Pull the plug. Your battery will thank you | Hacker News Reader

Pull the plug. Your battery will thank you

thisweekinbatteries.blogspot.com

91 pointsdmlorenzetti49 comments

I've had Apple laptops going back to the release of the Titanium PowerBook and I've almost always used them plugged in for the vast majority of the time and I've never had this dreaded battery death that articles like this talk about.

However, I have a friend who seems especially apt at killing the very same batteries in the very same laptop models. My rather uninformed theory is that there's a specific kind of behavior that adversely affects them - but whatever it is, I don't do it and he does. I think the key is that he uses his without power a lot, running it down frequently, etc. which seems to be what this article is suggesting (and most articles about prolonging battery life suggest).

Given my own experience, I'm continuously confused at the pervasiveness of this advice given how counter it is to my own experience - but perhaps there's some intelligence in the batteries/charger that's protecting me from myself?

I mostly think of my battery as a built in UPS and not as a gas tank.

Right. So, don't run it down a lot, and don't charge it to 100% unless you have to.

FYI, Apple have a page providing advice on battery care:

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

One of the things it says is...

"Standard Maintenance

For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally. 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."

For proper maintenance of a lithium-based battery, it’s important to keep the electrons in it moving occasionally."

I knew I shouldn't have set my air conditioner to absolute zero...

I’m not an expert, but I heard in the past that the main reason for this was keeping the battery meter calibrated – so that it could accurately tell you how much battery remained, and how long it would take to drain – more than really for prolonging life.

As far as I know, the information here is still relevant: http://www.macosxhints.com/article.php?story=200303140818432...

In short:

> There is no memory and no scheduled cycling is required to prolong the battery's life.

> The typical life span of a Li-ion battery is two to three years, whether it is used or not.

> The internal resistance of the Li-ion batteries cannot be improved with cycling. The cell oxidation, which causes high resistance, is non-reversible. The electrolyte slowly eats up the positive plate and the electrolyte decays. This chemical change causes the internal resistance to increase. In time, the cell resistance raises to a point where the battery can no longer deliver the energy.

I bought a replacement battery for my 2006 Macbook Pro and it started acting funny after about 6 months (the original lasted a while and had run its course). Went to the Apple Store, they did a diagnosis test on it, determined it was bad, and handed me a free replacement.

4 months later the replacement started having issues too. They tested it, found it was bad, and gave me another free replacement. That one's going on 8 months strong without issues.

I asked the tech why this was happening, if it was an issue with my laptop or something. He said that sometimes batteries go bad. It's the nature of the beast.

My current (2007?) MacBook Pro laptop battery dies in the arse at 78% if I leave it disconnected. I always leave it connected so I guess that goes to show. My previous iBook G4 battery also had some problems, but it died closer to 20%.

I have a Lenovo laptop and it has the feature it describes. You can set a manual charge cut off or do the following:

"Optimize battery lifespan (automatically change for me)"

Right now, it seems to not charge the battery unless it gets under 96% charge, and then it charges to full. Its language implies that it changes that charge level based off of a good compromise between battery life and charge. As someone who doesn't want to think about the battery issue, I really love this feature.

Macbooks do the same, but I haven't found a way to change the threshold. 90, 85 or even 80% would be fine for me.

So, why don't laptops completely bypass the battery when the battery is charged and the power is plugged in? If the laptop can work when the batteries are removed, it should be able to cut-off power to/from the battery when fully charged as well.

When the laptop is at home, just charge the battery to 50% then remove it so it works only from the plug. I don't move my laptop as much as I did before and I noticed that I get much better battery lives than my friends who continuously keep their laptop plugged in and with the battery attached.

Obviously this is the current solution. I was pointing out that laptop manufacturers could remove the need for fiddling with your power connection by automatically disconnecting the computer from the battery when it is not needed.

Yes, but you need a way to tell it whether you don't want to use the battery in a long time (so 50% charge is good), or whether you want to get up and go on the road soon --- where 100% charging is nice.

Allegedly Thinkpads have that. But I run Ubuntu on mine so I don't have access to the fancy bios setting utilities from Lenovo. I just snap the battery out. That seems to work for me.

While correct, I really view this as a non-issue.

I suspect for most people, their in-memory data, time, and attention are far more valuable than not having power redundancy protection against an accidental cord disconnect or possible increased degradation on a ~$100 replaceable component on a $1k+ machine--namely the battery.

Huh... that's annoying. 95% of the time, I use the laptop in my home office and don't really want to mess around with plugging/unplugging it:-/

What about running it through a 6 outlet switch that you can readily turn on/off?

The problem is that I shouldn't have to do anything. The computer should be able to figure this stuff on its own - after all, that's the kind of task that they're good for.

Oh, the "computer" (read: the manufacturer) has it all figured out already, rest assured. They just don't want to give up on a few performance percentage points.

Or, more likely, selling you replacement batteries.

Ok, but at the same time, they could also tack some money on to the price for "batter life extending technology" and make money that way...

For desk use, it's best for your battery to remove it from the laptop once it's fully charged. You don't want to continuously plug/unplug your laptop because that would just cycle the battery a lot, and that's not good for it either.

As for me, I usually just leave the battery in: it's a nice UPS, worth the expense of perhaps a few months of lost life.

Do you know if one can hot swap batteries (which would also allow simply removing or adding it) on most laptops that will run without a battery? I want to try removing the battery from my computer while it's running or putting one in while it's running, but I'm a little afraid of death.

I've never had problems hot-swapping batteries on my laptops while they're plugged in, at least with my Gateway.

If you're laptop is plugged in you should be able to hot swap the battery. If you're worried about data loss, put your machine to sleep first, wait ~10 seconds, swap the batteries, wake it up from sleep. This is safe even if your machine loses power totally while swapping out the batteries.

OSX and Windows both support writing out your ram to disk, losing all power, then resuming from this state exactly where you left off when power is restored.

It's the default on OSX and may need to be enabled on Windows depending on your hardware: http://maximumpcguides.com/windows-7/turn-hybrid-sleep-on-in...

Yeah, I've done it after hibernating, but hibernating and waking up from it is like a 3-minute process for me.

It's not data loss I'm afraid of (I always save, even moreseo if I'm doing stuff that might make my computer turn off), it's like sparks and other such stuff that can happen when you're dealing with electricity.

I hot swap all the time, even if the computer is plugged in there should be no problem with sparks or anything like that.

Same here. Almost never unplug unless I need it for a meeting or am traveling. Seems to be fine after almost 2 years. Good enough for me.

Where I stay in Bangalore, we have about 3 one hour power cuts per day. So my laptop battery is getting good exercise!

The article mentions that Thinkpads come with a utility to set the charging cutoff point. Has anybody figured out how to do this on Linux?

http://www.thinkwiki.org/wiki/Tp_smapi#Battery_charge_contro...

bug filed - https://bugs.launchpad.net/ubuntu/+source/gnome-power-manage...

The article is right, but it's hard to read. If you don't read carefully, it seems to suggest cycling your battery more, when actually it just suggests not pushing it near 100% charge too long.

Here's a complete and simple summary of good practice: http://batteryuniversity.com/partone-21.htm (more details on other parts of that website) - for most geek-apparel, the LiIon column will be applicable.

I've had my MacBook for 1.5 years now, and my battery life is still a little more than 4 hours. I keep my machine plugged in all the time, and completely run it down once a month. On the other hand, my friends who have the same MacBook have terrible battery lives. They use the laptop on batteries all the time.

I'm inclined to believe this guy has no idea what he's talking about.

simpler solution than constant plugging and replugging for me was to remove the battery if I'm not going to be moving the laptop for an extended period.

It's nice having that battery as a UPS though, in the event of an outage.

I always knew you shouldn't leave your laptop plugged in all the time, but I never really knew why, and my subtle misunderstanding was actually harmful. I thought the issue was just that sometimes you needed to let the battery drain and recharge it from a drained state. That's not very helpful though if the rest of the time you're running at full voltage. Thank you for the submission. Great article.

Over the past four weeks my Macbook Pro battery's performance declined precipitously, and I think this is the cause. I tended to leave it plugged in whenever I was at my desk, which is most of the time. Got to the point where the MBP wouldn't last more than 5 minutes unplugged. Just received a new battery and all is well. Think I'll be giving this technique a shot.

Seems like it would be easy for laptop makers to design something into the laptop to manage how the battery charges/discharges when it's plugged in. That way you could leave it plugged in 99% of the time (as probably many of us do) and not impact the battery negatively.

Interesting... sounds like an interesting application for this idea:

http://www.unplggd.com/unplggd/green-ideas/leech-plug-unplug...

Newer Sony laptops come with "Battery Care" software that automatically keeps the battery between 50 and 80% at all times. According to Sony engineers, a battery that is always kept at or below 50% will essentially never degrade in capacity.

so what's the point of having a big battery then if it never charges to 100%?

Well, it's still more battery life than a small battery that never charges to 100%, right? I think regardless of the battery size, you can make the decision to preserve the long-term life of your battery or have the extra capacity in the short-term.

Plus, charging from 20 to 80% is much faster than charging from 20 to 100% (I estimate that about half of the time is spent just going from 80 to 100).

I killed 2 macbook pro batteries in 2 years by not following this advice. Now I make sure to unplug and carrying around the laptop whenever I can. Eliminating all wired peripherals was a key step to actually doing this in practise.

I thought the MBP battery switched off charging when it was full, so that it charges up the battery and then disconnects it if you are plugged in. When the battery has self-discharged some amount, it tops it up again. But maybe I misunderstood.

The flipside, though, is that Li-ion batteries also age from discharge cycles. So I really don't think it's better to run the battery down, charge it up, and repeat. The number of charge cycles is limited, so I bet that will kill it faster. If you really want to save the battery, you can take it out and put it in the fridge when you are plugged in.

> If you really want to save the battery, you can take it out and put it in the fridge when you are plugged in.

Unfortunately MacBook Pro batteries are not removable anymore. That really grinds my gears.

Well, technically you can and it doesn't look too hard: http://www.youtube.com/watch?v=42qcvlftmcM

But it seems apple is not officially selling those batteries, which makes my gears grind. I don't want to walk to an apple store or send my laptop away just to have the batter swapped.

Yes, you are correct: http://support.apple.com/kb/TS1909

At least, that is the way it is supposed to work. I've been through a few batteries that were replaced under warranty free of charge by Apple for premature failure.

I've noticed that one of my 4 MagSafe chargers is not charging correctly any more even though it can power the computer just fine. It took me a while to figure out that was the case as I kept incorrectly concluding that the problem was in the battery. There have been reported problems with the chargers failing in this way.

I think that because a modern laptop can now have intelligence in the charger, the battery itself, and the power management functions of the laptop, we are seeing problems that are hard to debug.

I have also gone through 2 batteries in just over 2 years. The first was fully recharged quite a bit seeing as I was always working remotely. The second battery went through much fewer charge cycles since I was working from home and I was making attempts at improving the life of the second.

Each of the batteries I purchased died out at about the same time. Unless I got two bad ones, it seems to me that mac batteries weren't of the best quality during the time of my purchases.

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