what is the secret to good battery health?

bchamorro

macrumors regular
Original poster
Dec 31, 2007
160
0
I've heard it is bad to let it discharge completely. What is the secret to good battery health?
 

MrCheeto

macrumors 68030
Nov 2, 2008
2,966
0
The secret is, use it or lose it.

You have to put some sort of load on the battery and then charge it back up to keep it in good condition.

Leaving your computer plugged in for eternity will just let the battery waste away.

Ni-Cd batteries have what's called "voltage depression", meaning they lose capacity the more you use them. We use Lithium batteries these days, which don't have this effect, however, like all batteries, need to be charged and discharged to remain healthy.

At least once a month, drain the battery completely and recharge it. I have heard of people using their original iBook batteries from about 2000 with about 30 minutes to an hour of use at best, and those were Lithium-Ion, an old cell composition.
 

Alvi

macrumors 65816
Oct 31, 2008
1,202
307
Mars
Don't have it plugged in all day, after that plug it out 30 mins, plug it back in, after some hours again and so on, if you plug out your computer drain it, especially if you rarely do that, while travelling turn the backlit level as low as you can and turn of automated sensor features which use more battery, sometimes it can give you more than what apple claims, especially if you're just writing text on a plane or something like that

The main thing is being ok with it, accepting that it will perform worse in 2 years and so on, The secret for any product satisfaction is enjoying it without having to be super careful with it, like having a super thick case on your iPhone and so on, use the battery as it's comfortable for you as long as it lasts, then replace it, they're not that expansive for the satisfaction it will give you, sorry for offtopicing btw
 

Batt

macrumors 65816
Dec 17, 2007
1,234
4
Syracuse, NY
I leave mine plugged in 99.9% of the time. Once in a blue moon I decide to let the battery drain. I've done this maybe 4 times in 2½ years, and the battery still shows a 99% charge and still shows up healthy in System Profiler.
There is no standard answer, it all depends on how you use your laptop.
 

bsizz234

macrumors member
Jan 25, 2010
45
0
I leave mine plugged in 99.9% of the time. Once in a blue moon I decide to let the battery drain. I've done this maybe 4 times in 2½ years, and the battery still shows a 99% charge and still shows up healthy in System Profiler.
There is no standard answer, it all depends on how you use your laptop.
mine shows a 100% charge when it's done charging. problem is that now 100% is only 48% of what it used to be.

time for a new battery for the second half of the computer's life...
 

dehory

macrumors regular
Sep 17, 2008
208
2
At least once a month, drain the battery completely and recharge it.
Don't have it plugged in all day, after that plug it out 30 mins, plug it back in, after some hours again and so on, if you plug out your computer drain it...
Both of these points are incorrect.

The most well-reasoned and definitive response to this question that I've seen is from iLounge. Obviously what applies for a 2008 iPod battery applies for the newer generations of Apple portable computers.

There are a number of misunderstandings about how rechargeable batteries work in most modern electronic devices, most likely caused by some significant advances in battery technology over the years.

The first and most important consideration is that the majority of modern electronic devices with rechargeable batteries now use “Lithium Ion” batteries (Li-ion). Unlike earlier generations of rechargeable batteries which were based on Nickel Cadmium (NiCad) or Nickel Metal Hydride (NiMH), Lithium Ion batteries do not suffer from the “memory effect” when it comes to recharging. Previous Nickel-based rechargeable batteries, particularly NiCad batteries, would lose their maximum charge capacity if they were not fully discharged prior to charging them up.

Li-ion batteries, on the other hand, actually prefer to be topped up, and should never be completely discharged, as this will actually destroy the battery. Most electronic devices, including the iPod, have a cut-off circuit that turns the device off when the battery drops critically low in order to prevent this from happening, thereby leaving a small charge in the battery, so this is rarely a practical concern for an end user.

Likewise, while lithium-ion batteries can technically experience problems from overcharging (continuing to charge the device after the battery is fully charged), any properly-designed electronic device will incorporate a “cut-off” circuit to stop charging the battery once it’s reached its full charge level in order to prevent this.

Another point to note is that there is no requirement for a lithium-ion battery to be “primed” before use. Recommendations that a new iPod be plugged in and charged overnight before using it for the first-time are based on older nickel-based battery technology. For a Li-ion battery, there is no difference between the first charge, the tenth charge, or the 100th charge.

The life expectancy of a lithium ion battery in terms of how many charges it will take is measured in “charge cycles” which refers to the number of complete discharge and recharge cycles, not simply to the number of times the battery is “topped up.” Therefore, if you drain your battery by 25% and recharge it fully four times, this will count as a single charge cycle. Again, there is rarely a reason for the average iPod user to be worry about watching the charge level or being concerned about reaching a certain level before recharging—simply dropping the iPod into the charger whenever necessary is fine.

In fact, the only reason in the case of an iPod for doing a complete discharge and recharge of an iPod is to re-calibrate the battery meter itself (ie, the iPod’s display of how much power is remaining). This has no impact on the actual battery life, but will help the iPod provide a better estimation of the remaining life for the user by ensuring the battery gauge is accurate.

In terms of how the charging process itself works, Li-ion batteries charge in two stages: If the battery is below approximately 70-75% charge level, the fist stage involves applying full charging power to get the battery charge up to that level. Once the battery reaches the 70-75% level, a “topping” charge is applied, whereby the current to the battery is gradually decreased as the battery capacity reaches 100%. This is done in order to avoid overcharging, and is sometimes referred to as a “trickle” charge, although this is technically incorrect by definition, since a “trickle charge” refers to continuous power being applied to a battery once it has reached full charge, which Li-ion batteries do not do, again in order to avoid the risk of overcharging.

With a Li-ion battery, once full charge has been reached, the charging circuit will shut off completely and stop providing any charge to the battery. At this point, as long as the device remains connected to external power, the battery goes dormant and the device simply runs from the external power source. What this means for the iPod is that as soon as you see the “Plug” icon on the battery indicator, charging power has been cut-off and the device is simply running from the external power source.

If you leave the iPod connected to an external power source for long enough, the battery will drop slightly in power just from normal energy loss (in the same way that it would if it were simply sitting on a shelf turned off). Once the battery falls below a certain level, a topping charge will be reapplied to bring it back to full, but this normally happens very infrequently as long as the device remains connected to external power—possibly as rarely as only once every three to four weeks.

Disconnecting the iPod from external power and reconnecting it will re-initiate the charge circuit, since the battery level needs to be re-checked, and a small topping charge may need to be applied to get back to 100%, but unless the device has been used on battery, the iPod should return to the plug icon within a few minutes, once again indicating that the battery is fully charged and the device is running from AC power. In many cases no topping charge is applied, and this delay is just the time it takes for the iPod to resolve that the battery is, in fact, fully charged.

The net effect of disconnecting and reconnecting your iPod from its dock should be basically neutral in terms of battery life. The topping charge is applied only to bring the battery back to 100%, so this is a fraction of a battery cycle in the same way as any other charge.

Unfortunately, many of the now-outdated issues with nickel-based batteries have become urban myths for modern electronic devices, and can cause many iPod owners much completely unwarranted angst about their device and their battery life. In reality it is almost never necessary for a typical iPod user to worry much about the iPod battery… The simple rule of thumb is to use the device as you normally would, charge it when it needs it, and don’t worry too much about leaving it on the charger for reasonable periods of time.

In fact, just about the only issue to be aware of is for those rare users who use their iPod from external power all the time. In this case, since the Li-ion battery is not being used (the device is running from external power), the battery itself doesn’t get properly “exercised” and this can decrease the battery life over time. This is only an issue for users who almost never run their iPod from the battery. Apple’s own support site simply suggests that the battery be put through at least one complete charge cycle per month. Considering that even twenty 5% “top-up” charges still counts as a charge cycle, the reality is that for the vast majority of iPod users, normal everyday use will easily take care of this.
 

m85476585

macrumors 65816
Feb 26, 2008
1,222
4
But most people aren't leaving their ipods plugged in 24/7.

Storing a battery at 100% charge is bad for it, and is essentially the same as leaving it plugged in 24/7.
As you can see in the first table on this page
http://www.batteryuniversity.com/parttwo-34.htm
A battery stored at 100% charge and 40C may drop to 65% health after a year, as opposed to 85% for one stored at 40%. A battery in a laptop will do better than that since it gets used at least a tiny bit, but the point it leaving the battery at 100% all the time is bad for it. Discharging and recharging the battery, at least partially, refreshes the chemicals inside and prevent the health from dropping.

In short:
-Using the battery regularly is good
-Try to keep the computer cool. Don't run it on a blanket, and don't leave it on 24/7 if you aren't using it.
-A full discharge until the computer shuts off is not necessary except to calibrate the battery life meter.
-Don't worry about the battery and it will probably be OK.
 

applesupergeek

macrumors 6502a
Nov 20, 2009
879
0
Wait a sec guys, surely if you use your battery more frequently than others, that will decrease it's life cycle. So you might need to occasionally unplug your mac, but I don't know if you mostly unplug it and let the battery drain to a certain point if you are helping anything, apple has made it clearly there are certain finite charge and discharge cycles.
 

m85476585

macrumors 65816
Feb 26, 2008
1,222
4
If you have one that is rated to last 1000 cycles, it will last 3.8 years if you use 1 cycle per weekday.

I leave my laptop plugged in most of the time, and I'm already on my third battery (mine is older and the batteries are rated for 300 cycles). Both batteries had right around 100 cycles on them when they were replaced, and they were both a bit less than 80% health (the point at which Apple will replace it). Using the battery will decrease the life, but that doesn't mean not using it won't decrease the life (triple negative). Basically, batteries have a finite life no matter what. If you don't use it, you will shorten the life, and if you use it excessively (multiple cycles per day), you will also shorten the life. Moderate use seems to be best.

With this battery I've started keeping it cooler and using the battery more. I run SMCFanControl at 3K RPM all the time, I have an aluminum cooling pad that keeps the CPU 10C cooler, and I put the computer to sleep at night instead of leaving it on 24/7. I am trying to intentionally use it on battery more, but I still don't do that much because I am forgetful.
 

ARF900

macrumors 65816
Oct 30, 2009
1,119
0
The secret is to just use it however you want, however if you are going to leave it plugged in 24/7 Apple does recommend you calibrate the battery once a month to keep it in good health for that time when you really do need it.

But why buy a notebook just to leave it on a desk all the time?
 

SDub90

macrumors 6502a
Nov 9, 2009
685
3
Long Island
I completely discharge my macbook once a month at least, typically keep it plugged in all the time when I'm using it if I can and unplug it if it's at 100% when i put it to sleep. If I'm storing for over a few days without expected use (ie I go away and leave it home) I drain it to roughly 70% and leave it sleeping and unplugged.

You want to avoid:
-Going through an excessive amount of full cycles
-Frequent short discharged (charging to 100%, discharging to some lower % like 30, 50 or 80, then charging to 100% and repeating)
-Keeping it fully charged all the time
-Only using the battery for short periods of time

My first macbook battery lasted 2 3/4 years and lasted 4 hours before I started to go through several cycles a day for 6 months, after those 6 months it went down to 2 1/2 - 3 hours. Had the battery replaced and a year later I still get 4-4 1/2 hours depending on my usage.
 

w00t951

macrumors 68000
Jan 6, 2009
1,831
4
Pittsburgh, PA
Trust me: 15 laptops of experience.
The new lithium batteries don't require a full discharge to remain healthy. If you take enough time and peruse the Apple article it says that the purpose of cycling the battery is to make sure that the battery percentage indicator is accurate. By completely cycling the battery you take one charge cycle. Around 1,000 charge cycles, your battery capacity will be greatly diminished. The secret that I've found to keeping your battery healthy is to try and keep down the number of cycles. One cycle is about 50-100 percent of the battery's capacity.
 

kbt1020

macrumors regular
Feb 15, 2010
138
1
So usually, is it good to shut down the mbp? sleep w/ it plugged in or unplugged?
 

m85476585

macrumors 65816
Feb 26, 2008
1,222
4
Shutting it down/sleeping keeps it cooler, which can't hurt the battery. I don't think it really matters much if the cable is plugged in or not while it is asleep.
 

Saturn1217

macrumors 6502a
Apr 28, 2008
973
232
Ugh I hate reading these battery care threads. I always end up more confused than when I started.

You want to avoid:
-Going through an excessive amount of full cycles
-Frequent short discharged (charging to 100%, discharging to some lower % like 30, 50 or 80, then charging to 100% and repeating)
-Keeping it fully charged all the time
-Only using the battery for short periods of time
I don't mean to be rude but in your list of what to avoid you basically just list all the possible ways I can think of to use (or not use) the battery. If this is what you shouldn't do then what are you supposed to do?!

I only ask because my battery capacity (as measured by system profiler) seems to go down every time I use it. At first I tried only partial discharges but that was not so good and now I'm trying longer discharges but it's still dropping more than I'd like. I definitely don't feel like I'm getting the benefits of the built in battery on the new uMBPs :(
 

ammusk

macrumors regular
Oct 20, 2009
122
0
Ugh I hate reading these battery care threads. I always end up more confused than when I started.



I don't mean to be rude but in your list of what to avoid you basically just list all the possible ways I can think of to use (or not use) the battery. If this is what you shouldn't do then what are you supposed to do?!

I only ask because my battery capacity (as measured by system profiler) seems to go down every time I use it. At first I tried only partial discharges but that was not so good and now I'm trying longer discharges but it's still dropping more than I'd like. I definitely don't feel like I'm getting the benefits of the built in battery on the new uMBPs :(
Discharging it partially hurts. Always try to do a full discharge and consequent full recharge.
 

MacGiver

macrumors 6502a
Aug 12, 2007
627
29
France
Sharing my experience here. I bought a MBP end of 2007. I most of the time use it at home and left the MBP plugged on the mains...result is that after a short time the battery died after 10min whenever i used it unplugged.
My wife left did the opposite with her black MB...result...the battery is still in very good health!

Conclusion: never ever leave your laptop on the mains all day long! My laptop simply became a desktop...lesson learned for me as i plan to buy the incoming 13" MBP and sell my old one (of course with a brand new battery)
X
 

jjahshik32

macrumors 603
Sep 4, 2006
5,259
1
My routine involves in leaving the mbp plugged in at all times at home and only use the battery when out and about.
 

jjahshik32

macrumors 603
Sep 4, 2006
5,259
1
Sharing my experience here. I bought a MBP end of 2007. I most of the time use it at home and left the MBP plugged on the mains...result is that after a short time the battery died after 10min whenever i used it unplugged.
My wife left did the opposite with her black MB...result...the battery is still in very good health!

Conclusion: never ever leave your laptop on the mains all day long! My laptop simply became a desktop...lesson learned for me as i plan to buy the incoming 13" MBP and sell my old one (of course with a brand new battery)
X
I honestly believe that it was a special case for your 2007 mbp. Iv actually heard the opposite that keeping the mbp plugged in is better than to continuously uncharging and charging the battery.

I know that once in a while it is good to completely discharge the battery and fully recharge.
 

SDub90

macrumors 6502a
Nov 9, 2009
685
3
Long Island
Ugh I hate reading these battery care threads. I always end up more confused than when I started.



I don't mean to be rude but in your list of what to avoid you basically just list all the possible ways I can think of to use (or not use) the battery. If this is what you shouldn't do then what are you supposed to do?!

I only ask because my battery capacity (as measured by system profiler) seems to go down every time I use it. At first I tried only partial discharges but that was not so good and now I'm trying longer discharges but it's still dropping more than I'd like. I definitely don't feel like I'm getting the benefits of the built in battery on the new uMBPs :(
Doing the things in that list frequently will drastically shorten battery life. Everything you do with the battery will shorten its life in some way - some greater than others. My day is pretty routine and I'm always near a power outlet, so it's very easy for me to find the right balance of battery usage to have it hold its charge much longer than most people, but the techniques I use nearly defeat the purpose of having a laptop.

The most important things are to have at least 1 full discharge each month and to not unplug the charger and drain the battery as soon as it hits 100%.
 

Gomff

macrumors 6502a
Sep 17, 2009
802
1
Part of it is luck of the draw.

I have a late 2006 Macbook pro. Apple replaced the battery on it about a year and a bit ago, after I complained that it had only had 46 loadcycles and was running below 80% efficiency. The one I have now is much healthier - 57 loadcycles and 93% efficiency according to Coconut battery. When I got the battery it was 98% so it hasn't dropped too much.

Usage wise, it's plugged in at my desk most of the time but I usually bring it to the front room to surf in front of the TV a few times a month in the evening, so it gets some usage. I can get about 3 hours out of it surfing, with the screen dimmed to about 40%.

Conversely, a buddy of mine has a 3 year old Macbook - his battery has about 180 loadcycles and still reads 91% efficiency. He uses it just on battery power a lot and maybe that has something to do with it's great performance. Equally my 2G iPhone will regularly run for 5 days in between charges and seems to show no evidence of wear and tear in the 2 and a half years I've had it.....I think I got lucky with that battery though.

I still think it's a combination of reasonable usage and getting a lucky break.
 

Dan73

macrumors 6502a
Jul 30, 2009
506
0
I leave mine plugged in 99.9% of the time. Once in a blue moon I decide to let the battery drain. I've done this maybe 4 times in 2½ years, and the battery still shows a 99% charge and still shows up healthy in System Profiler.
There is no standard answer, it all depends on how you use your laptop.
Use the battery for a few days and report back then
 

mrsir2009

macrumors 604
Sep 17, 2009
7,501
156
Melbourne, Australia
When I'm using my MBP I never have it on the charger. I use it for quite long periods, and when I'm finished with it there is usually about 20-40% battery left. When I'm not using it its on the charger, so when I go to use it its full (or almost full). This method ensures the MBP gets nice deep battery cycles:D