How Long will My iPod Video Play?

Is it true the ipod video (fifth gen ipod) will hold a charge for up to 20 hours? Let's see!

First of all the legal fine print on Apple's iPod page explicitly refers to the 60 Gb iPod Video only being able to play (hold a charge in the battery) up to 20 hours. I would bet with all of its legal woes on the horizon this claim from Apple that the "new iPod boasts up to 20 hours of battery life, five hours more than before" is legally valid in a controlled test environment.

But consumers don't live in a controlled test environment, which is why I would not be surprised if your new ipod video (fifth gen ipod) will NOT hold a charge for 20 hours.

The legal keyword here is "up to". So even if the battery lasts an hour Apple is legally covered!

On the new 5th Generation iPod battery performance has to now be measured with: music playback, photo playback, and video playback (on iPod screen or through a TV).

Apple claims that the new 30GB iPod will play music for 14 hours, photo and music slideshows for 3 hours, and iPod on-screen video for 2 hours. In a iLounge test they found that the new iPod Video played music for 15 hours and 30 minutes, photo slideshows for 2 hours and 32 minutes, on-iPod video for 2 hours and 10 minutes, and iPod-to-TV video for 3 hours and 10 minutes.

Apple also claims that the new 60GB iPod will play music for 20 hours, photo and music slideshows for 4 hours, and video for 3 hours. Again in In a iLounge test they found that the new iPod Video played music for 19 hours, 50 minutes, but exceeded Apple’s photo and video claims, playing a music photo slideshow for 4 hours, 47 minutes, iPod-screen video for 3 hours, 23 minutes, and on-TV video for a hefty 5 hours and 24 minutes.

But everyone may experience slightly different battery life play times. For example here is a situation from a user quoted from the Apple fourms:

"It is clear that when you use the click wheel a lot, you assume that your battery life gets smaller quickly. I had a problem with my ipod 5G 30Gb battery life : Firstly, I charged it (as soon as i received it) until the plug icon appeared on the screen (1h 30mn) . Then I listened music 'til it was fully discharged. The battery life was approximately 8hrs. Then, this battery life decreased to 5hrs last day. I called Applecare ; the guy told me to restore my ipod, then to let it discharge fully, and to refill it for 4 hrs even if the plug icon appear on the ipod screen. After that, I synchronized ipod to itunes and let it play allnight long to see the battery life now. It played music with default settings during 15hrs 'til it shut down. These are the Apple specifications for that ipod. My problem wasn't the battery, but the battery life calibration, which has not been done as it should."

The reality is all batteries including batteries designed specifically for iPods (regardless of generation) have a certain amount of capacity and once the full amount of the capacity has been used then your battery will stop working. This is the normal function of battery designs.

In fact consider this taken from Apple iPod Warranty Care: "Your one year warranty includes replacement coverage for a defective battery. You can extend your coverage to two years with AppleCare Protection Plan. During the second year, Apple will replace the battery if it drops below 50% of its original capacity. If it is out of warranty, Apple offers a battery replacement for $59, plus $6.95 shipping. Apple disposes your battery in an environmentally-friendly manner." So basically Apple is correctly telling you that your battery will die with time and use. No questions about that; and that Apple is telling you that your battery replacement plan will cost you a total of $59, plus $6.95 shipping. Folks: Before you pay that amount go to BatteryShip.com and replace your battery for far less!

The admittance by Apple that your ipod battery will dies is based on real limitations of the battery's internal design.

Before I discuss the limitations of the battery's internal design there are external limitations that reduce the playtime of your iPod Video – personal usage. Yes running your iPod Video, even under normal usage, will reduce your iPod Video's playtime. Personal usage has way too many variables to describe here but in short – the way you use your iPod will determine, in part, how long your iPod battery will last.

Now on to the techincal internal battery design limitations…

Battery Capacity

The more the better (and more expensive), however there are a number technical limiations that force the iPod Video battery to cap off at where it is at.

A key requirement to know is the necessary battery capacity and runtime. This will define the overall physical size of the battery. Apple chose to ignore this rule and due to its desire to make the iPod as small as possible forced battery manufacturers to comply to the physical space limitations first instead of the runtime specifications. It traded capacity for space.

Capacity and runtime is measured in Amperes. Amps – or A – is an abbreviation of Ampere, a 19th century French scientist who was a pioneer in electricity research. Amps measure the volume of electrons passing through a wire in a one second. The electrical current is measured in amperes, where 1 ampere is the flow of 62,000,000,000,000,000,000 electrons per second!

Amp hours – or Ah – measures capacity. Amp hours is what is ultimately important to consumers as it is the capacity or amp hours that tells us how long we can expect a battery to deliver a charge before it runs out. As with all metric measurements, Amps can be divided into smaller (or larger) units by adding a prefix, in this case by adding an "m" to the amp hour we are renaming the amp hour to milli amp hour: mAh; (1Ah = 1000 mAh).

In addition when we consider the design capacity we must determine the chemical needed to insure that the necessary runtime will be met. Lithium is used because of its electrochemical properties. Lithium is part of the alkali family of metals a group of highly reactive metals. Li reacts steadily with water. In addition the per unit volume of lithium packs the greatest energy density and weight available for this grouping of reactive metals.

iPod batteries that have a chemistry design of either lithium ion or lithium polymer will over time regardless of usage will experience power loss to the point of non-functioning. In fact contained within your ipod battery is a design and chemistry make-up that impacts your battery life far more than your usage activity and there is no amount of conditioning you can do to prevent the ultimate power loss of your ipod battery.

Here is another situation from a user quoted from the Apple fourms:

"Recently, my iPod battery didnt seem to be lasting anywheres near 18 hours, so I tested it, and after about 4 hours the meter was still 3/4 of the way full, so i did the math and figure it was fine. My question is though, is it normal for the iPod to loose quite a bit of battery power without turning it on, because i lost about 1/8 of the life without using it for the past two days."

The reason why this occured is due to elevated self-discharge as we will see below but let's first continue on our discusson.

We know that batteries are rated by their voltage, their mAh, and of course the chemicals contained within. These three technical facts about your battery give some insight into the actual life of (energy stored within) your battery. But the length of time an ipod battery can operate is not linear to the amount of energy stored in the battery.

In fact their are four ongoing problems with your ipod battery that affects performance and the extended battery life of your ipod. They are: declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge.

These are more complex issues that are beyond user control and are wholly contained within your ipod battery and within your ipod itself! As we will see these issues (declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge) do more to cause iPod Battery Degradation and iPod Power Loss than your typical iPod owner could ever do.

Declining Capacity

Declining capacity is when the amount of charge a battery can hold gradually decreases due to usage, aging, and with some chemistry, lack of maintenance. iPod batteries are specified to deliver about 100 percent capacity when new but after usage and aging and lack of conditioning a iPod battery's capacity will drop. This is normal. If you are using an ipod battery (or any lithium-ion or lithium-polymer battery) when your battery's capacity reaches 60% to 70% the iPod battery will need to be replaced. Standard industry practice will warranty a battery above 80%. Below 80% typically means you have used the practical life of a battery. Thus the threshold by which a battery can be returned under warranty is typically 80%.

Loss of Charge Acceptance

The loss of charge acceptance of the Li ion/polymer batteries is due to cell oxidation. Cell oxidation is when the cells of the battery lose their electrons. This is a normal process of the battery charge creation process. In fact every time you use your ipod battery a loss of charge acceptance occurs (the charge loss allows your battery to power your ipod). Capacity loss is permanent. Li ion/polymer batteries cannot be restored with cycling or any other external means. The capacity loss is permanent because the metals used in the cells run for a specific time only and are being consumed during their service life.

Internal Resistance

Internal resistance, known as impedance, determines the performance and runtime of a battery. It is a measure of opposition to a sinusoidal electric current. A high internal resistance curtails the flow of energy from the battery to a iPod device. The aging of the battery cells contributes, primarily, to the increase in resistance, not usage. Expect a typical life span of a Li ion/polymer battery to be one to three years, whether it is used or not. The internal resistance of the Li ion batteries cannot be improved with cycling (recharging). Cell oxidation, which causes high resistance, is non-reversible and is the ultimate cause of battery failure (energy may still be present in the battery, but it can no longer be delivered due to poor conductivity).

Elevated Self-Discharge

All batteries have an inherent self-discharge. The self-discharge on nickel-based batteries is 10 to 15 percent of its capacity in the first 24 hours after charge, followed by 10 to 15 percent every month thereafter. Li ion battery's self-discharges about five percent in the first 24 hours and one to two percent thereafter. At higher temperatures, the self-discharge on all battery chemistries increases. The self-discharge of a battery increases with age and usage. Once a battery exhibits high self-discharge, little can be done to reverse the effect.

Premature Voltage Cut-Off

Some iPods do not fully utilize the low-end voltage spectrum of an ipod battery. The ipod device itself cuts off before the designated end-of-discharge voltage is reached and battery power remains unused. For example, a ipod that is powered with a single-cell Li ion battery and is designed to cut-off at 3.7V may actually cut-off at 3.3V. Obviously the full potential of the battery and the device is lost (not utilized). Why? It could be something with elevated internal resistance and iPod operations at warm ambient temperatures. iPods that load the battery with current bursts are more receptive to premature voltage cut-off than analog equipment. High cut-off voltage is mostly equipment related, not battery.

So to sum up will your iPod Video play up to 20 hours – yes. Will it play for 20 hours straight – more than likely – no. So what do you do – accept it or don't buy the iPod.

Until next time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.

Technical Reasons Why iPod Batteries Die

iPod batteries that have a chemistry design of either lithium ion or lithium polymer will over time regardless of usage will experience power loss to the point of non-functioning. In fact contained within your ipod battery is a design and chemistry make-up that impacts your battery life far more than your usage activity and there is no amount of conditioning you can do to prevent the ultimate power loss of your ipod battery.

We know that batteries are rated by their voltage, their mAh, and of course the chemicals contained within. These three technical facts about your battery give some insight into the actual life of (energy stored within) your battery. But the length of time an ipod battery can operate is not linear to the amount of energy stored in the battery.

In fact their are four ongoing problems with your ipod battery that affects performance and the extended battery life of your ipod. They are: declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge.

These are more complex issues that are beyond user control and are wholly contained within your ipod battery and within your ipod itself! As we will see these issues (declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge) do more to cause iPod Battery Degradation and iPod Power Loss than your typical iPod owner could ever do.

Declining Capacity

Declining capacity is when the amount of charge a battery can hold gradually decreases due to usage, aging, and with some chemistry, lack of maintenance. iPod batteries are specified to deliver about 100 percent capacity when new but after usage and aging and lack of conditioning a iPod battery's capacity will drop. This is normal. If you are using an ipod battery (or any lithium-ion or lithium-polymer battery) when your battery's capacity reaches 60% to 70% the iPod battery will need to be replaced.

Standard industry practice will warranty a battery above 80%. Below 80% typically means you have used the practical life of a battery. Thus the threshold by which a battery can be returned under warranty is typically 80%.

Loss of Charge Acceptance

The loss of charge acceptance of the Li ion/polymer batteries is due to cell oxidation. Cell oxidation is when the cells of the battery lose their electrons. This is a normal process of the battery charge creation process. In fact every time you use your ipod battery a loss of charge acceptance occurs (the charge loss allows your battery to power your ipod). Capacity loss is permanent. Li ion/polymer batteries cannot be restored with cycling or any other external means. The capacity loss is permanent because the metals used in the cells run for a specific time only and are being consumed during their service life.

Internal Resistance

Internal resistance, known as impedance, determines the performance and runtime of a battery. It is a measure of opposition to a sinusoidal electric current. A high internal resistance curtails the flow of energy from the battery to a iPod device. The aging of the battery cells contributes, primarily, to the increase in resistance, not usage. Expect a typical life span of a Li ion/polymer battery to be one to three years, whether it is used or not. The internal resistance of the Li ion batteries cannot be improved with cycling (recharging). Cell oxidation, which causes high resistance, is non-reversible and is the ultimate cause of battery failure (energy may still be present in the battery, but it can no longer be delivered due to poor conductivity).

Elevated Self-Discharge

All batteries have an inherent self-discharge. The self-discharge on nickel-based batteries is 10 to 15 percent of its capacity in the first 24 hours after charge, followed by 10 to 15 percent every month thereafter. Li ion battery's self-discharges about five percent in the first 24 hours and one to two percent thereafter. At higher temperatures, the self-discharge on all battery chemistries increases. The self-discharge of a battery increases with age and usage. Once a battery exhibits high self-discharge, little can be done to reverse the effect.

Premature Voltage Cut-Off

Some iPods do not fully utilize the low-end voltage spectrum of an ipod battery. The ipod device itself cuts off before the designated end-of-discharge voltage is reached and battery power remains unused. For example, a ipod that is powered with a single-cell Li ion battery and is designed to cut-off at 3.7V may actually cut-off at 3.3V. Obviously the full potential of the battery and the device is lost (not utilized). Why? It could be something with elevated internal resistance and or iPod operations at warm ambient temperatures. iPods that load the battery with current bursts are more receptive to premature voltage cut-off than analog equipment. High cut-off voltage is mostly equipment related, not battery.

Until next time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.

iPod Battery Technical Facts

Apple has shipped over 12 million iPods since their debut in October 2001. 12 million ipod users are now faced with an inevitable requirement which is: what do you do when your iPod battery dies?

Let's begin with the basics…

1. The ipod battery can be replaced by you. Go to www.Batteryship.com for detailed instructions. An ipod battery replacement can be done in just a few easy steps. iPod batteries begin at $9.99 for a 3rd gen and a mini. 4th gens, photos, video and the super capacity first gen are just a few dollars more.

2. iPod batteries last a long time, but like all batteries the longevity of a battery life depends on usage patterns. iPod batteries are made up of a lithium ion and or lithium polymer chemical compound. Etiher has a half life, a recharge cyle of between 300-500 charges. So depending on your particular usage pattern you could be using an ipod battery that is 3 years old or 18 months old.

3. iPod batteries like all batteries are rated by electrical specifications that include its volt and milliAmp hour rating. The most common voltage you will see for an iPod battery is 3.7 V. Volts as you may know is the electrical measure of energy potential. You can think of it as the pressure being exerted by all the electrons of an iPod battery's negative terminal as they try to move to the positive terminal.

Amps or A is an abbreviation of Ampere, a 19th century French scientist who was a pioneer in electricity research. Amps measure the volume of electrons passing through a wire in a one second. One Amp equals 6.25 x 1018 electrons per second.

Amp hours or Ah measures capacity. That is ultimately what we want to know about the ipod battery. Amp hours quantify how long a battery can deliver a certain amount of charge before it runs out. As with all metric measurements, Amps can be divided into smaller (or larger) units by adding a prefix. In the case of ipod batteries, a milliAmp hour (mAh) is most commonly used. Note that 1000 mAh is the same a 1 Ah. (Just as 1000mm equals 1 meter.) Note that Amp hours do not dictate the flow of electrons at any given moment. PDA batteries with a 1 Amp hour rating could deliver ½ Amp of current for 2 hours, or they could provide 2 Amps of current for ½ hour. The higher the mAh on the iPod battery the longer it will last and of course the more you will pay.

4. iPod Battery Meter. If you spend anytime in the Apple forums you will come across a common complaint that goes something like: ‘I charged my iPod for more than four hours and then when I turn it on, the battery meter says it only has about 25% (or less) charge. So I plugged it back in to charge overnight and it still says very little charge.’

The good news is is that your iPod is probably fine, fully charged, and ready to play for many uninterrupted hours. How is this possible when the ipod battery meter reads as if there is no battery charge whatsoever? Because the battery meter only approximates when you should recharge your ipod battery!

Some ipod battery meters will read empty but after about 20 minutes of use fills in the black bars to read more like the real capacity of the battery.

Since the meter is an approximation to indicate a need to recharge why then is my ipod powering down? If your battery is truly dead then buy another one and replace it yourself. If your battery is not dead then recalibrate the ipod battery meter. To re-calibrate, run the iPod until it shuts down. Recharge fully, using the AC power (mains) adapter, not a USB or Firewire port. Do not recharge until the iPod shuts down due to low battery again. This does not mean you have to leave it running for hours; use it normally, but hold off on any "top-off" recharges.

If recalibrating does not solve your problem, try resetting your iPod (method varies by model) and/or restoring it (be sure you have all of your music on your computer before doing this). Then repeat the full cycle of discharge and recharge.

5. With all that said your ipod battery will naturally degrade over time. How? Does it strictly have to do with my usage pattern? No not entirely. Contained within your ipod battery is a design and chemistry make-up that impacts your battery life far more than your usage activity and there is no amount of conditioning you can do to prevent the ultimate power loss of your pda battery.

For example we know that batteries are rated by their voltage, their mAh, and of course the chemicals contained within. These three technical facts about your battery give some insight into the actual life of (energy stored within) your battery.

But the length of time a pda battery can operate is not linear to the amount of energy stored in the battery. In fact their are four ongoing problems with all batteries that affect performance and the extended battery life of your ipod. They are: declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge.

These are more complex issues that are beyond user control and are wholly contained within your ipod battery and within your device! As we will see these issues (declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge) do more to cause an ipod battery Degradation and ipod power loss than your typical ipod owner could ever do.

Declining Capacity

Declining capacity is when the amount of charge a battery can hold gradually decreases due to usage, aging, and with some chemistry, lack of maintenance. iPod batteries are specified to deliver about 100 percent capacity when new but after usage and aging and lack of conditioning an ipod battery's capacity will drop. This is normal. If you are using an ipod battery (or any lithium-ion or lithium-polymer battery) when your battery's capacity reaches 60% to 70% the ipod battery will need to be replaced. Standard industry practice will warranty a battery above 80%. Below 80% typically means you have used the practical life of your ipod battery. Thus the threshold by which a battery can be returned under warranty is typically 80%.

Loss of Charge Acceptance

The loss of charge acceptance of the Li‑ion/polymer batteries is due to cell oxidation. Cell oxidation is when the cells of the battery lose their electrons. This is a normal process of the battery charge creation process. In fact every time you use your ipod battery a loss of charge acceptance occurs (the charge loss allows your battery to power your pda). Capacity loss is permanent. Li‑ion/polymer batteries cannot be restored with cycling or any other external means. The capacity loss is permanent because the metals used in the cells run for a specific time only and are being consumed during their service life.

Internal Resistance

Internal resistance, known as impedance, determines the performance and runtime of an ipod battery. It is a measure of opposition to a sinusoidal electric current. A high internal resistance curtails the flow of energy from the battery to an ipod device. The aging of the battery cells contributes, primarily, to the increase in resistance, not usage. Expect a typical life span of a Li‑ion battery to be one to three years, whether it is used or not. The internal resistance of the Li‑ion batteries cannot be improved with cycling (recharging). Cell oxidation, which causes high resistance, is non-reversible and is the ultimate cause of battery failure (energy may still be present in the battery, but it can no longer be delivered due to poor conductivity).

Elevated Self-Discharge

All batteries have an inherent self-discharge. The self-discharge on nickel-based batteries is 10 to 15 percent of its capacity in the first 24 hours after charge, followed by 10 to 15 percent every month thereafter. Li‑ion battery's self-discharges about five percent in the first 24 hours and one to two percent thereafter. At higher temperatures, the self-discharge on all battery chemistries increases. The self-discharge of a battery increases with age and usage. Once a battery exhibits high self-discharge, little can be done to reverse the effect.

Premature Voltage Cut-Off

Some ipods do not fully utilize the low-end voltage spectrum of an ipod battery. The ipod device itself cuts off before the designated end-of-discharge voltage is reached and battery power remains unused. For example, an ipod that is powered with a single-cell Li‑ion battery and is designed to cut-off at 3.7V may actually cut-off at 3.3V. Obviously the full potential of the battery and the device is lost (not utilized). Why? It could be something with elevated internal resistance and or using ipods at warm ambient temperatures. iPods that load the battery with current bursts are more receptive to premature voltage cut-off than analog equipment. High cut-off voltage is mostly equipment related, not battery.

Until next time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.

Battery Chemistry

Since the year 1800 when the first voltaic battery was invented portable battery power has been a fascination by many. In 1991 Sony commercialized the first lithium-ion battery and in 1999 lithium-polymer came out commercially with PDAs.

But what are the differences of the two chemistries and in terms of your PDA battery which one is better? In a nutshell the two chemistry types are similar but one benefit that lithium-polymer offers is that enables slim geometry that allows it to fit in small places like a PDA.

Let's look inside the battery technology a bit more!

Lithium-ion Battery:

    * The lightest of all metals
    * The greatest electrochemical potential
    * The largest energy density for weight.
    * The load characteristics are reasonably good in terms of discharge.
    * The high cell voltage of 3.6 volts allows battery pack designs with only one cell versus three.
    * It is is a low maintenance battery.
    * No memory and no scheduled cycling is required to prolong the battery's life.
    * Lithium-ion cells cause little harm when disposed.
    * It is fragile and requires a protection circuit to maintain safe operation.
    * Cell temperature is monitored to prevent temperature extremes.
    * Ccapacity deterioration is noticeable after one year (whether the battery is in use or not).

Lithium Polymer Battery:

    * The lithium-polymer differentiates itself from the conventional battery in the type of electrolyte used (a plastic-like film that does not conduct electricity but allows ion exchange – electrically charged atoms or groups of atoms).
    * The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.
    * The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry.
    * Cell thickness measures as little as one millimeter (0.039 inches).
    * Can be formed and shaped in any way imagined.
    * Commercial lithium-polymer batteries are hybrid cells that contain gelled electrolyte to enhane conductivity.
    * Gelled electrolyte added to the lithium-ion-polymer replaces the porous separator. The gelled electrolyte is simply added to enhance ion conductivity.
    * Capacity is slightly less than that of the standard lithium-ion battery.
    * Lithium-ion-polymer finds its market niche in wafer-thin geometries, such as PDA batteries.
    * Improved safety – more resistant to overcharge; less chance for electrolyte leakage.

Until next time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.

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! As we will see these issues (declining capacity, increasing internal resistance, elevated self-discharge, and premature voltage cut-off on discharge) do more to cause Battery Degradation and Power Loss than your typical portable device owner could ever do.

Declining Capacity

Declining capacity is when the amount of charge a battery can hold gradually decreases due to usage, aging, and with some chemistry, lack of maintenance. PDA batteries, for example, are specified to deliver about 100 percent capacity when new but after usage and aging and lack of conditioning a pda battery's capacity will drop. This is normal. If you are using a pda battery (or any lithium-ion or lithium-polymer battery) when your battery's capacity reaches 60% to 70% the pda battery will need to be replaced. Standard industry practice will warranty a battery above 80%. Below 80% typically means you have used the practical life of a battery. Thus the threshold by which a battery can be returned under warranty is typically 80%.

Loss of Charge Acceptance

The loss of charge acceptance of the Li‑ion/polymer batteries is due to cell oxidation. Cell oxidation is when the cells of the battery lose their electrons. This is a normal process of the battery charge creation process. In fact every time you use your battery a loss of charge acceptance occurs (the charge loss allows your battery to power your device by delivering electrical current to your device). Capacity loss is permanent. Li‑ion/polymer batteries cannot be restored with cycling or any other external means. The capacity loss is permanent because the metals used in the cells run for a specific time only and are being consumed during their service life.

Internal Resistance

Internal resistance, known as impedance, determines the performance and runtime of a battery. It is a measure of opposition to a sinusoidal electric current. A high internal resistance curtails the flow of energy from the battery to a device. The aging of the battery cells contributes, primarily, to the increase in resistance, not usage. The internal resistance of the Li‑ion batteries cannot be improved with cycling (recharging). Cell oxidation, which causes high resistance, is non-reversible and is the ultimate cause of battery failure (energy may still be present in the battery, but it can no longer be delivered due to poor conductivity).

Elevated Self-Discharge

All batteries have an inherent self-discharge. The self-discharge on nickel-based batteries is 10 to 15 percent of its capacity in the first 24 hours after charge, followed by 10 to 15 percent every month thereafter. Li‑ion battery's self-discharges about five percent in the first 24 hours and one to two percent thereafter in the following months of use. At higher temperatures, the self-discharge on all battery chemistries increases. The self-discharge of a battery increases with age and usage. Once a battery exhibits high self-discharge, little can be done to reverse the effect.

Premature Voltage Cut-Off

Some devices like pdas do not fully utilize the low-end voltage spectrum of a battery. The pda device itself, for example cuts off before the designated end-of-discharge voltage is reached and battery power remains unused. For example, a pda that is powered with a single-cell Li‑ion battery and is designed to cut-off at 3.7V may actually cut-off at 3.3V. Obviously the full potential of the battery and the device is lost (not utilized). Why? It could be something with elevated internal resistance and or pda operations at warm ambient temperatures. PDAs that load the battery with current bursts are more receptive to premature voltage cut-off than analog equipment. High cut-off voltage is mostly equipment related, not battery.

Until next time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.

Energy Potential of Lithium

PDA batteries widely employ either a Lithium-ion or a Lithium-polymer chemical composition and so it leads us to question why? Why is lithium ever-present in PDA Batteries today?

We know that since millions of people own PDAs (for every purpose imaginable) it is understandable that a rechargable power cell be available. In fact if it wasn't for lithium I would find it rather astonishing that PDA's would be so widely used today. Lithium makes recharging your PDA battery cost-effective. So what exactly is lithium?

General Characteristics of Lithium

    * Name: lithium
    * Symbol: Li
    * Atomic number: 3
    * Atomic weight: [ 6.941 (2)] g m r
    * CAS Registry ID: 7439-93-2
    * Group number: 1
    * Group name: Alkali metal
    * Period number: 2
    * Block: s-block
    * Standard state: solid at 298 K
    * color: silvery white/grey
    * Classification: Metallic

Lithium is used, amongst many other uses, as a battery anode material (due to its high electrochemical potential) and lithium compounds are used in dry cells and storage batteries. In fact the energy of some lithium-based cells can be five times greater than an equivalent-sized lead-acid cell and three times greater than alkaline batteries. Lithium cells often have a starting voltage of 3.0 V. This means that batteries can be lighter in weight, have lower per-use costs, and have higher and more stable voltage profiles.

For a scientific review of Lithium visit http://www.webelements.com/webelements/elements/text/Li/index.html

Until next time – Dan Hagopian, Batteryship.com
Copyright © BatteryEducation.com. All rights reserved.

Amps and Volts: Battery Basics?

This is a back to basic articles on understanding a batteries electrical ratings. Let's take a real question from a real person:

"I have a sony clie PEG-NR70V/U PDA. The battery that you show that would fit my unit is 1200 mah and 3.7 volts. On the back of my PDA it says 800 mAh and the volts is 5.2. Is the battery that you show for my unit the same?"

This is a great question and is actually quite common and so it is wise that we gain a better understanding of what the ratings mean.

All PDA batteries have an electrical specifications that include its volt and milliAmp hour rating. These terms are abbreviated as we see in the following example: 3.7 V, 1600 mAh.

Volts – or V – are an electrical measure of energy potential. You can think of it as the pressure being exerted by all the electrons of a PDA Batteries negative terminal as they try to move to the positive terminal.

Amps – or A – is an abbreviation of Ampere, a 19th century French scientist who was a pioneer in electricity research. Amps measure the volume of electrons passing through a wire in a one second. One Amp equals 6.25 x 1018 electrons per second.

Amp hours – or Ah – measures capacity. That is what is ultimately important to consumers as it is the capacity or amp hours that tells us how long we can expect a battery to deliver a charge before it runs out. As with all metric measurements, Amps can be divided into smaller (or larger) units by adding a prefix, in this case by adding an "m" to the amp hour we are renaming the amp hour to milli amp hour: mAh.

In the case of PDA Batteries, a milliAmp hour (mAh) is most commonly used notation system. Note that 1000 mAh is the same a 1 Ah. (Just as 1000mm equals 1 meter.) Note that Amp hours do not dictate the flow of electrons at any given moment, that is the role of volts. PDA batteries with a 1 Amp hour rating could deliver ½ Amp of current for 2 hours, or they could provide 2 Amps of current for ½ hour.

Typically, PDA Batteries will use 1 to 3 Amps per hour, depending on the model's processor speed, screen size, screen brightness adjustment, usage, and other factors.

Some of our batteries will have higher amp-hour ratings than the original battery found in your device and will not cause any incompatibilities. It is actually good because you are getting greater capacity.

Volts on the other hand have to be within a nominal range (reasonable range) of each other. Manufacturers rate a voltage cell, which then becomes the nominal voltage, historically with a 3.6V while others picked 3.7V to name the cell. The functionality and performance of either cell is identical and cannot be differentiated by the device. The explanation above applies to a single Li-Ion cell in series. When a battery has two or more Li-Ion cells in series, the voltage is multiplied by the number of cells in series.

Now back to the question we began with…..

"I have a sony clie PEG-NR70V/U PDA. The battery that you show that would fit my unit is 1200 mah and 3.7 volts. On the back of my PDA it says 800 mAh and the volts is 5.2. Is the battery that you show for my unit the same?"

To understand the answer to the question let's look at a math formula for the complete formula of Watts….

Watts = Volts x Amps x k(one unit length of wire)

Since the length of your PDA's wire inside the battery casing is difficult to know (unless you open the casing) let's just use a more common formula for Watts: (NOTE: DO NOT OPEN YOUR BATTERY'S CASING, EXTREME HARM WILL COME TO YOU)

Watts = Volts x Amps

Now the orignial Clie battery came with 800 mAh and the volts is 5.2. So the Watts would be:

41.6= 5.2 x 8

The Clie battery on our page is 3.7 V and 1200 mAh. So the Watts would be:

44.4= 3.7 x 12

Remember that I'm 1200 mAh is the same as 12 Ah and 800 mAh is the same as 8 Ah

So as we discussed early a nominal range is inherent in voltage ratings and slight variations in voltage generally do not impact the performance of your PDA. We see this all the time with universal and external batteries. The original battery might be specified at 10.8 Volts, but customers using a universal part can operate their laptop safely at either the 10 or 11 Volt setting.

There is plenty more info you can get in this blog as well as online.

Until next time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.

What is a Watt?

Here are some definitions of watts on the Web:

  • A measure of the amount of work done by a certain amount or amperage of electric current at a certain pressure or voltage.
  • A watt is a measurement of total electrical power. Volts x amps = watts.
  • A measure of power or the rate of energy consumption by an electrical device when it is in operation, calculated by multiplying the voltage at which an appliance operates by the current it draws (Watts = Volts X Amperes).
  • Watts is the measurement of the amount of electrical power drawn by the load.
  • A measure of electricity.
  • The power required to maintain one ampere of current at a pressure of one volt when the two components are in phase with each other.

Until next time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.

Watts are Volts x Amps?

Watts, Volts and Amperes are basic units of measure for a DC (Direct current) power supply. A battery, for example, is a direct current power supply and the combined measure Volts x Amps = Watts.

Watts are important because watts represent the electrical energy spent by a battery (power generator) and used by an electrical device. Watts in effect is the measure of the amount of work done by a certain amperage (amount) of electric current at a certain pressure or voltage.

Voltage is the amount of "pressure" of electrons as the electrons pass from a negative connector to a positive connector.

Amperes (commonly "Amps" ) is a measurement of quantity of the number of electrons passing through a given wire per second.

How many electrons are in an Ampere?

A lot: 62,000,000,000,000,000,000 electrons per second!

Until next time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.

What is the Difference Between Lithium Ion and Lithium Polymer?

Lithium ion:

  • The lightest of all metals
  • The greatest electrochemical potential
  • The largest energy density for weight.
  • The load characteristics are reasonably good in terms of discharge.
  • The high cell voltage of 3.6 volts allows battery pack designs with only one cell versus three.
  • It is is a low maintenance battery.
  • No memory and no scheduled cycling is required to prolong the battery's life.
  • Lithium-ion cells cause little harm when disposed.
    It is fragile and requires a protection circuit to maintain safe operation.
  • Cell temperature is monitored to prevent temperature extremes.
  • Capacity deterioration is noticeable after one year (whether the battery is in use or not).

Lithium Polymer:

  • Lithium polymer chemistry differentiates itself from Lithium Ion in the type of electrolyte used (a plastic-like film that does not conduct electricity but allows ion exchange – electrically charged atoms or groups of atoms).
  • The polymer electrolyte replaces the traditional porous separator, which is soaked with electrolyte.
  • The dry polymer design offers simplifications with respect to fabrication, ruggedness, safety and thin-profile geometry.
  • Cell thickness measures as little as one millimeter (0.039 inches).
  • Can be formed and shaped in any way imagined.
  • Commercial lithium polymer batteries are hybrid cells that contain gelled electrolyte to enhane conductivity.
  • Gelled electrolyte added to the lithium ion polymer replaces the porous separator. The gelled electrolyte is simply added to enhance ion conductivity.
  • Capacity is slightly less than that of the standard lithium ion battery.
    Lithium ion polymer finds its market niche in wafer-thin geometries, such as PDA batteries.
  • Improved safety – more resistant to overcharge; less chance for electrolyte leakage.

Until Next Time – Dan Hagopian, BatteryShip.com
Copyright © BatteryEducation.com. All rights reserved.