13 Replies Latest reply: Jan 29, 2007 9:15 AM by Kappy
sebastian cheng Level 1 Level 1 (115 points)
I preferred getting imac than macbook simply because I do not need to worry about battery losing its life span. I currently own a G4 powerbook and I have 2 batteries: one new, the other useless. Say if I want to get a macbook, can I operate it directly from power outlet without it's battery attached? In that case, I will not be worried about overcharging the battery with the power outlet attached.

Thanks.

PB G4, Mac OS X (10.3.9)
  • Victor Chavarria Level 1 Level 1 (120 points)
    Hi, welcome to Apple Discussions.

    You will indeed be able to use the MacBook without the battery attached as long the power cord is plugged in. I don`t know if thats a good idea since MacBooks have the MagSafe power adapter that will come right off if any sudden force is applied ( to save computer from potential fall from people or other stuff tripping on your power cord). So if your using it without battery and by any reason something applies force to your power cord it will yank off and in that case ( battery unplugged) shutting down instantly the computer without saving any work or any changes done.
    And also I guess that you can prevent overcharging by just don`t charging it for to much time ( i.e if your battery is charged unplug the power cord and drain it) also you don`t have to let your computer charging overnight and since you are carrying the power brick ( for using w/out battery) you don`t need for it to be at 100%.

    Hope it helps.

    -Victor
  • Kappy Level 10 Level 10 (244,905 points)
    You can run the MacBook without the battery but if you do the CPU will automatically throttle down to a slower speed. If that's not a problem then you can leave the battery out. Apple does not advise doing this. Furthermore there is little point to it. You cannot overcharge the battery. The charging circuitry shuts off charging once the battery is re-charged until the charge level declines below 95 percent. A fully charged battery cannot overcharge.

    Lithium-Polymer batteries do not lose charge capacity as do the older technology batteries used in your Powerbook. The MacBook battery has an average life of 500 full discharge/recharge cycles. Partially discharging and then recharging the battery will not shorten its life. Read the following:

    http://www.apple.com/batteries/
    http://docs.info.apple.com/article.html?artnum=86284



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  • poisongirl Level 1 Level 1 (100 points)
    To add to what Kappy said, it will not harm your laptop to leave the AC Adapter plugged in at all times, and it will be a good backup (in case of power failure etc) to have your battery in place as well. This is what I do with both my MacBook and Dell XPS m140.

    I will periodically un-attach the AC Adapter and use the laptop with the battery alone, or even just let it stay in sleep mode while I am not using it and let the battery slowly drain away. Then when it gets down to a low percent of power (10-20 % maybe), then I will plug the AC back in and let it charge up again.

    I do this once a week or so, just to keep the battery's power moving out and new power in, and I might re-calibrate (spelling?) the battery once every couple months to help keep the battery "knowing what it's full capacity is" and therefore keeping the battery life up to a more full capacity and for a longer lifespan...

    That's one of the benefits of using a laptop as a desktop replacement actually. You can move it around with it's small form factor and lighter weight, you can use it anywhere with the battery and having bluetooth and WiFi to use for Internet/accessories/PDA and Cellphone connections, and the battery can act like a built-in backup power supply unit (PSU) which is not just good for storms and other power outtages, but even if you just want to move the location of where you have your laptop (from one room to another) while it is turned on and doing stuff... You can go ahead and unplug that AC Adapter, move it and then plug it back in if you wish to do so, and during that time, your computer kept on doing it's thing (can your desktop do that?) with maybe the only effect being that (depending on your system settings), your screen's display might have dimmed for a couple minutes - if you have it set to dim to a lower brightness amount for battery power compared to AC Adapter power.

    Also, I have heard (like many others have) that if you never actually use your battery, that it will die quickly from not enough use, but if you are constantly recharging your battery, you can expect it to slowly lose what used to be it's full capacity (in the long run, should last 2-3 years anyways I would guess) but one would assume that only recharging your battery once a week or so and using AC power with it for the most part would extend the life of you battery (and if you don't like to use it alot, then it makes sense to not want to have to purchase a replacement battery after 2 years or so, just so you can have one available if/when needed).

    I can't say more specifically what the effect is to do this middle ground option, but as long as your battery gets a recharging a few times a month that will be enough to keep it holding power. My GameBoy Advance SP came with a little booklet saying that the internal rechargable battery it has inside (which cannot be replaced by the user) has so many charge cycles in it. Basically, that after so many cycles, the battery capacity will not be as much as it was brand new, and slowly over time the battery will not charge and store as much power inside it, and eventually after the estimated number of cycles (which was only the "guarantee" #) that it, the battery, could totally die and have lived it's full lifespan (compared to it being a bad defective battery). Cell phone batteries often act like this too, so one would assume that laptop batteries could as well.

    If a battery had say 400 or so recharge cycles in it (like the GBA SP), and you were using it everyday and needing to recharge it everyday or 2 in the beginning, after half a year you might need to charge it twice as often in the same amount of time, and let's say you use it a bit less often then for the next 6 months, that battery with 400 cycles could last possibly for only *1 Year or so* (if using it so much that you were constantly charging it). If you used it less often, say a couple times per month, and only needed to charge it once per month, then it could last you for up to 5-10 years easily. I'm sure there would be other factors to affect it all, but as a basic comparison, it shows that it could last MUCH longer with just simple basic use every now and then. To be honest, the # I came up with was actually more like 30 years, but I cut it down alot to try and allow for the craziness that a battery for a GBA SP could last 30 years with only a regular "once a month" use...
  • Kappy Level 10 Level 10 (244,905 points)
    I will periodically un-attach the AC Adapter and use the laptop with the battery alone, or even just let it stay in sleep mode while I am not using it and let the battery slowly drain away. Then when it gets down to a low percent of power (10-20 % maybe), then I will plug the AC back in and let it charge up again.

    I do this once a week or so, just to keep the battery's power moving out and new power in, and I might re-calibrate (spelling?) the battery once every couple months to help keep the battery "knowing what it's full capacity is" and therefore keeping the battery life up to a more full capacity and for a longer lifespan...


    This is not necessary. There is no point in discharging and recharging the battery more than once per month to re-calibrate if the battery is not in frequent use.

    "The battery has an internal microprocessor that provides an estimate of the amount of energy in the battery as it charges and discharges. The battery needs to be recalibrated from time to time to keep the onscreen battery time and percent display accurate. With all iBooks and PowerBook G4 computers except the aluminum PowerBook G4 (15-inch Double-Layer SD), you should perform this procedure when you first use your computer and then every few months thereafter." Quoted from KB article Number 86284.

    Also, I have heard (like many others have) that if you never actually use your battery, that it will die quickly from not enough use, but if you are constantly recharging your battery, you can expect it to slowly lose what used to be it's full capacity (in the long run, should last 2-3 years anyways I would guess) but one would assume that only recharging your battery once a week or so and using AC power with it for the most part would extend the life of you battery (and if you don't like to use it alot, then it makes sense to not want to have to purchase a replacement battery after 2 years or so, just so you can have one available if/when needed).

    I recommend a close read of this KB Article. A Lithium-Polymer battery has an expected life of 500 full discharge-recharge cycles. If the battery is going to be stored it should be discharged to about 40 percent of capacity before storage. This is the optimum charge level for long-term storage.

    Here's a good site to learn about batteries. This is a better source of information than hearsay. Battery University.
  • elmington Level 1 Level 1 (0 points)
    This topic has been discussed a lot. Generally, I agree it's important to use the battery a lot, but 1) not to always discharge it completely (apple, batteryuniverity) 2) use it often (same) 3) not to leave it plugged in at full charge all the time (batteryuniversity, people i know with completely dead Powerbook batteries that did this)

    What I do it take out the battery when I'm home, since i just put it in the corner, connect it to a monitor, and close the lid.

    Also, when I'm going to be sitting at a desk for a few hours, I also take the battery out.

    I still use the battery every day, but I don't like leaving it fully charged and connected to the power all the time.
  • Kappy Level 10 Level 10 (244,905 points)
    Well, if you run the computer without the battery the CPU will throttle back to half speed. You may notice the computer is a bit slower without the battery.

    The battery cannot overcharge. The charging circuitry shuts off automatically when the battery is fully charged and does not activate until the charge level drops below 95 percent. Leaving the battery installed when fully charged will not adversely affect the battery and will allow the computer to run at its full speed.

    The batteries used in Powerbooks are a different technology than the Lithium-Polymer batteries.

    True this topic has been discussed a lot, but there still seems to be an awful lot of misinformation.
  • poisongirl Level 1 Level 1 (100 points)
    I agree that there seems to be many differences in opinion on the topic, and I really appreciate the links you gave above, Kappy, as this is the info that we are really needing to see (and read, obviously). A collection of info on the different battery types as well as how you use your Batttery and AC Adapter (the different methods one might use if constantly using AC with Battery installed, Using AC half the time and Battery the other half, or mostly just using the battery itself) as that would affect the daily/weekly/monthly/etc routines best used for the particular battery type.

    Is there a site that has all of this (the Battery University)? I have not yet had a chance to check out the links you gave in detail, but if this site does have most of that info, then I will just start to refer people to that site for this issue. If it doesn't, are there any others out there that people have come across? Maybe someone has enough info on different battery types and all that and could create a small little website even?
  • Kappy Level 10 Level 10 (244,905 points)
    Battery University is a good starting point. For more you can Google search but there are hundreds, thousands of sites to comb through in order to find useful information. BU provides a pretty good if not complete discussion of issues and concepts about batteries. But don't ask a question. You won't get any answers, leastwise I never have.
  • poisongirl Level 1 Level 1 (100 points)
    Heh. Alright, thanks.
  • elmington Level 1 Level 1 (0 points)
    HI Kappy. Indeed the CPU is throttled down to 1.0 Ghz, but sometimes I notice it's back up to 2. I haven't figured out the pattern. And running at 1.0 Ghz is not noticable for simple internet browsing. As an advantage, the machine runs cooler, and in fact I'd like to be able to throttle it manually.

    The biggest downside to running without a battery is that if the machine is awake and gets disconncted, it shuts down and you lose all work. Interestingly, if it's asleep and it gets disconnected, it wakes from deep sleep (takes a bit longer).

    Also, from here:

    http://www.apple.com/batteries/notebooks.html

    "Apple does not recommend leaving your portable plugged in all the time."

    You should definitely use the battery often.
  • Kappy Level 10 Level 10 (244,905 points)
    "Apple does not recommend leaving your portable plugged in all the time."

    You should definitely use the battery often.


    Read a few lines further down, "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."

    It is definitely not a requirement to always use the battery or not to stay plugged in to the AC adapter. Discharging and recharging every few months (as recommended for calibration) not only re-calibrates the battery but also forces the battery through a full charge cycle periodically. LiP batteries have an expected life of 500 full charge cycles. If you run down the battery once per day with an overnight recharge you can expect to replace the battery after 1.5 years or so. If you rarely use the battery and go through a charge cycle once per month then the battery could last 40 years (although I doubt that's likely.)

    If you would like to learn more about batteries including Li-Ion and Li-Polymer batteries visit http://www.batteryuniversity.com/.
  • Supermodified Level 1 Level 1 (0 points)
    Well, if you run the computer without the battery the
    CPU will throttle back to half speed.


    Interesting, I didn't know that. Any idea why it's implemented this way?
  • Kappy Level 10 Level 10 (244,905 points)
    Perhaps to reduce the drain on the AC adapter, but I really don't know specifically why that's the case.