June 2006 – Battery Education

Batteries That Overheat Stop Working

I had an interesting conversation with a customer this morning and the customer’s scenario went like this: A customer with a 4G iPod states that his iPod overheats and his battery is completely drained when attached to his computer's USB’s port. In addition his backlight does not work unless connected to AC power.

We discussed software settings: iPod has backlighting, so you can see the display in low light. This will help save your battery power so your battery will last longer. You can configure the iPod so the backlight turns on for a set amount of time when you press a button or move the scroll wheel. See your manual for specific instructions, but in short you can have backlight always on or have it off after a period of time between 2 and 20 seconds.

There is also a condition with iPod’s called the “Black Screen of Death” (iPod users have named this condition not I) where an iPod's screen gets dark after a few minutes of operation and the back of the iPod gets hot hot. It is a condition where the iPod itself is defective.

But what to me is interesting is that the iPod was only getting hot when connected to a USB port. It reminds of the worst possible condition of lithium ion or lithium polymer.

The worst condition is keeping a fully charged battery at elevated temperatures, which is the case when running a battery powered device on AC power for extended periods of time. If used on main power, the battery inside a device will only last for 12-18 months. Also the battery will not all of sudden stop working but over time gradually lose the capacity to power your device little by little.

This raises the question then; should a battery pack be removed when the device is running on main AC power? Considering the fact that a fully charged battery operates at an internal temperature of 113°F and then keeping a battery in the device and keeping it fully charged will create a constant state of elevated internal temperature and ultimately cause a decline in battery capacity over time.

Removing the battery in a device then will protect the internal circuitry from maintaining a high internal temperature. It is interesting how Apple warns against the iPod battery from being operated at high temperatures over 95°F. It seems then that a prolonged USB connection to an iPod will indeed cause a battery to decline gradually since the battery can be charged via a USB connection. Obviously the longer the prolonged connection then the faster the battery capacity decline!

But since removing an iPod battery is not the easiest thing to do use the USB connection in temporary states and you will avoid most overheating issues with your iPod battery and help prolong its life.

Until next time Dan Hagopian www.batteryship.com
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What Causes Batteries to Fail?

Why do batteries fail? Can there be such a thing as a bad battery? How do I know if my battery is bad? The most effective means of understanding the status of a battery is to test the battery using a battery analyzer. However as this may not be readily available for you let’s examine some of the possibilities that could cause a battery to “fail” and also understand some things you can do to help isolate if a battery is indeed bad.

First of all batteries with different cell chemistries or constructions may fail in different ways. For example:

• Batteries can have faulty cell design
• Batteries can be manufactured under uncontrolled processes
• Batteries can be operated in uncontrolled conditions
• Batteries can be abused
• Batteries can degrade and lose power

Battery Cell Design Faults – include weak mechanical design, inadequate pressure seals and vents, the specification of poor quality materials and improperly specified tolerances can be responsible for many potential failures.

Uncontrolled Manufacturing Processes include – badly run production facilities which lead to cell short circuits, leaks, unreliable connections, sealing quality, mechanical weakness, and contamination. An example of a manufacturing process out of control is variable coating thicknesses of the active chemicals on the electrodes would affect cell capacity, impedance and self discharge.

Uncontrolled Operating Conditions – perfectly good batteries fail when you use operate them in conditions where they shouldn’t be like: using the battery in a device that it was not specifically designed for, charging the battery with an incorrect adapter/charger, extreme environmental conditions (most handheld consumer batteries operate best when ambient temperatures are between 32°F-95°F), and physical damage.

Abuse – Abuse means deliberate physical abuse by the end user as well as accidental abuse which may be unavoidable. This may include dropping, crushing, penetrating, impacts, immersion in fluids, freezing or contact with fire.

Battery Degradation and Power Loss – A battery over time degrades and eventually stops working, this is no surprise, but why this occurs is really a fascinating yet technical process. These reasons are complex issues that are way beyond user control and are wholly contained within your battery and within your device! These reasons for battery degradation and power loss over time is due to declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge. For a more detailed analysis of battery degradation and power loss please visits this special report on Battery Degradation and Power Loss.

My iPod Displays an Exclamation Point and Folder Icon?

The battery charge may be low. If you just received a new battery then you will need to charge it for at least 3 hours. Charge the battery via an adapter and wall outlet for best results (charging via a usb/firewire cable can pose many other issues). Also the iPod may display a lighting bolt icon or charging animation which means that your iPod is receiving a charge. FYI: iPod's battery works best at room temperature. (between 32° to 95° F). A low battery icon will appear if you have left your iPod iPod in the cold or in the sun on a very hot day. Never leave your iPod in a vehicle's interior when parked in the sun. Do not expose your iPod to direct sunlight for extended periods of time. Do not take your iPod into a sauna or steamroom and never submerge your iPod in water.

If the Exclamation Point and Folder Icon appears and it is not a battery charging issue then it could mean that your iPod is “locked up”. A lockd iPod (frozen iPod or won't turn on iPod) may be caused by the iPod being paused or the Hold switch is in the locked position. If so, a lock symbol may appear on the screen. Slide the Hold switch to the unlocked position and check the screen. After that reset your iPod. Even if the Hold switch is already in the unlocked position, I would toggle it so it's locked and back again to eliminate problems that are easy to fix.

Some iPod models require a specific or later version of iPod software and if these iPods do not have this required software then the exclamation point and or folder icon may appear. This can happen if the iPod was partitioned or reformatted using an incompatible format. To fix the problem restore the iPod using the iPod Updater application. If the iPod Updater doesn't recognize the iPod, try forcing the iPod into disk mode and then try the restore process again.