Laptop Auto Power Adapter Buying Guide
The most comprehensive buying guide you can find on Internet
What is a Laptop Auto Adapter?
A Laptop Auto Adapter is a type of power supply – typically one that is used in the car to power the laptop. Other names include Laptop Car Charger, Auto Power Adapter, Auto Air Power Adapter, Auto Notebook Power Adapter, or Auto DC Adapter.
The Laptop Auto Adapter operates by plugging into the cigarette lighter socket in the car. It is able to convert the 12V voltage (sometimes is 24V in some heavy duty trucks or military vehicles) of the automobile electrical system, into the required input voltage of the laptop. By connecting the output plug of the adapter to the laptop, users can then power the machine in the car. Most of the Laptop Auto Adapters are capable to run the laptop and charge the laptop battery simultaneously.
A Laptop Auto Adapter looks very similar to an AC power adapter. They are usually rectangular in shape and black in color, and consist of an input and an output cable. The major difference between the two is the AC power adapter is usually equipped with a power cord as the input cable, where as the Laptop Auto Adapter utilizes the cigarette lighter plug to draw current from the vehicle’s battery.
Below is a typical setup of a Laptop Auto Adapter at work:
Who needs a Laptop Auto Adapter?
Anybody who tends to operate a laptop in the car for a long period of time needs a Laptop Auto Adapter. The following are some examples of the people / organizations that can use the Laptop Auto Adapter to enhance their mobile computing experience:
• Law Enforcement
• Fire Services
• Emergency Medical Services
• Public Transportation System
• Public Utility Services
• Waste Management
• Commercial Service and Delivery
• Warehouse Management
• Military and Intelligence
• Traveling Professionals
The Laptop Auto Adapter Buying Guide
Unlike the AC Power Adapter, the Laptop Auto Adapter usually doesn’t come in the original laptop package. People who want to use the Laptop Auto Adapter need to purchase the adapter separately. Most of the Laptop manufacturers offer the Laptop Auto Adapter option. Buying from them guarantees the full compatibility between the laptop and the adapter. However, it is also often the more expensive way to obtain the adapter. We sometimes see the price of the Laptop Auto Adapter option from the laptop manufacturer being 2X compared to the alternative solutions.
If you know what to look for, finding a cheap alternative Laptop Auto Adapter solution with similar performance is easy – this is the reason why we constructed this Laptop Auto Adapter Buying Guide. In this document, you are going to learn the important parameters to consider when searching for your alternative laptop car charger.
Input Voltage Range
Most passenger vehicles and trucks are designed to output a 12V voltage at the cigarette lighter socket / utility power outlet. However, the voltage on the outlet is not always regulated perfectly at the 12V. In some situations, such as during the car’s engine cold-start process, the output voltage may vary. It can sometimes go as low as 10V or as high as 18V. Having a Laptop Auto Adapter fail to work in the full range voltage swing of your vehicle utility outlet can post issues.
The minimum accepted input voltage range for a Laptop Auto Adapter is from 11V to 16V. An adapter with this specification is usually cheap in price. But, the owner might run into the potential issue that the adapter sometimes stops functioning. The better input voltage range specification is from 10V to 24V. With the wider range design, the auto adapter can always guarantee continuous operation.
There are situations when users need to have a Laptop Auto Adapter working in an even wider range. For example, military vehicles or some foreign made heavy duty trucks are equipped with the 24V battery system and have the chance to output a voltage as high as 32V at the cigarette lighter socket. In this case, an adapter capable of working in 10V to 32V input voltage range is required. Additionally, some warehouse management services are performed by using the mobile data terminal installed on a forklift of which the utility outlet can generate a voltage as high as 60V. A voltage step-down device is needed to be installed between the forklift battery and the auto adapter.
The Laptop Auto Adapter needs to have a fuse built-in on the input to protect itself because of the unstable utility outlet output. In the automobile engine ramp up or slow down process, there might be an extra current surge flow into the auto adapter. Without the proper fuse installed, the surge current might damage the auto adapter, and sometimes the laptop.
Some vendors put the fuse on the adapter main body. It is usually the more expensive way to implement the fuse, but offers an easier way to have the fuse replaced. Others put the fuse inside the cigarette lighter plug – cheaper in cost but harder for the fuse replacement. When you buy the auto adapter, you should check if the package comes equipped with some spare fuses for future use. Believe us, there is high possibility that you will need to replace the fuse sometime in the future.
Output Power Level
Now-a-days, the mainstream laptops usually ask for no more than 70W input power. The manufacturers have a tendency to carefully select the components they put onto the laptop motherboard, to control both the heat generation inside the laptop chassis and the cost to build the laptop. However, there are machines that demand more than 70W out there. Some gaming notebooks and mobile workstation solutions are more power-hungry to support the installed, high end graphic display card, or the fast multi-tasking CPU. The best way to determine what power level you need is by looking at the label on your laptop AC power adapter. If you have a 90W AC power adapter for your notebook, try to get a 90W auto adapter. As long as you can match the power level, the auto adapter should be able to support the energy needed to run your laptop on the road.
The output voltage specification you need to look for on a Laptop Auto Adapter depends on the input voltage requirement of your laptop. Most of the laptop manufacturers have now settled on two voltage systems: 12V and 19V. Some still use odd voltages, such as 15V. The best place to look for the right needed output voltage is on your AC power adapter.
It is also recommended that the output voltage of the Laptop Auto Adapter to be as clean as possible. However, adapter vendors usually won’t make the voltage regulation and noise specification available to the public. (Read this link for the definition and measurement of the voltage regulation and noise on the adapter output.)
Output Plug Dimension
One of the complaints regarding the laptop design is that different vendors tend to implement different input DC Jacks on the laptop. In addition, the information of the DC jack dimension is usually not widely available to the public. By doing so, laptop vendors force the laptop owners to buy power accessories directly from them to insure the power adapters have the correct output plug which can match the DC jack on the laptop. The notebook vendors can thus earn high profits due to the high listed price on the power accessories.
Below you will find the commonly used power adapter output plug:
• Cylindrical shape 2-pin plug: this is the most common type of the output plug used on the Laptop power adapters. They have several different variations, such as:
o Outer plug dimension (OD): 5.5mm, Inner plug dimension (ID): 1.7mm
o OD: 5.5mm, ID: 2.1mm
o OD: 5.5mm, ID: 2.5mm
One thing to note is the center pin is sometimes designed with reversed polarity: sometimes the center pin represents power rail, sometimes it is the ground rail. The best place to check the desired center pin polarity is on the AC power adapter label. The first picture below shows the output plug is a center pin negative design. The second one is the center pin positive design.
• 4-pin snap and lock plug: Sometimes it is called power Mini-DIN connector. They can usually be identified by an engraved symbol on the back of the plug, consisting of two wide arrows pointing in opposite directions, but parallel to each other, or sometimes one wide arrow inside a box, pointing towards the end of the male connector.
• 3-pin plug to enable the data communication between the laptop and the adapter: the latest technology in laptop power accessories is to implement a data pin inside the adapter output plug. When the laptop registers that it has already used the full allowable power from the power adapter, it will try to limit the power usage in the system by shutting down or slowing down a system function. The 3-pin plug is easily identified by its larger cylindrical shape. There are also plug adapters to make the old 2-pin plug work on the new 3-pin plug system (and vice versa).
Again, the best place to find the output plug information is on your AC power adapter. We are in the process of establishing a database with accurate plug information for each laptop existing on the market. Please check back for more information later.
Auto / Air Adapter
Sometimes the vendors promote their products as the auto / air adapters. The add-in phrase, air, simply indicates that the adapter can be used to power the laptop on the airplane if the user can locate an empower connector to plug in the auto / air adapter. It is a common practice to embed an empower plug inside the cigarette lighter plug of the Laptop Auto Adapter. The front tip of the cigarette lighter plug is designed to be detachable so the empower plug can be shown. Please see the below picture for reference.
Do you need the air adapter feature? It depends. Not all the airline companies deploy empower connectors on the seats on the airplane. You should first check the information on seatguru.com, determine if the airline you usually take offers this feature, and then make your decision.
Misc. Features and Functions
There are other less important, but still viable features and functions to consider when purchasing the Laptop Auto Adapter. For example:
• How long does the input and the output cable need to be?
• Do you need the cable organizer built-in on the input and output cable to better organize the wires?
• Should the input cable and the output cable come from the same side of the adapter so that you can throw the adapter into one of the compartments of the vehicle’s front dashboard?
• Is the adapter shape small enough to carry around?
• Will you use a laptop vehicle mounting cradle in the car? Is there any compatibility issues when using the vehicle mount with the auto adapter?
• Do you need a mounting basket to mount the auto adapter somewhere in your car?
The Laptop Auto Adapter can really enhance your experience while performing mobile computing. It is not difficult to find a suitable Auto Adapter for your laptop. You can either buy the auto adapter option from the laptop manufacturer, or use the buying guide to find a cheaper alternative solution. Please feel free to use the contact us button to give us your comments and feedback. Together we can make this Laptop Auto Adapter Buying Guide better.