Fully charged (green led on) but battery indicator not showing 100% OR poor battery life because indicated 100% is not fully charged.
This can happen after flashing a new ROM especially if you flash with charger or USB charging connected.
Always flash with no charger or USB connected (but make sure your battery is over 30% first).
Clear the battery stats as follows:- Power off the phone and fully charge it until the led is green.
- Turn the phone on for a couple of minutes until the battery indicator drops from 100% to 99%.
- Power off the phone again and charge it again while watching. As soon as the led turns green proceed to the next step.
- Unplug the charger, boot the phone into Recovery mode and reset (or wipe) the battery stats (on advanced menu in ClockWorkMod).
- Reboot and continue to use as normal.
Lithium-Ion Battery Do’s and Don’ts (thanks to RM Education)
Here is a quick list of Do’s and Don’ts for the care of your Li-Ion batteries.
Do’s
- Charge the battery as often as you can – avoid letting it run ‘flat’
Always charge the battery whenever possible. Frequent top-ups are much kinder to the battery than running it until it is flat. - Always ensure the battery is recharged as soon as possible after it becomes fully discharged. A battery will be permanently damaged if left for an extended length of time in a fully discharged state.
- When you receive a new phone, leave the battery to fully charge overnight.
- Calibrate a new battery by using it until it is fully discharged, and then re-charge it fully. Doing this once every month or two will help to keep the battery accurately calibrated.
- Remove the battery from the phone if it is going to be off for more than a month and store the fully charged battery in a cool place.
- Heat is the worst enemy of a battery. When charging, allow plenty of air to circulate around the phone, so that the battery is kept as cool as possible and also when in use.
- Remember that the battery half-life is rated for a certain total number of charge/discharge cycles (see your User Manual or Quick Start Guide for the rating, normally 300-500 cycles). For example, a battery that is rated for 3 hours and 500 charge/discharge cycles, will still be considered as within specification, even if it only lasts for 1 hour 45 minutes after 500 charge/discharge cycles.
- A Lithium-Ion battery will slowly deteriorate; a new battery will always perform better than one that is 6-months old.
Don’ts
- Do not expose the battery to excessive heat or cold (ie outside the range of 10-35 degrees Centigrade ambient).
- Do not allow a battery to be unused for more than a month or so. The battery will slowly discharge until it becomes fully discharged and this will permanently damage the battery cells.
- Do not charge your phone inside a carry case – the battery may get very warm.
- Do not deliberately use your phone until the battery is flat before recharging – frequent charges are far less stressful than deep charge/discharge cycles.
Remember: Your battery is slowly degrading all the time, even if it is not used. Keeping your battery as cool as possible will slow down this degradation considerably.
Important information: Some Quick Start Guides state the battery will ‘store more charge and have an increased life span if it is always allowed to fully discharge before it is recharged’. This information is applicable to Nickel-Cadmium and NiMH batteries, however Lithium-Ion batteries should be topped up as often as possible and you should avoid allowing them to become almost fully discharged if at all possible
Essential Li-Ion Information
Lithium-Ion batteries have a finite life, they slowly degrade from the day they are first made. The life of the battery will depend upon how you charge and discharge the battery and, in particular, the temperature at which the battery is kept. A manufacturer will rate a battery to the point where it holds 50% of its original capacity. At this point you should consider replacing the battery.
Lithium-Ion batteries are rated by the manufacturer for 300-500 full charge/discharge cycles, after which they may only charge to 50% or less. If you continually top-up the charge it will last much longer than if you always fully discharge the battery before re-charging it.
How can I prolong the life of my Lithium-Ion batteries?
Lithium-Ion batteries are very different from Nickel-Cadmium (Ni-Cd) batteries and must be treated differently. Lithium-Ion batteries are rated for a certain number of full charge/discharge cycles (eg 300). This means that if you use the phone until the battery is flat each time before recharging them, they will only last for 300 charges (or approximately 12 months of normal use). The battery may not even last this long if it is also subjected to warm temperatures during those 12 months.
Lithium-Ion batteries begin to degrade from the moment the battery cells are made by the battery cell manufacturer. This is due to a chemical reaction which gradually causes the internal impedance of the cells to increase and in time reduces the ability of the battery to deliver its charge. All chemical reactions are affected by heat. Each 10 degrees Celsius rise in temperature will double the rate of this reaction. For this reason, it is very important to keep you battery as cool as possible at all times, especially when it is charging.
The other main factor that can drastically reduce your battery life, is if it is left in a fully discharged state for several weeks or months. If a Lithium-Ion battery becomes too ‘flat’ it will refuse to be charged up again (even though the battery cells are probably good). If this happens you will need a new battery. For this reason do not store the battery for more than a week or so in a fully discharged state.
Under ideal conditions and if regularly topped up after use, after just 1 year, a Lithium-Ion battery will probably hold about 80% of the original capacity of a new battery.
Even if you keep your battery as cool as possible and use regular top-ups rather than always fully discharging, it can still only be expected to last for 2-3 years at the very most.
If a battery is often kept warm/hot, it may only hold around 50%-60% of its original charge after 1 year.
Charging a Lithium-Ion battery
Lithium-Ion batteries can be charged at any time, whether at a 90% charge level or only 10%. You should charge them whenever you can (do not leave them in a discharged state for more than a week or so). Charging from say the 50% charge level to the 100% charge level twice a day is much better than charging it from empty once a day.
How long will a Lithium-Ion battery last?
A battery that has not been subjected to warm temperatures or allowed to remain in a fully discharged state for more than a few weeks and has always been ‘topped-up’ rather than fully discharged every time, should last 2 to 3 years. However, at the end of this period, the battery will probably only last half as long as it did when it was new, or even less.
Lithium-Ion batteries are rated for 300-500 full discharge cycles, after which time they will deteriorate rapidly. However, if you employ a method of frequent top-ups between use (ie do not allow the battery to become almost fully discharged) then you should get 2 or 3 years of use from them. During this period however, the length of time that a full charge will last will decline by as much as half.
It should also be noted that Lithium-Ion batteries tend to ‘die’ rather suddenly when they have reached the end of their life, whilst NiMH batteries will slowly degrade when they are nearing the end of their useful life. As a Lithium-Ion battery is taken through more charge/discharge cycles, it will deteriorate much faster if mistreated, so that you may find a drastic reduction in capacity as the battery approaches the end of its useful life (eg after 300-500 full charge/discharge cycles).
A typical scenario for a battery that is exhausted, is that it will charge up in about 30 minutes but only last for 10 minutes when running the phone. This can typically happen if the battery is more than 1 year old and particularly if it has been well used and always fully discharged or not kept cool. This behaviour is an indication that the internal impedance of the battery is too high and the cells are now too degraded.
Why isn’t my battery lasting very long after only a few months of use?
Apart from the obvious reasons the reason may be in the way that you charge it. If the battery is never allowed to fully charge and then fully discharge, it will become ‘uncalibrated’ after a month or two. You can prevent this by ensuring that every month or so, you fully charge and then fully discharge the battery. After fully recharging again, the battery will be recalibrated and it may now last longer.
Note that it is recommended that you avoid fully discharging the battery every day. Top-ups are much better than using the phone continuously until the battery is flat.
Failure to re-calibrate a Lithium-Ion battery in this way will do no harm to the battery, and re-calibrating the battery does not ‘recondition’ the battery cells; it merely ensures that the phone can accurately predict how long that particular battery is going to last.