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DoD: Depth of Discharge for li-Ion batteries

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okishead
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(Last edited by okishead; 20th December 2011 at 03:36 PM.) Reason: wrong link
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Cool DoD: Depth of Discharge for li-Ion batteries

I was browsing the web in search for an answer for a simple question:
"How to properly charge your li-ion battery and increase battery life?"
This is what I got so far.

1. Battery life cycle: Any Li-Ion battery life is measured based on how many times can you discharge it from 100% to 0%. Normally the figure is 300-500 times and it depends on a factor called DoD (Depth of Discharge).

2. Depth of Discharge (DoD): Quite self-explanatory thing. If you have 20% charge left, it means that DoD=80%. The higher is the DoD the lower is your battery life cycle.
Comparison table is here:

So, here's the answer to the painful question "Why should not I discharge my li-ion to 0%?" The answer is - your battery will die faster. I'm trying to get used to put both my OEM and Mugen Power batteries to charge right after my Nexus informs about 15% charge left.

3. Deep discharge: Not allowed for li-ion batteries. This is pretty interesting: Li-ion should never be discharged too low, and there are several safeguards to prevent this from happening. The equipment cuts off when the battery discharges to about 3.0V/cell, stopping the current flow. If the discharge continues to about 2.70V/cell or lower, the battery’s protection circuit puts the battery into a sleep mode. This renders the pack unserviceable and a recharge with most chargers is not possible. To prevent a battery from falling asleep, apply a partial charge before a long storage period.
Also: Do not recharge lithium-ion if a cell has stayed at or below 1.5V for more than a week.

So, what I got from this section is - when I get to 0%, I will not try to switch on my phone again because that can damage my battery.


4. Don't charge in small portions: This is important in a long term for higher capacity batteries. If you use an extended 3000+mah battery it's important to use the whole capacity of the battery to avoid aging of cells that are not used. It's recommended to charge your extended battery to 100% from time to time.

5. Recycle your batteries

I think this article here could be updated a little with these.
http://forum.xda-developers.com/showthread.php?t=518861

Sources:
http://mugen.tv/?p=690
http://batteryuniversity.com/learn/a..._ion_batteries
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7_michel
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Most smartphone maintain a charging current even after the 100% charge level is reached. I think that this should also have an effect on battery life....
What is your opinion ?
 
okishead
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Quote:
Originally Posted by 7_michel View Post
Most smartphone maintain a charging current even after the 100% charge level is reached. I think that this should also have an effect on battery life....
What is your opinion ?
I think that in this case battery is protected with the battery's controller that only opens the current when the discharge level is below a certain point. That is why it's safe to keep your phone on charge overnight.
 
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This part is wrong

. Don't charge in small portions: This is important in a long term for higher capacity batteries. If you use an extended 3000+mah battery it's important to use the whole capacity of the battery to avoid aging of cells that are not used. It's recommended to charge your extended battery to 100% from time to time.

if you notice if you always discharge to 50% you will get 1500 discharge cycles, that's not 1500 discharges to 50%, but 1500 full charge cycles, which would be recharging it to 100% twice from 50%, so by going from 100% and always recharging at 50% you get 50% more life out of your battery. Li-ion batteries last longer when not full discharged regularly, sadly usage of a smartphone is not very well suited for keeping it at a high charge as most users, even me, don't charge multiple times a day but try to optimize their phone so they only have to recharge once a day at night, which is the reason I like removable and replaceable android phone batteries

Li-ion batteries also are smart in that they intelligently charge and discharge cells so that certain cells won't age more than others, so you don't have to worry about that.

Also this is for another poster, the batteries have protection circuits to ensure that you don't overcharge your phone, so leaving it on the chargers after 100% I charge my phone each night to 100% and it doesn't do any damage to the battery.
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okishead
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Quote:
Originally Posted by movielover76 View Post
This part is wrong

. Don't charge in small portions: This is important in a long term for higher capacity batteries. If you use an extended 3000+mah battery it's important to use the whole capacity of the battery to avoid aging of cells that are not used. It's recommended to charge your extended battery to 100% from time to time.

if you notice if you always discharge to 50% you will get 1500 discharge cycles, that's not 1500 discharges to 50%, but 1500 full charge cycles, which would be recharging it to 100% twice from 50%, so by going from 100% and always recharging at 50% you get 50% more life out of your battery. Li-ion batteries last longer when not full discharged regularly, sadly usage of a smartphone is not very well suited for keeping it at a high charge as most users, even me, don't charge multiple times a day but try to optimize their phone so they only have to recharge once a day at night, which is the reason I like removable and replaceable android phone batteries

Li-ion batteries also are smart in that they intelligently charge and discharge cells so that certain cells won't age more than others, so you don't have to worry about that.

Also this is for another poster, the batteries have protection circuits to ensure that you don't overcharge your phone, so leaving it on the chargers after 100% I charge my phone each night to 100% and it doesn't do any damage to the battery.
The "charge in small portions" is correct. What I meant is this if your battery is charged up to 50% and you keep charging it to 75% and never up to 100%, that is not good practice. Experience with new li-ion batteries shows that once or twice in a week it's important to charge it up to 100%.
Regarding the protection in the batteries - it works against overcharging, but sadly, not against overdischarging. Your phone will allow you to switch it on one or two times after the indicator shows the zero level. It's important NOT to do that because that damages chemistry in any type of batteries including li-ion.
 
votinh
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Quote:
Originally Posted by okishead View Post
The "charge in small portions" is correct. What I meant is this if your battery is charged up to 50% and you keep charging it to 75% and never up to 100%, that is not good practice. Experience with new li-ion batteries shows that once or twice in a week it's important to charge it up to 100%.
Regarding the protection in the batteries - it works against overcharging, but sadly, not against overdischarging. Your phone will allow you to switch it on one or two times after the indicator shows the zero level. It's important NOT to do that because that damages chemistry in any type of batteries including li-ion.
1. Read this: http://batteryuniversity.com/learn/a..._ion_batteries
"Li-ion does not need to be fully charged, as is the case with lead acid, nor is it desirable to do so. In fact, it is better not to fully charge, because high voltages stresses the battery."

2. This: http://www.centralhobbies.com/instru...l/lithium.html
1. Charge often. Don't try to fully discharge the battery packs frequently. This only adds strain. Several partial discharges (regular use) with frequent recharges are better for lithium-ion than one total discharge.

Confusing, yes, sure is.
Basically, for Li-Ion battery.
1. NEVER allow deep discharge (to 0%). Once in a while, I still get an article on web suggesting let the battery completely discharged. Hmmm.
2. Fully charge (to 100%) is not good either, partially charge is better. Confuse enough?
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Yes confusing!!!

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