Why Must Charge Battery for 8 Hrs?

[Ninja23XX]

hmmm it happens no matter what charger i use..

Then i guess, it's just the battery's optimal point. But it's strange.

 

[splim]

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.

My feeling is that, it's not so much on the continuous charging for 8 hours, but rather, it should be left alone after it's fully charged for a period of time to stabilized before discharging it.

So telling people to charge for 8 hours is easier than telling them to charged it then take out leave it alone for 8 hours before using it.

Unless there's proved that the charger continuously doing top-up charging after it is fully charged.

 

[Ninja23XX]

My feeling is that, it's not so much on the continuous charging for 8 hours, but rather, it should be left alone after it's fully charged for a period of time to stabilized before discharging it.

So telling people to charge for 8 hours is easier than telling them to charged it then take out leave it alone for 8 hours before using it.

Unless there's proved that the charger continuously doing top-up charging after it is fully charged.

When you charge your battery for 8 hours, your battery gets full charged in 1-2 hours, then it will slowly discharge and re charge, discharge and recharge. Thus at the end of the 8 hours, you touch the battery, it's not warm at all. Because it discharges a little then charges back.

Where as a battery charged for 1-2 hours will feel warm and it will start to discharge with the air because it's still active and heat helps to accelerate the chemical process.


The modern day battery does not need to stabilize. So my test is still accurate.

 

[Canew]

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

Huh! Like that? All the while, I though a charge is a cycle itself, with no relation to the level of battery left.

 

[muvouser]

err. .... i have a multimeter and I did my tests to prove it.

You claimed you had one but you did not do any tests. Then you chide me and say I think I am not the alone one with multimeter? I am puzzled why you even bother to bring up that you had one and but did no tests.

Current flow shows nothin (0.00A) when charging had stopped. Then you say "but sometimes, in practical, things do not work the same as you plotted on theory". :bsmilie:

Its is not about who got multimeter, it is about who know how to use their tool and apply the fundamentals dude.

Peace.

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.

 

[muvouser]

http://www.google.com/search?q=lith...ie=UTF-8&oe=UTF-8&sourceid=ie7&rlz=1I7GGLL_en

http://www.batteryuniversity.com/partone-12.htm


http://www.powerstream.com/li.htm

 

[NeTHaCk]

i dont understand why some people have to get so defensive . its not like battery companies are paying you to tell others whats right and wrong.

for me, i'll charge normally till the battery is "full" and then use it till it goes flat. out of the box, if manual says charge 4hrs , i'll charge 4hrs and start using immediately.

let the battery goes flat then charge fully but this time, longer.

 

[zekai]

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 explain why nokia BP6M batteries get bloated during overcharging?

 

[muvouser]

Precisely! No device with lithium ion batts in the world now will tell you to charge first-time use for 12 hours. People have not been reading their instructions booklets!

i dont understand why some people have to get so defensive . its not like battery companies are paying you to tell others whats right and wrong.

for me, i'll charge normally till the battery is "full" and then use it till it goes flat. out of the box, if manual says charge 4hrs , i'll charge 4hrs and start using immediately.

let the battery goes flat then charge fully but this time, longer.

 

[ricohflex]

Buy two pieces of the same brand/model/type of batteries. Say, price is $X each.
Don't follow the 8 hour first charge rule for one.
Follow the 8 hour rule first charge for the other.
See what happens.
No diff? Good for you.
Got diff? You paid $X for the lesson to gain some battery knowledge based on real life experience. And not other Forums member's theories, imagination and second hand knowledge from the Internet (on the Internet there are many contesting opinions - in some cases, even mistaken statements and we should not take it as fact or the truth)

 

[kkcharles82]

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....

I do not think ipods uses lead-acid batteries that succumb to sulfation, they use li-ion, the example you use regarding ipods is both misleading and wrong, please edit your post accordingly. Besides, any amount of sulfation in a lead-acid battery is devastating, and very difficult to reverse. In my research, it is almost impossible, with the exception of a few exotic charge methods to reverse sulfated lead-acid batteries.

Besides, sulfation only happens in lead-acid batteries as there is sulfuric acid in there, no other battery chemistry uses that.

 

[Ninja23XX]

In my reply did i mention in anywhere that ipod's use lead acid battery? :bsmilie:

 

[kkcharles82]

please read my edited post with highlighting.

 

[Ninja23XX]

please read my edited post with highlighting.

I stil didn't mention about ipods using lead acid batteries. Never mind.

 

[Ninja23XX]

err. .... i have a multimeter and I did my tests to prove it.

You claimed you had one but you did not do any tests. Then you chide me and say I think I am not the alone one with multimeter? I am puzzled why you even bother to bring up that you had one and but did no tests.

Current flow shows nothin (0.00A) when charging had stopped. Then you say "but sometimes, in practical, things do not work the same as you plotted on theory". :bsmilie:

Its is not about who got multimeter, it is about who know how to use their tool and apply the fundamentals dude.

Peace.

You have your explaination, i have mine. You were rude with your replies. If you had something to say, do it nicely. It's not that i did something to you that you have to bear a grudge.

 

[redmonsoon]

Educational thread,thks.
But can't believe I actually read every post... Not that it matters much to me.:bsmilie:

 

[matthew]

can you explain why nokia BP6M batteries get bloated during overcharging?

All Lithium chemistry batteries will tend to do that if you overcharge them, that's why it's important to use the correct charger.
I'm not sure of the chemistry behind it.
A modeler who has overcharged his model batteries several times (using home built 'fast' chargers) says they tend to still work afterwards but their life was shorter.

 

[Royale With Cheese]

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

Nice! That is good information for the masses :thumbsup:

I knew all along that Lithium batteries last longer if you just kept re-charging but didnt know the whole story behind it, thanks for the heads up!

 

[Royale With Cheese]

You have your explaination, i have mine. You were rude with your replies. If you had something to say, do it nicely. It's not that i did something to you that you have to bear a grudge.

hmmm....

Educational thread become so drama :bsmilie: Quite entertaining in the office I must say

 

[WuffRuff]

Huh! Like that? All the while, I though a charge is a cycle itself, with no relation to the level of battery left.

I just want to affirm that what he has said regarding charge cycles is correct.
I think I read that in the Macbook's manual. :thumbsup: