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You are here: MacNN Forums > Hardware - Troubleshooting and Discussion > Mac Notebooks > Stop MacBook From Charging?

Stop MacBook From Charging?
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Hg2491
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Jul 21, 2008, 09:42 PM
 
I know it's an awkward question, but how can I stop my MacBook from charging?

I would like to have the battery in lets say 50%, connect it to the wall plug and have the MacBook only consume the power necessary to run.

Thanks in advanced,
Hg+
     
REVBCO
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Jul 21, 2008, 10:21 PM
 
Why?

I don't think that you can do it without taking the battery out after you plug the macbook in.
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Hg2491  (op)
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Jul 21, 2008, 10:36 PM
 
Because here in Dominican Republic we don't have a steady electrical service. Everyday my house is out of city electricity for about 4-7 hours so we use an inverter to power it.

It would be great if I could run the MacBook on battery and when the juice is out, connect it to the wall and not have the battery charge. In this way the inverter would last for a longer period of time.
     
ginoledesma
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Jul 22, 2008, 01:04 AM
 
You could purchase a power strip timer. You can configure those to turn off certain outlets after a certain period of time. More expensive ones even allow you to schedule a time for the outlets to be on/off.
     
charlespsu
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Jul 22, 2008, 09:26 PM
 
I would suggest taking out the battery.....you don't want to do anything that makes the battery "learn" only 50%.
     
ibook_steve
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Jul 22, 2008, 10:04 PM
 
Wouldn't it make more sense to charge to 100% (which is best for the battery) and just disconnect AC when the power is out, running it off of the battery? I'm still not quite sure why you want to do it the way you mention.

Do you mean a "generator" instead of an "inverter"?

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Hg2491  (op)
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Jul 22, 2008, 10:55 PM
 
Steve, when the battery drains I will need to charge it again, taking energy from the inverter.

No, a generator works with gasoline, while an inverter acts as a big UPS.
     
Simon
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Jul 23, 2008, 02:29 AM
 
I think getting a timer is the only way to accomplish that. The only way to prevent battery charging is to take out the battery. And that is a really bad idea from a performance POV (reduces CPU clock and supposedly also shuts off one core).
     
OreoCookie
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Jul 23, 2008, 06:35 AM
 
The charger doesn't draw a lot of power, about 45-65 W at most. This is less than a standard light bulb (60-100 W) and a lot, lot less than something like a hair dryer or so (~1000-2000 W).

Are you convinced it makes much of a difference?
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ibook_steve
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Jul 23, 2008, 12:14 PM
 
Originally Posted by Hg2491 View Post
Steve, when the battery drains I will need to charge it again, taking energy from the inverter.

No, a generator works with gasoline, while an inverter acts as a big UPS.
Right. So charge it when the power comes back on.

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mduell
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Jul 23, 2008, 08:41 PM
 
Charging and discharging the battery isn't 100% efficient, so he'd be wasting power if he allowed the MacBook's battery to charge and then used it compared to just using the inverter he has. The easiest way to not charge the battery is to remove it, but Apple has decreed this should come with severe performance penalties for no apparent reason.

Originally Posted by charlespsu View Post
I would suggest taking out the battery.....you don't want to do anything that makes the battery "learn" only 50%.
Huh? Lithium batteries last longer (in terms of years) when maintained at around 50% capacity.
     
Hg2491  (op)
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Jul 23, 2008, 08:56 PM
 
@ OreoCookie
The charger itself doesn't but an empty battery does.

@ Steve
Then I wouldn't be able to use it while the lights are out.

@ mduell
The sole reason why I haven't considered taking the battery out is because I have a SeeThru.

Thanks for all the feed back,
     
ibook_steve
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Jul 23, 2008, 11:25 PM
 
Originally Posted by Hg2491 View Post
@ Steve
Then I wouldn't be able to use it while the lights are out.
Yes, you would. You'd be running off of the machine's battery. Am I missing something here?

Steve
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AKcrab
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Jul 23, 2008, 11:43 PM
 
Originally Posted by ibook_steve View Post
Am I missing something here?

Steve
If you are, you're not alone. Could it be that we have a different idea of what an inverter is?
     
Simon
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Jul 24, 2008, 02:59 AM
 
Originally Posted by Hg2491 View Post
The sole reason why I haven't considered taking the battery out is because I have a SeeThru
As I already mentioned, you wouldn't want to do that anyway. The performance decrease is substantial.
     
OreoCookie
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Jul 24, 2008, 06:13 AM
 
Originally Posted by Hg2491 View Post
@ OreoCookie
The charger itself doesn't but an empty battery does.
I don't get it, all the power to the MacBook (including its battery) is supplied by the charger.

The battery doesn't consume any power, if it is charged and the charger supplies all the power to the system. If the battery is not full, part of the power supplied by the power brick will be used to charge the battery, the rest is used to run the system. So of the maximum output of 65 W the current MacBook's power brick can supply, only a part of that is typically used to charge the battery (a MacBook consumes about 15 W if the system is idling, Bluetooth and WLAN are switched off and the brightness is set to minimum, but it tops out at 53 W or so). So under typical load, you might shave off 10, 20 W if you could stop your MacBook from charging.
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Hg2491  (op)
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Jul 24, 2008, 06:21 AM
 
Let me explain myself better:

The lights go off, I start using the MacBook on battery, the battery runs out. At that point I would be forced to use the house's batteries to charge the computer. I would like to connect the MacBook to the wall and NOT have the battery charge at that point; only use the house's batteries to run the MacBook.

Get it now? :S:S
     
OreoCookie
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Jul 24, 2008, 07:02 AM
 
I got that from your initial posts, that's why I'm telling you that this doesn't make much of a difference if you charge your batteries or not. But subsequent posts, though, have left a lot of people (including myself) confused.

In fact, turning down your screen brightness and stop using apps that are cpu-intensive is going to be equally or more effective than to stop charging your batteries. Or fully charging your battery when you have power (because then, the battery doesn't `consume' any extra power) and you can choose between running your computer off battery (drains no power whatsoever from your backup power source) or having it plugged in, but consuming a few Watts less (because it doesn't need to charge). Keeping it partially charged on purpose seems like the worst solution to the problem.
( Last edited by OreoCookie; Jul 24, 2008 at 09:11 AM. )
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ghporter
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Jul 24, 2008, 08:57 AM
 
Originally Posted by Hg2491 View Post
Let me explain myself better:

The lights go off, I start using the MacBook on battery, the battery runs out. At that point I would be forced to use the house's batteries to charge the computer. I would like to connect the MacBook to the wall and NOT have the battery charge at that point; only use the house's batteries to run the MacBook.

Get it now? :S:S
I get your issue too, which is why I am curious about why you only want your battery charged to 50%. That gets you a lot less operating time while the lights are out. Leaving the machine plugged in and with the battery installed until the lights go out, then just unplugging it, would give you a lot more time to use the computer before you exhaust he battery.

So I'm curious what it is that makes you want to keep it at only 50% in the first place. Is it because you think the computer will use that much more power from your inverter? Unfortunately, I don't know of a place I could find definitive data on the power draw of your computer's AC adapter, but there would not be much difference between how much power it takes when charging and how much it takes when simply performing CPU intensive tasks. In other words, I don't think you'd get much savings on the inverter drain by doing any of this stuff.

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Hg2491  (op)
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Jul 24, 2008, 08:51 PM
 
Thanks for the feedback guys.

I said 50% to put an example. My point was to keep the battery from charging.
As you guys have pointed out, it's not worth taking out the battery / keeping the battery from charging.

Thanks again,
Hg+
     
   
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