Li-Polymer Battery Facts

The Lithium-Polymer battery is a variation of the Lithium-Ion battery, which is why it's also called the Li-Ion Polymer battery. The difference is the Lithium-Polymer has a gelled electrolyte instead of a dry electrolyte and separator. This allows for the slimmer battery (smaller form factor) in demand for cell phones, which is why this battery was developed.

It doesn't have more capacity than a similarly-sized standard Li-Ion battery (it has actually a bit less). It just fits better into small portable devices.

One advantage of the Li-Ion and Li-Polymer battery is it can accept partial charges without degrading the battery or developing "memory." Because these batteries are sized very small to fit into very small devices, this is no small advantage. It's a crucial one (see the tips and a caution at the end of this article).

People want devices that have sound, color, fast processors, and other power-hungry features or components. They also want this device to fit into a pocket. To accommodate these requirements, something has to "give." And that is invariably the battery.

If you want whiz bang features and small size, you can't have super-long battery life. Period. We're up against the laws of physics. But you can have sufficient battery life. For example, properly charge an iTravl battery and the unit can run all day.

Facts about battery size vs. performance:

• The amount of energy a battery can store is a function of the physical size of certain battery components and thus of the battery itself. As you go up in battery capacity, you also go up in size and weight.

• Battery life is a function of how much energy a battery stores and the rate at which that energy is used. As you add power usage, you must also add size or reduce battery life.

Essentially, you are storing a charge in the physical materials of the battery. To store more charge, you need more material. And that material adds both size and weight. But nobody wants to carry a brick around. Do you?

The iTravl battery is a Lithium Polymer. We have had a few complaints that the battery doesn't seem to hold a charge. But we have evaluated several iTravl batteries and also compared them against the batteries in other devices and find the batteries hold a charge just fine.

If you own an iTravl or other device that uses an Li-Ion (or Li-Polymer variation) battery, you've made a good product decision. You just have to remember that engineering involves making choices and compromises to get the desired result.  If you follow the tips provided here, you should rarely--if ever--find yourself with a dead device. Do not charge the device "until the charging light goes out." The circuitry required to accurately determine battery condition would not fit into the case of any pocket device. In fact, not even 1/4 of the required circuitry would fit into any pocket device. The key is the amount of time under charge while using the recommended AC Adapter that comes with the device.

A note on iTravl battery life. We have tested these units extensively and found they have consistently long run times. One test consists of leaving the device to play the 3 hour, 8 second Paris Versailles audio book with screen set to  80% and Power Off set to Never, then coming back after six hours and finding the iTravl still hasn't drained the battery. You will read battery complaints on the various forums, but we guarantee you those folks failed to properly charge the battery. It's a 900mAH battery with a 300mAH charger. Battery charging isn't linear, so it's not 3 x 300mAH to charge it up. It takes about 6 hours.