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#11901 - 09/20/10 01:19 PM Should leave cord in laptop?
kevs Offline


Registered: 12/07/09
Being that you battery only has a certain number of cycles, should one leave the power cord in if possible?

I ask because I also know it's good to drain the battery.

is having the cord in then extending or reducing life of the battery?

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#11902 - 09/20/10 01:51 PM Re: Should leave cord in laptop? [Re: kevs]
alternaut Offline

Moderator

Registered: 08/04/09
You can leave the power cord attached whenever possible, but if you do make sure to calibrate the battery regularly, let's say once a month. If you don't know how, use 'Mac Help' to find the proper battery calibration procedure for your 'Book.

Calibration drains the battery as part of the procedure, and you can use heavy power draining activities like running a WiFi scan utility set to scan every second, and/or playing a movie DVD to drain the battery quickly. If you calibrate at night, the 'Book’s battery can sit drained for the time required while you sleep, and is ready to roll (and recharge) the next morning.

In addition to calibrating it probably won't hurt to pull the plug every other week and run the battery down, but I’m not sure that’s really necessary.
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#11904 - 09/20/10 07:14 PM Re: Should leave cord in laptop? [Re: alternaut]
kevs Offline


Registered: 12/07/09
A
are you saying you can leave it attached or you should leave it attached??

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#11905 - 09/20/10 07:16 PM Re: Should leave cord in laptop? [Re: kevs]
kevs Offline


Registered: 12/07/09
PS
http://docs.info.apple.com/article.html?path=mac/10.4/en/mh2339.html

calibrating is a fancy way to do what I'm already doing, draining the battery till it dies and recharging.

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#11906 - 09/20/10 07:38 PM Re: Should leave cord in laptop? [Re: kevs]
alternaut Offline

Moderator

Registered: 08/04/09
I meant to say that you can leave the power cord attached, NOT that you should all of the time. The battery needs the workout, hence the drain cycles. And talking about drain/charge cycles, calibrating the battery does more than just drain it. The two are not identical or interchangeable.
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#11909 - 09/21/10 06:42 AM Re: Should leave cord in laptop? [Re: alternaut]
kevs Offline


Registered: 12/07/09
I want to know:
Does leaving the cord save battery cycles?
is it better to have cord in, or never keep it in unless your are charging to full.

The link on calibrating said nothing beyond just drain, and recharge.

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#11910 - 09/21/10 07:10 AM Re: Should leave cord in laptop? [Re: kevs]
kevs Offline


Registered: 12/07/09
PS,
if you are in cafe for 2hours should you use battery or use cord? same question for the house, that what I'm asking. If using cord are you extending the life cycles of the battery. is the batter not being used? it that ok on the battery? saving life of batter?

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#11911 - 09/21/10 07:34 AM Re: Should leave cord in laptop? [Re: kevs]
alternaut Offline

Moderator

Registered: 08/04/09
Occasional corded or cordless use as you describe doesn’t affect battery life, but you shouldn’t run a laptop from the wall socket all of the time. That won’t help but hurt battery life in the long run. Likewise, NOT using a laptop for prolonged periods of time is also deleterious to battery life. From Apple’s recommendations on Notebook battery use:

Apple does not recommend leaving your portable plugged in all the time. An ideal use would be a commuter who uses her MacBook Pro on the train, then plugs it in at the office to charge. This keeps the battery juices flowing. If on the other hand, you use a desktop computer at work, and save a notebook for infrequent travel, Apple recommends charging and discharging its battery at least once per month.
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#11921 - 09/21/10 02:35 PM Re: Should leave cord in laptop? [Re: kevs]
joemikeb Offline
Moderator

Registered: 08/04/09
Loc: Fort Worth, Texas
FWIW I have read, but I cannot personally confirm that leaving a laptop plugged in all the time actually results in literally tens of thousands of "mini" discharge/recharge cycles which is why it is not recommended to leave it plugged in all the time.

You might check out Battery University for definitive information about all types of rechargeable batteries including charging recommendations for each specific battery type.
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#11924 - 09/21/10 03:24 PM Re: Should leave cord in laptop? [Re: joemikeb]
artie505 Online


Registered: 08/04/09
> [...] leaving a laptop plugged in all the time actually results in literally tens of thousands of "mini" discharge/recharge cycles [....]

I don't know about tens of thousands, but I can attest to the fact that the battery of a plugged-in Mac discharges about 5-6% and then recharges.

I've never attempted to determine a time interval, but I do know that the battery of my early 2009 MacBook discharges far more slowly than did the battery of my late 2004 iBook G4.
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#11925 - 09/21/10 04:15 PM Re: Should leave cord in laptop? [Re: artie505]
kevs Offline


Registered: 12/07/09
Joe,
I thought you were going to save the day here?
in short -- if your battery has 200 cycles, will keeping it plugged in at the internet cafe instead of using the battery (which is full), prolong the life of the battery??
that's my question.

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#11941 - 09/22/10 09:46 AM Re: Should leave cord in laptop? [Re: kevs]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: kevs
I want to know:
Does leaving the cord save battery cycles?
is it better to have cord in, or never keep it in unless your are charging to full.

The link on calibrating said nothing beyond just drain, and recharge.


(1) if you go a long period of time without discharging the battery through use, you will ruin its ability to hold a long lasting charge. Batteries that have gone a half a year without charging may have a runtime measured in seconds as a result of not being exercised regularly. or they may appear to run well at first and then suddenly remaining power estimates drops from 2 hrs to 15 minutes over the coarse of a few minutes. The general rule is that battery runtime is determined by how much it's used to being discharged. If you never discharge it, its runtime will change to reflect that.

(2) cycle count is only increased through charging. if you never discharge the battery, the cycle count does not advance. discharge/recharging it periodically ("recalibrating"/"periodic cycling"/"etc") will slowly increment your cycle count. Avoiding exercising your battery to preserve cycle count is a bad idea because it can lead to sudden failures as described in #1. But on the other hand, overly-frequent exercising is wasting your cycle counts needlessly. Half a discharge followed by fully recharging it, twice, would add one cycle. (it counts partial cycles)

(3) except through defects, batteries need to be replaced in one of two cases. either when you have not exercised the battery (see #1) enough and the runtime has become unacceptably short (or won't run on battery at ALL) or in the event you've simply used the battery enough to wear it out due to cycles (see #2)

(4) A cycle count of over 300 is standardly referred to as "consumed". A cycle count over 100 is "used". Used batteries should still be useful but will have a noticeably shorter runtime on battery that they did when they were new. Consumed batteries will have a very short runtime, usually 15-25 minutes. You can view your battery's current cycle count in system profiler under Power. There is no way to reset your cycle count, it's like the odometer in your car. Apple ends the warranty on your battery when the cycle count passes 100, and extended warranty (applecare) does not apply to batteries ever. Batteries are like brake pads on your car. You should expect to replace them occasionally over the lifetime of the product.
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#11943 - 09/22/10 10:55 AM Re: Should leave cord in laptop? [Re: Virtual1]
kevs Offline


Registered: 12/07/09
"if you never discharge the battery, the cycle count does not advance"

V -- SO then keep it plugged in quite a bit? and only let it fully drain out one time month for maintenance?

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#11944 - 09/22/10 11:02 AM Re: Should leave cord in laptop? [Re: kevs]
kevs Offline


Registered: 12/07/09
PS just looked my cycle number is at 10 and just put new battery in few weeks ago! I was draining it down a lot, so now I wont do that except 1x month.

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#11945 - 09/22/10 02:01 PM re: adapters and batteries [Re: kevs]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: kevs
"if you never discharge the battery, the cycle count does not advance"

V -- SO then keep it plugged in quite a bit? and only let it fully drain out one time month for maintenance?


That's what I do. I treat my battery as a consumable limited resource, I don't run it on battery when I don't have to. I actually need to be able to run extended periods sometime for onsite work though so I have two. About once a month I unplug and let it get to low power warning, let it charge up, and then swap it with the twin in the bag. This keeps both batteries conditioned, and the one in the bag charged.

(I also treat disk burning ability the same way - slot load drives are limited use)

With this usage I've never actually gotten a battery above 200 cycle count, which I find quite surprising. But when I do sell my computer at upgrade time, it always goes with two good batteries, which increases its resale value.

I'm not saying you should be afraid to use it on battery - just that you shouldn't use it on battery when power is available. To that end I also have a second power adapter I keep in my laptop bag. With this I avoid the problem of forgetting to bring my pack with me, and the wear and tear of constantly packing and unpacking the adapter. (NEVER wrap the cord around the cord ears on the pack!)

Originally Posted By: kevs
PS just looked my cycle number is at 10 and just put new battery in few weeks ago! I was draining it down a lot, so now I wont do that except 1x month.


Yep I could see it climbing that fast if you use it on battery frequently. I probably don't use mine as a laptop so much as a desktop - this mbp is my primary computer and now spends almost all its time plugged in either here or at work. (I take it to work) The main time it runs on battery is when I'm somewhere else with the laptop in the bag and need to get it out.
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#11946 - 09/22/10 03:26 PM Re: re: adapters and batteries [Re: Virtual1]
kevs Offline


Registered: 12/07/09
THANKS V.
good. I was using battery all the time even at home. Mainly I thought using it with the cords drains it anyway, and it more comfortable not having a cord around.

Now I'll use the cord all the time.

the thin part of the cord wraps around those cord ears no? that's what it's there for no?
How much time do you get on a batter?

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#11950 - 09/23/10 02:38 AM Re: re: adapters and batteries [Re: Virtual1]
tacit Offline


Registered: 08/03/09
Loc: Portland, Oregon, USA
Originally Posted By: Virtual1
(I also treat disk burning ability the same way - slot load drives are limited use)


I've heard that, but it actually hasn't been my experience. The slot-loading drive in my MacBook has burned a startlingly large number of CDs.

When I first got the computer, it would burn CDs but not DVDs; it shipped from the factory with a defective drive. Apple replaced it for me under warranty. Since then, the drive has been awesome.

The company I'm a part owner of ships the user manual for our products on CD, and I usually burn the CDs myself. In addition, we produce multimedia sales CDs that are tuned to different distributors of our product, and ship stacks of those CDs to the distributors. In one two-month period, I burned, without exaggeration, more than 2,000 CDs without difficulty. This computer has almost certainly burned over 6,000 CDs in its lifetime, with no problem at all so far. (We can't economically mass-produce the CDs because the ones we ship to distributors contain different content, depending on the distributor and their target market.)

I've been bugging the money people to get a CD duplicator machine, but the CD burner in my laptop has been extemely reliable.
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#11955 - 09/23/10 08:36 AM Re: re: adapters and batteries [Re: kevs]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: kevs
the thin part of the cord wraps around those cord ears no? that's what it's there for no?


It's there to ruin your cord. wink In theory it's a good idea for stowing the cord and the pack, but #1 it makes the pack thicker which in my experience fits worse in a bag than it should, and #2 like any wire or coat hanger, if you bend it back and forth in the same exact place repeatedly you will cause metal fatigue and break the wire. Winding the cord around the sharp turns at the ears repeatedly in the same exact place is just asking for cord damage.

I have taken apart one of those cables that was damaged that way, and when I peeled off the white jacket, an area about 3/4" long at the bend where there should have been a continuous braid of wire, there was wire bits about 1mm long each, that fell onto the table like sand, leaving an exposed white insulator around the core wire, with no outer wire for almost an inch. The white insulator (plastic) was severely cracked at that same location. In this case the wire had become intermittent, having to be bent carefully to start charge. In other cases I've seen, the white insulator was breached at a crack, allowing bits of shredded shield cable to get in and touch the center conductor, causing a short, and either leading to sparks (rarely), or melted outer plastic jacket. (numerous examples) Thankfully no fires, but it was certainly a possibility. The new magsafes are much better protected against this because the white pack will stop sending power if it detects a short.

I never use my pack's ears. The pack in my bag I stow by carefully looping the long cord in about a 5" circle, finishing by folding the pack down into the middle of the loop and slip that into the bag. In this way the pack also doesn't get any thicker so it doesn't bulge out my bag quite so much. It goes in there beside a 2.5" lacie service drive and an airport express, which are all the same thickness, so there's no bulge at all in my bag on that side.

Originally Posted By: kevs
How much time do you get on a batter?

varies wildly on my use. when I know I'm going to be pushing it I'll turn my display intensity as far down as I can tolerate, make sure my computer is set to sleep the display, and sleep the computer after a short time. (5 min) A lot of the time I have to get my computer out for service, I'm only needing my computer for brief periods of time over what may be hours of work, so the computer gets to go to sleep or sleep the display a lot so battery life can effectively be 8 or more hours. But if I'm actively using it, like to say watch videos to kill time while waiting for a car repair, I can expect 1.5-2 hrs per battery. So it's very dependent on your use.
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#11965 - 09/23/10 01:33 PM Re: re: adapters and batteries [Re: Virtual1]
kevs Offline


Registered: 12/07/09
V
thanks,
well the part of the cord that wrap around those ears are the thin cord no?
Still maybe you are right, just don't wrap it around that block/ ears.

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#11976 - 09/24/10 08:15 AM Re: re: adapters and batteries [Re: kevs]
alternaut Offline

Moderator

Registered: 08/04/09
This MacWorld review contains information relevant to your question about battery vs. external power use.
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#11977 - 09/24/10 09:17 AM Re: re: adapters and batteries [Re: kevs]
Virtual1 Offline


Registered: 08/04/09
Loc: Iowa
Originally Posted By: kevs
V
thanks,
well the part of the cord that wrap around those ears are the thin cord no?
Still maybe you are right, just don't wrap it around that block/ ears.


I just loosely coil it around the outside perimiter of the square profile of the adapter.
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#12033 - 09/27/10 03:53 PM Re: re: adapters and batteries [Re: kevs]
dianne Offline

Moderator

Registered: 08/04/09
In the interest of providing MikeS with a separate topic for troubleshooting his specific hardware question, a branch of posts has been detached from this thread and renamed. It can be found at PowerBook battery question.
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