is it true that with a new laptop, if you let the battery discharge completely before recharging, the capacity will increase?

Negative


However,  with a new battery, there can be a sort of 'break in'.   What I've done with every device that has a battery is charge it up completely right away.  Then run it down, usually until the warning comes up, then charge it back up.

Batteries are a little like muscles, they do need to be exercised.  With a laptop, I'd recommend letting the battery run down to maybe 10% and then charging it up about every month.  

I did notice that my Droid's battery didn't last too long for the first week or so, but with a couple deep discharges and charges, it started lasting longer.


Adding:

Lithium batteries do not like to be stored when discharged.  They can permanently lose capacity.  It will also not hurt them to be connected to a charger frequently.

Yes. And if you have a .50 caliber, you will instantly kill every child within 100 miles upon discharging the first bullet.

Yes, you have to "exercise" them from maximum charge to full discharge periodically to establish and maintain the upper and lower limits in the chemistry.  They still haven't completely solved the "memory" problem in rechargeables.

ETA

You start out with a FULL charge before you turn it on, and then exercise it.

I don't believe that new laptop batteries (Lithium Ion) will develop a memory.

This is more of a belief people carry over from Ni-Cad days.

you should replace your laptop batteries every 12-18 mos.

How To Prolong Lithium Batteries

ETA

http://www.dansdata.com/gz011.htm

Dan's Quick Guide to Memory Effect, You Idiots

(with apologies to Stephen Notley)
Originally published 2002 in Atomic: Maximum Power Computing
Last modified 01-Apr-2008.



I have, upon occasion, heard people explain that the nickel metal hydride (NiMH) battery of cordless drill X is superior to the nickel cadmium (NiCd) battery of cordless drill Y, because NiMH has no "memory effect", but NiCd does.

I have heard other people talk about how the lithium ion battery in their laptop's better than NiMH because lithium ion has no memory effect, but NiMH does.

I have not yet heard anybody extolling the virtues of running your cordless drill from a truck battery, because lead acid batteries don't have memory effect but everything else does, but I'm sure someone has. Probably someone with an impressive collection of trusses.

People have all kinds of strange religious beliefs about the rituals that must be performed to exorcise the Memory Monster. If they were just dancing around their laptop, MP3 player or cordless drill waving incense sticks then I wouldn't care. But they're usually doing unnecessary charge/discharge cycles. Which is bad.

If you flatten a battery before you recharge it - some people flatten their batteries manually, and some chargers do it automatically - you greatly reduce the life of the pack. A given battery pack may last for 500 full cycles, or 2000 partial ones. If you're fully flattening the battery by actually using it, then fair enough. But flattening it as part of the recharging process is goofy.

"Memory effect" is now used as a general term for anything that makes a battery not deliver its full capacity. What the term originally referred to, though, is a phenomenon that's probably never actually been observed in consumer hardware.

True memory only happens in sintered plate NiCd cells (which aren't necessarily the sort of NiCd you're using, and are of course completely different from any kind of NiMH cell), and it only happens when you precisely discharge a cell to exactly the same level over and over again, and recharge it without any overcharge. True memory effect happens in satellite power systems, electronics test labs, and practically nowhere else.

Cheap trickle chargers always overcharge if you leave them long enough, and quality consumer NiCd chargers also slightly overcharge, because the slight voltage drop that happens when you do that is what they use to pick the end of the charge cycle. So even if you're using sintered plate NiCds, which you're probably not, your charger will cure memory effect anyway.

What people nowadays call memory effect is a combination of two things.

One - cell aging. Batteries don't last forever. The older they get, the less capacity they have. Live with it.

Two - "voltage depression". Voltage depression is a problem with NiCd batteries and, according to some sources, also with NiMH, and it doesn't affect the battery capacity much at all. Rather, the battery voltage drops unusually quickly as it discharges. Gadgets that monitor their battery voltage therefore think the battery's flat earlier than they should. There may be lots of capacity left at the slightly depressed voltage, but the gadget doesn't know that and flashes its "low battery" warning.

Fully discharging cells cures voltage depression, but if you fully discharge a whole battery then the stronger cells in the battery will "reverse" the weaker ones. The weaker ones go flat first, and then get charged backwards by the others. This is very bad for the weaker cells, and will kill a battery pack quick smart. So don't do it.

Fancier discharging hardware lets you set a voltage to discharge to - say, 0.9 volts per cell. A NiCd or NiMH cell that's down to 0.9 volts under moderate load has practically no charge left; it's very nearly dead flat. But stopping the discharge at that point, rather than letting the pack slump down to zero volts, should save weak cells in the pack from any significant reversal. Well, unless they're so weak that the pack's toast anyway.

There's still not a whole lot of point to doing this, though, unless you've got a scientific battery care regimen and want to start every charge from a precisely known state.

Radio control enthusiasts often cell-by-cell discharge their battery packs to nothing, in order to be able to achieve the absolute maximum super-punchy charge. But they often then go on to use that whole charge up in five minutes or less. Sometimes much less. If you've never welded a battery connector through overcurrent, then you're not in that class.

When people cycle their batteries for no reason and kill them early, they have a problem. Rechargeable batteries are hazardous waste. In most places, including here in Australia, you're not allowed to just chuck them in the bin. Instead, you're meant to take your dead batteries to a recycling centre.

Which, helpfully, doesn't exist.

Various places that sell lead acid batteries will accept them for recycling, but if you want to get rid of ordinary loose cells or consumer battery packs that use the other rechargeable chemistries, there's nowhere in Australia to go. The government requests that you just put your dead rechargeables on the mantlepiece, for the time being.

If you don't want to do that, and also don't want to break the law and make Australia's landfills even nastier than they already are, then the best idea I've been able to come up with is to subvert the Mobile Phone Industry Recycling Program. They send batteries overseas for recycling, and they're only meant to take old phones and their batteries, but I don't believe they have armed guards on their recycling bins. Since one NiCd or NiMH or LiI is much like another, you could just drop the lot in the phone battery bin when nobody's looking.

If you get busted, though, I never met you.

Not true.  I had a MacBook for 2 years that still got 4+ hours on the battery.  Replace it when it won't hold a charge, or won't last long on a charge.

I'm about to rebuild my laptop battery.  Lasts maybe 30 seconds before it shuts off.  From what I've heard you can do it for about $30 bucks which is a shitload cheaper than getting a new one.  Helps that I'm good with a soldering iron.

No.








You can do it for $30 bucks if you use the cheap chinese replacement batteries, or you can buy it already done for you in a new pack on ebay for the same price. If you want to do it right, you'll spend around $10 a battery for a name brand, non regulated li-ion. I'm assuming 18650s here.





 

Spot on.  You replace the battery when it sucks, not at a prescribed lifetime.  Some batteries are better than others, I have had some cell-phone batteries last me a couple years, while others lasted six months before a degradation in battery life.

The Mac also had a tool called iStat that monitored the battery.  It told me how many cycles it had been used for, and what it's life was relative to new capacity.  When I sold my MacBook on eBay right under 2 years old, the battery was still at 100%.  

Replacing them on a time schedule is wasting money.

thanks for the info, good thread

Ni-cad batteries run til dead and recharge til full every cycle.

Li-ion discharge until about 20% still left, then recharge. Getting significantly below 20% shortens battery life.

I should add that batteries, particularly modern lithium based chemistries are MUCH better than their predecessors.  A123 Systems makes a Lithium based cell that won't explode (when punctured), and lasts up to 7000 cycles.  

Some newer laptop batteries may last the life of the computer they are in, or at least provide enough life that the user may never need to replace it.

meh, meant to edit my above post, not quote it.

Storing them at 100% also shortens life. The ideal is 40%. That is impractical, so I'm waiting for the day when I can program the electronics in my laptops battery regulator to stop charging at 80%.



 

I'd love to.  My Computer was a house brand.  The store went tits up.
The batteries are unavailable in the states as far as I can tell.  I run both of them down about once a month.
After two+ years they're still doing fine.



Nevermind.  Amazon has some.
 

Whatever, after 18 mos most laptop batteries have degraded 25-40% - this is from both personal experience and company stats from our testing labs.

No shit?!?  I'll have to look into this.  I know nothing about this sort of thing.

You want unprotected 18650 Lithium ion batteries.  The packs tend to be a bitch to take apart, and you need to find a way to reconnect the spot welded tabs to the battery terminals.

I'm seeing a replacement battery for my Lenovo R61i for $35 shipped. The cheapest name brand 18650 I see are some Sony 2300 MaH for $40 shipped for 6, plus time to do all that soldering.



I figure, if the electronics turn out to be bad, I'll just swap the cells into my oem pack. If one of the cells turns out to be bad, I'll just replace it from my stock of $5 chinese 18650s. I've had great luck with these cheap chinese li-ions. I usually buy a stack for my cell phone and camera, and they all work as well as the oem. ymmv and all that. Either way,