How should I charge my laptop battery?

[newbestv]

Which is better: to charge the laptop battery only when its empty, or to use the charger whenever its available? I heard very various opinions about this issue, so I want a definitive answer. I have an Asus K61IC.

[redwudz]

I just leave my charger plugged in all the time to my Asus laptop as I rarely run it just on the battery. I've done that with my last few laptops. I don't think it makes much of any difference in the battery life.

If I recall, the older Ni-Cad batteries had a 'memory' and needed to be discharged completely before recharging. But laptops use Lithium Ion batteries now and it's usually recommended not to discharge them below 50% before recharging. http://www.techrepublic.com/blog/helpdesk/the-care-and-feeding-of-li-ion-batteries/124

And I don't know if you will get a definitive answer. Several sites had different information than the one above.

And welcome to our forums.

[ranchhand]

These batteries only last 2/3 years anyway and then need to be replaced. So don't worry about it.

[Capmaster]

The old Ni-Cd batteries demanded you discharge fully before recharging, for the reason redwudz gave. They love to be deep-discharged periodically, and have an actual deep-cycle reconditioning procedure to renew them. Ni-MH are similar, although with not nearly as bad a "memory" effect.

Li-Ion (and Li polymer) batteries in your laptop or cell phone, like the lead acid battery in your car, prefer to be "float" charged - being attached to the charger all the time and not allowed to be deep-discharged very often.

[budwzr]

My Toshiba laptop manual says to fully discharge the battery(Li) once a month, and not to leave it on A/C power more than eight hours if not in use.

I have AGM batteries in my RV, and what Capmaster says is what I do. No deep cycles, fully float for 24hrs, then disconnect. They're still like new after eight years. They can sit disconnected indefinitely and hold a full charge. Not so with lead-acid batts.

And to further complicate things, my Sony Camcorder manual says to completely discharge the battery(Li) when not in use for a long time.

WTF!

P.S. I once had an HP(Li) laptop plugged in all the time and it cooked the battery. I didn't know it until I took the laptop on the road and it was DOA.

P.S.S. I have an old Norelco electric shaver with NiCads that wouldn't hold a charge so I charged it/Ran it down about five times, and little by little it came back to life.

[Hoser Rob]

My Toshiba laptop manual says to fully discharge the battery(Li) once a month, and not to leave it on A/C power more than eight hours if not in use...

My Acer manual says something similar. They recommend deep cycling the battery 3 times in a row occasionally, meaning letting it discharge until critical level then recharging. They didn't say how often do do this.

[mike20021969]

and not to leave it on A/C power more than eight hours if not in use.

Yes, you should not leave a laptop battery charging forever. You will wreck it's usable life.

Either remove the battery when fully charged or, easier still, pull out the power/charging cable and power via the battery.

Set the Low battery alarm to 10%, then when it sounds charge the battery again.

If you never use the battery full stop, remove it.

[Capmaster]

[QUOTE=mike20021969;2246859]

and not to leave it on A/C power more than eight hours if not in use.

Yes, you should not leave a laptop battery charging forever. You will wreck it's usable life.

True, but ...

From battery university:

Li-ion cannot absorb overcharge, and when fully charged the charge current must be cut off. A continuous trickle charge would cause plating of metallic lithium, and this could compromise safety. To minimize stress, keep the lithium-ion battery at the 4.20V/cell peak voltage as short a time as possible.

The laptop manufacturers know people's habits of leaving them plugged in all the time, and have designed them to allow this without damaging the battery.

Modern laptops have threshold chargers for their internal batteries. They don't allow any current to flow into the battery unless its voltage is below the set point. This is very easy to design and implement, and all reputable brands utilize this type of voltage-limited charging. Owner's manuals don't always reflect this.

For example, here's the little notice mine gives on-screen:

[pearlblack15]

This is what lenovo has to advise.

[edong]

@newbesttv - so there's your definitive answers

[Baldrick]

@newbesttv - so there's your definitive answers

Newbestv banned. Just spamming a battery site.