Portable External Laptop Batteries for Computers
Universal Replacement Battery Pack for HP, Toshiba, Compaq etc
Jan 6, 2009
Notebook batteries are specific to each model. Even different models from the same brand can't share batteries. As batteries for old laptops become more scarce, users will have to start looking for alternative solutions to power their PCs.
One solution is to use an external battery to supply low voltage power to the laptop.
How External Batteries Work
External batteries plug into the notebook's DC input socket, just like the notebook's own power supply. The notebook thinks it is getting power from its normal DC power supply unit (connected to the mains AC power), not realizing that it is actually a battery.
Since the notebook doesn't know it is running on a battery, its power saving mode will not be triggered. To enable power saving, the notebook's settings for AC or mains external supply should be modified.
One external battery can be used to power many different models of notebooks, even those from different manufacturers, as long as the voltages are matched. To support different models of computers, the output voltage and the plug can be changed.
The external battery is recharged by plugging into the mains AC wall socket.
As a bonus, most external batteries will have a 5 volt USB socket to charge cellphones and MP3 players.
AC Output
Some external battery packs can output 110 or 230 volts AC mains power.
This reduces compatibility problems, but increases weight (the notebook's AC power supply needs to be carried) and reduces available battery capacity. This is because power is lost during the conversion of DC to AC, then AC back to DC.
How to Use an External Battery
External batteries can be used to replace the internal battery: by removing the dead internal battery and plugging in the external battery. The internal battery is removed so that energy is not wasted charging a dead battery.
An external battery can also be used with a working internal battery, to extend the running time of the notebook. After the external battery is discharged, it is disconnected and the internal battery takes over.
How to Choose an External Battery
The DC voltage and the electrical plug (sometimes called "tips") need to match (see photograph below).
If a computer is not on the list of compatible models, details of the voltage and electrical connector need to be checked. Even if some models of a brand are supported, it doesn't mean that other models of the same brand will match.
The computer and the external battery should be tested together in the shop before purchase. Some external batteries do not output the exact voltage required, having only two fixed output voltages.
For example, an external battery may output 14 volts and 20 volts. It is switched to 14 volts to power a 16 volt notebook. This may or may not work, which is why testing is required.
For best results the external battery should be able to output different voltages in steps of one volt. Unfortunately not all external batteries are capable of this.
External Battery Limitations
External batteries use the same lithium-ion technology as internal batteries. They will have similar
- cost
- capacity (a few hours, maybe only 1 or 2 depending on battery capacity and notebook size; manufacturers' battery-life estimates are often optimistic)
- recharge time (a few hours)
- lifespan (a few years)
External batteries are useful but are not the answer to all problems. Computer users will still have to
- deal with weight issues
- save power by reducing screen brightness
Using small low-power netbooks (small notebooks with 9 or 10 inch screens) is one way to maximize available battery power.
