Battery use... which is it?

I took my MBP into the Apple store last night to check it out before buying it from a friend. The guy at the genius bar tells me to not leave the computer plugged in all the time because it doesn't allow the battery to keep the cells fresh. He says to drain it to 5% and then charge to 100% instead of leaving it plugged in. I tell him that sometimes I use my computer all day and that I'm worried about having to charge it over and over and he says that the battery has 1000 cycles and should last 5 years.

I called Apple support today for an issue and asked the guy about it because I noticed today that the battery was draining super fast and he tells me that he tells customers the opposite. He says that unless it absolutely has to be portable, he recommends to always leave it plugged in.

So which is it?

Well this is what Apple's says about it regardless of who you talk to at the Apple stores: Apple - Batteries - Notebooks

Unless you bought your laptop as a desktop replacement then you will have to unplug it and use the portability eventually. I have a 5+ old Mac laptop that still has the original battery and I never kept it plugged the whole time. What you do want to avoid is to completely drain the battery more than once a month (a calibration). Just recharge it whenever you get a chance but I always charge it to full once I plug it in. The benefit of Lithium batteries is that you can charge them whenever you want and not have the memory problems that other batteries had.

The people I've read with the most battery problems seems to be the ones that keep it plugged in. The stories usually go the same. They have something like 40 battery cycles with a 2 or more year old battery but the battery no longer holds a charge. I rarely read about someone who has high battery cycles and a sudden dead battery. Usually with high battery cycles the battery eventually holds less than the maximum amount when it was new but it doesn't do the sudden death can't hold a charge anymore problem.

Of course there are always exceptions but that's what I have noticed when I read about battery complaints. Although you should use your laptop the way you want/need to because what's the point of having these machines when they don't work the way we want them too?

Thanks for the response. I have another question.

With my MBP plugged in, is it normal for it to stick to 98% instead of 100%? I haven't seen it hit 100% yet. Also, the first day I didn't have it plugged in and it seemed to drain the battery super quick. What's a good test I can do to see if my battery holds a charge the way it's supposed to?

I don't know if it's normal for the new MBPs but my MBP which is the previous generation always charges to 100%. It does seem to take longer to charge the last percentage though.

If your battery is draining quickly make sure that you don't have unnecessary things on like the keyboard lights, Bluetooth, wireless airport card, etc if you are not using them. The battery hours Apple advertise definitely are not with everything on. When I first got my MBP the battery life was also not close what was advertised because everything was on by default.

I don't know about a good test to see if your battery holds a charge but if you fully drain it and then fully recharge it just use it unplugged and see how many hours you are getting. Usually a bad battery will die suddenly after a few minutes of usage even though you just fully charged it. If it's just draining quickly from usage then it just means that your MBP is using too much power but you should still get several hours on a fully charged battery on the new MBPs. A battery that can't hold a charge will die suddenly as I have described.

HonestIllusion said:

With my MBP plugged in, is it normal for it to stick to 98% instead of 100%? I haven't seen it hit 100% yet. Also, the first day I didn't have it plugged in and it seemed to drain the battery super quick. What's a good test I can do to see if my battery holds a charge the way it's supposed to?

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When the battery charge is above a certain level (I'm not exactly sure, but it might be 95%), the computer will not charge it at all. If you unplug it, then use the battery for a bit and plugged it in again, it should charge back up to 100%.

I'll unplug it and then wait a while and plug it back in to see if it hits 100%. I'll also try seeing how long it will last with simple usage like iTunes and web browsing. I do have bluetooth turned on for my magic mouse, but I don't necessarily need to use it. I'm mostly worried about class because I'll take it to school on Wednesdays to take lecture notes and I want to make sure it doesn't die on me.

Wait.. I installed Coconut battery as requested by a friend. When I check it, it says the battery has a capacity of 98%. It also says that the original capacity was 6900 mAh and that the current is 6794. Is this meaningful?

I don't know if Coconut battery is that accurate about its stats. The reason I say that is that I've read about some people doing a battery calibration and their battery health and capacity increased. You can also use the build in battery stats from Apple by going to the Apple icon in the menu and then click on About this Mac and go to more info where you will find the battery power section.

Anyway if it's accurate then it means you lost some of your maximum battery capacity meaning your battery only holds 98% of what it used to.

Although if you constantly monitor your battery usage you will become one of those paranoids battery MBP users. These are people who are afraid to use their MBP in any way different than what they think works best for their battery. If you want to box yourself into that limited kind of usage then that is a choice you have to make. I personally would prefer to use my MBP in a way that works for me regardless of how good or bad it is for the battery. The batteries aren't exactly cheap but they are replaceable.

Yeah I would rather enjoy the computer, I don't see myself being that type of person. All I really care about is that it lasts me during my 3 hour class.

HonestIllusion said:

All I really care about is that it lasts me during my 3 hour class.

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Only way you will know for sure is to time yourself with an actual watch until the battery is fully drained from full. It's good to do this just so you have a reference point for what is normal with your computer. Dimming the display also helps to save battery life.

The maximum hours I've got with my MBP was around 6 hours with Bluetooth and wireless off and the screen to about half brightness. The only thing I had plugged in was a USB mouse so I would have had a little more battery life without it plugged in.

HonestIllusion said:

Wait.. I installed Coconut battery as requested by a friend. When I check it, it says the battery has a capacity of 98%. It also says that the original capacity was 6900 mAh and that the current is 6794. Is this meaningful?

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My Girlfriend just bought me a new 13" MBP and it shows that my battery has a capacity of 98% should I go and exchange it for a new one as I have only had it for 2 days now???

HonestIllusion said:

With my MBP plugged in, is it normal for it to stick to 98% instead of 100%? I haven't seen it hit 100% yet.

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Try another outlet to charge your MBP.
I have the same problem here in Qatar with some of my outlets. The outlets in my office charge my MBP battery to 98% with a green light. In my bedroom for some reason the outlet charges it to 100%. Go figure.

FYI... My MBP is 3 years old with the original battery.