximately twelve hours). It is normal for a battery to become warm to the touch during charging and discharging.
When charging the battery for the first time, the device may indicate that charging is complete after just 10 or 15 minutes. This is a normal with rechargeable batteries. New batteries are hard for the device to charge; they have never been fully charged and not ''broken in''. Sometimes the device's charger will stop charging a new battery before it is fully charged. If this happens, remove the battery from the device and then reinsert it. The charge cycle should begin again. This may happen several times during the first battery charge. Don't worry; it's perfectly normal.

All laptops are different, however, they usually share similarities when removing the main battery. That being said, all newer MacBooks from Apple use integrated batteries that require service to remove. Most smaller PC laptops, those with a screen size of 13 inches or less, like an Ultrabook, also have a built-in battery that is not accessible. If your laptop's battery is not accessible, help from a repair technician to change the battery is likely necessary.

If you are using a Windows or Linux based laptop, this page provides a general idea on how to remove the laptop battery. If you are replacing a laptop battery, you can insert the new battery after removing the old battery.

1. If your laptop is plugged in, either unplug it or disconnect the power cable.
2. Turn your laptop over so the bottom is facing up.
3. Locate the battery latch on the bottom of the laptop. The image above shows some common battery latches found on laptops.
4. To remove the battery, slide the latch switch to the opposite side and hold it open until the battery is released.
5. On some laptops, the battery pops out on its own. On others, you need to pull the battery out gently with the tips of your fingers.

Although most laptops only have one latch, there are some that require you to slide two latches to remove the battery. On these laptops, the latches still look similar to the examples above, but require you to move both at the same time, usually towards each other.

There are also some older laptops (IBM laptops) that require the latch to be pulled out and then pushed towards the battery.

If you cannot find any latches or buttons for releasing the battery, it is likely the laptop utilizes a different mechanism to release the battery. The laptop may need to be serviced by a licensed repair technician who can remove it through partial or full disassembly of the laptop.

We recommend referring to the laptop documentation or checking the manufacturer's website for steps on how to remove the battery. The documentation or website helps you determine if servicing is required to remove the battery.

When you get a new laptop or new laptop battery, proper charging, discharging, usage and storage will allow you to maximize your battery's life and capabilities. Before even powering up your laptop for the first time, it is important to know just how to charge and care for your battery in order to get the most out it for as long as you can.

1. Charge & Discharge
   According to CNET authors Asher Moses and Brian Nadel, the first thing you should do with your new laptop is ''let the battery completely drain(5%) before you recharge it''. Letting the battery completely drain(5%) by using it without AC power, and then recharging it to 100 percent before using it again, helps to establish memory within the battery regarding how much of a charge can be held. Do this for at least the first two times when using your laptop on battery power, and repeat as often as you can to get the most out of your battery.
2. Storage
   If you plan to use your laptop as a desktop most of the time, Rick Broida of "PC World" suggests you take the battery out of your laptop and use only AC power. Only put the battery in and charge it whenever you plan on moving the laptop and using it without AC power, because ''if you leave your laptop plugged in 24/7... the battery rarely (if ever) gets a chance to discharge, [so] it loses its capacity to hold a charge''. Charge the battery before moving your laptop, and discharge it completely before recharging again, if you can.
3. Temperature & Climate
   One of the main causes of battery failure is overheating. "PC Magazine's" Erik Rhey suggests that you can avoid overheating by using cooling pads and not placing your laptop on soft surfaces like pillows and blankets. Some batteries are actually designed to sense if they are getting too warm and simply will not charge if they are, so it is in your interest to keep your battery cool. Dust getting into the laptop and clogging the cooling fan can also cause overheating problems, so try to keep the area around your laptop clean. Of course, leaving your laptop in your car where it can become excessively hot can also cause problems, so avoid that as well.
4. Power Settings
   Once you have gotten the hang of charging your batteries, visit your computer's Power Settings in the Control Panel and dim your computer's display, adjust the timeout settings for your display to turn off and for your laptop to sleep, and see if any advanced settings can be changed to really extend your battery life as far as you can.