Why Must Charge Battery for 8 Hrs?


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weekh

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Sep 6, 2004
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#1
Howcome all the salesman advice us to charge the battery for 8 hours during the first charge?
What's the rationale behind this? I've never seen this mentioned in any of the user manual.
 

Clown

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Mar 24, 2003
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#2
this is an old rule for nicads and lead acid batteries.

Lithum batteries nowadays prefer to be maintained between 50% power and 100%. no need for 8hr charging mumbo jumbo unless you're using specialized battery calibrator or conditioner.
 

#3
Arh.... That is a misunderstanding with most people nowadays... Let me share my knowledge of battery with you....

In the older days, the battery we are using is call Nickel-metal cells which have lower power capacity, shorter life time and voltage depression aka MEMORY EFFECT. The 8hours first charge come to the picture because memory effect of Nickel-metal battery cells.

So what is memory effect??

In a simple term, it's an effect that causes Nickel-metal cells to hold lesser charge if you didn't charge your battery properly.
So what do I mean by charging your battery cells properly??
It means to fully use up ALL the power in the battery cell and charge it again. If you left your battery with half of it's power remaining and you start to charge it, the power capacity of the Nickel-metal cells will drop to half over a period of time. Therefore to improve the capacity of the old Nickel-metal cells, salesman will usually advice people to charge your battery for 8 hours during the first charge, so to push the battery capacity to the max.

HOWEVER, Nickel-metal rechargable batteries have been replaced by Lithium-ion batteries over the past years. This new form of cell is now very widely used. Example of them are your laptop, handphone, camera rechargable batteries. It's able to contain more power than Nickel-metal, longer life, and most importantly, NO MEMORY EFFECT...

In another words, you don't have to do that 8 hours first charge anymore and you can charge the battery whenever you are happy. In fact, the property of Lithium-ion batteries prefers you to keep it fully charge so to improve it's life spend. Why do i say that? Lithium-ion batteries usually is able to charge for around 1200 cycles. From full charge to flat battery is 1 cycle. So if you left 80% of your battery and you charge it, it will takes 4 times of charging to reach 1 cycle. Got it?? =D
 

Ninja23XX

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Jan 24, 2009
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#4
Arh.... That is a misunderstanding with most people nowadays... Let me share my knowledge of battery with you....

In the older days, the battery we are using is call Nickel-metal cells which have lower power capacity, shorter life time and voltage depression aka MEMORY EFFECT. The 8hours first charge come to the picture because memory effect of Nickel-metal battery cells.

So what is memory effect??

In a simple term, it's an effect that causes Nickel-metal cells to hold lesser charge if you didn't charge your battery properly.
So what do I mean by charging your battery cells properly??
It means to fully use up ALL the power in the battery cell and charge it again. If you left your battery with half of it's power remaining and you start to charge it, the power capacity of the Nickel-metal cells will drop to half over a period of time. Therefore to improve the capacity of the old Nickel-metal cells, salesman will usually advice people to charge your battery for 8 hours during the first charge, so to push the battery capacity to the max.

HOWEVER, Nickel-metal rechargable batteries have been replaced by Lithium-ion batteries over the past years. This new form of cell is now very widely used. Example of them are your laptop, handphone, camera rechargable batteries. It's able to contain more power than Nickel-metal, longer life, and most importantly, NO MEMORY EFFECT...

In another words, you don't have to do that 8 hours first charge anymore and you can charge the battery whenever you are happy. In fact, the property of Lithium-ion batteries prefers you to keep it fully charge so to improve it's life spend. Why do i say that? Lithium-ion batteries usually is able to charge for around 1200 cycles. From full charge to flat battery is 1 cycle. So if you left 80% of your battery and you charge it, it will takes 4 times of charging to reach 1 cycle. Got it?? =D
Memory Effect? I think you got the terms wrong.
 

ricohflex

Senior Member
Feb 24, 2005
3,353
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#6
found this in another forum

Posted by simon69c
The first few charge rule isn't about "memory effect" anyway - it is to ensure that all the cells get properly initialised as they won't all get charged properly within the normal 2 hour charge cycle. The trickle charge for the extra couple of hours ensures that all the cells do get fully charged and significantly improves the subsequent performance of the battery.
 

lkkang

Senior Member
Jan 6, 2007
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#8
Mr Wee,

There is no much diff between charging or discharging NiCd or NiMH or Li-ion or even Li-polymer.

For such extended charging ( normally slow charge ). We called it formatting a battery. It is necessary to "train" the new cells, so that they know what their maximum capacity are. If you do not train them well initially, they will not show their full capacity or rather designed full capacity.

good luck
Billy
 

Ninja23XX

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Jan 24, 2009
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#9
I work in the solar industry and there are various explainations to how to condition a new bttery.

Personally from my experience this would be my say:

As recommended by the factory, a usual lithium ion battery only needs average 1-3 hours to charge, depending on the battery capacity and charger output current level.


However, why do salesmen/store owners, always ask you to charge your new battery devices for 8 hours?

This is due to a chemical process in the battery called sulfation. In the past, be it any battery, it was prone to sulfation. Sulfation is the process where a layer sulfate grows on the cells, reducing battery life and the ability to hold a higher charge level. This is very prone in lead-acid batteries. It's also occurs in other battery types as well.

Thus back then, it was advisable to charge your new battery for 8 hours. Over charging will remove the sulfation and increase the battery to it's original charge level.

However, batteries today are much more advanced and they have minimised sulfation levels. However, when ever a battery is discharged and not used for a long period of time, sulfation will occur.


If you still don't understand what i'm trying to say, here's a little example.


Example:

You buy an ipod. But you don't know how long the ipod had been sitting in the warehouse for. An un-used battery would always start to discharge naturally into the air or any other means. Thus minimal sulfation might be present in the battery because new batteries are better designed to have minimal sulfation.


Thus it's usually said to charge the battery for 8 hours. Well, my opinion is that take a look at the product recommended time for a full charge, then add another 2-3hours. That should be quite alright for you to condition your battery.


As for me, i usually charge my battery for 12 hours. The battery won't overcharge as the charger would usually cut of the electricity supply to the battery once the batter has sustained a full charge. Quite contradicting, as you may ask, if the charger cuts of supply once full charge, then charging a new battery for 8 hours is useless. I felt that way too. But i did some test on 2 identical batteries. Same batch processed. I charged one for the recommended full charge time as from the manufacturer (about 1-2hours) and i did the myth charge time(8 hours) for the other.


My results showed that the battery that had been charged for 8 hours lasted significantly longer than the battery that was charged at the recommended charge time period of 1-2 hours.


All the tests we ensured fair with a control setup as well. The battery charged for 8 hours reaped in an hour more in usage time compared to the other battery. The battery used was a lithium ion battery. Those used in your ipods, music devices, handphones, etc.

So for me, it does conclude my questions. As for the rest, it can be up to personal preferance as to how long you would like to charge the new battery.
 

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szeping

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Jan 13, 2008
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#10
My results showed that the battery that had been charged for 8 hours lasted significantly longer than the battery that was charged at the recommended charge time period of 1-2 hours.
Then have you tried to fully charge back (8 hours) the battery that had only been charged for 1~2 hours? I wonder will it simulate the cell to stretch to maximum capacity again... Or there's only one chance to do it right at the first charge?
 

Ninja23XX

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Jan 24, 2009
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#11
Have not really tried that. Good tip anyway. Thanks. But from what i know, you cannot recondition a battery once it has went through the conditioning process. Correct me if i'm wrong.:)

Because i used the batteries as per normal. The battery that was charged 8 hours still holds a longer period than the battery that was charged 1-2 hours. Till today.

So i believe, it has reached the battery charge hold level state.
 

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muvouser

New Member
Oct 2, 2006
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#12
nonsense. Modern charger for lithium ion batt does NOT trickle charge. Once it sense its charged. The charger CUT-OFF totally. Many kanna misled put their device for 8 - 12 hours that does nothing!

I know it because I have done an experiment on my hand phone charger connecting my multimeter in series on the positive lead (measuring current flow) and nothing flows thru when the charger cut off after 1-2 hours.

Use your blain, the charging indicator on your device already stopped and you still wan to believe it is still charging? hahaha
 

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szeping

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Jan 13, 2008
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#13
Have not really tried that. Good tip anyway. Thanks. But from what i know, you cannot recondition a battery once it has went through the conditioning process. Correct me if i'm wrong.:)
You are welcome. I'm curious to know the result also, but have totally no idea how it works, despite a few small chapters in physics during sec time.
 

Ninja23XX

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Jan 24, 2009
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#14
nonsense. Modern charger for lithium ion batt does NOT trickle charge. Once it sense its charged. The charger CUT-OFF totally. Many kanna misled put their device for 8 - 12 hours that does nothing!

I know it because I have done an experiment on my hand phone charger connecting my multimeter in series on the positive lead (measuring current flow) and nothing flows thru when the charger cut off after 1-2 hours.

Use your blain, the charging indicator on your device already stopped and you still wan to believe it is still charging? hahaha
Can you be a little less rude, and i already mentioned in my reply that the charger cuts of supply once the battery is fully charged. Please go and read carefully.

I did the test and it proved. You can have all the theory you want, but sometimes, in practical, things do not work the same as you plotted on theory. And please don't feel that you alone has a multimeter in this world. I do have one as well. A multi meter is nothing compared to other battery testing devices.
 

Last edited:
#15
nonsense. Modern charger for lithium ion batt does NOT trickle charge. Once it sense its charged. The charger CUT-OFF totally. Many kanna misled put their device for 8 - 12 hours that does nothing!

I know it because I have done an experiment on my hand phone charger connecting my multimeter in series on the positive lead (measuring current flow) and nothing flows thru when the charger cut off after 1-2 hours.

Use your blain, the charging indicator on your device already stopped and you still wan to believe it is still charging? hahaha
Wooo... relax dude... You sound pretty hash... :think:
 

splim

New Member
May 6, 2006
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#16
Can you be a little less rude, and i already mentioned in my reply that the charger cuts of supply once the battery is fully charged. Please go and read carefully.

I did the test and it proved. You can have all the theory you want, but sometimes, in practical, things do not work the same as you plotted on theory. And please don't feel that you alone has a multimeter in this world. I do have one as well. A multi meter is nothing compared to other battery testing devices.
Just want to clear my doubt, did you used one of the battery immediately after it is fully charged (1-2hrs) ? and the other after 8 hours ?
 

Ninja23XX

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Jan 24, 2009
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#17
Just want to clear my doubt, did you used one of the battery immediately after it is fully charged (1-2hrs) ? and the other after 8 hours ?
Yupp, yes i did. Both batteries were used immediately after the (1-2hours) charge time or the 8 hours charge time.

Reason being, if i waited for the other battery to charge within 8hours, the battery that was charged in a shorter period of time will start to discharge through the air. So i used the batteries once charged. I took note of the time & date for each battery.
 

#18
Have not really tried that. Good tip anyway. Thanks. But from what i know, you cannot recondition a battery once it has went through the conditioning process. Correct me if i'm wrong.:)

Because i used the batteries as per normal. The battery that was charged 8 hours still holds a longer period than the battery that was charged 1-2 hours. Till today.

So i believe, it has reached the battery charge hold level state.
Once had a handphone battery which I only charged 2hrs for the first charge (was too excited to use it then)..and the battery only lasted me one day of use (standby mode with minimal sms-ing). Bought another battery, and stupidly charged it for 2hrs again for first charge, and like the first, it didn't last. Bought a 3rd battery and did a 12hour charge and *poof*..my phone can finally last 5 days on a single charge. Have tried to "recondition" the first two batteries by doing 12hour charges, but failed.

Interestingly, my current mobile phone (nokia E61) battery works in a weird way. I need to charge it exactly 2hrs 20mins to get optimal results (6~7days). If I forget to switch off the charger after the 2hr20mins, the battery only lasts 2days. :confused:
 

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