How Lithium-ion batteries work

mlass

Member
Silver
Jun 19, 2007
678
0
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#1
To help educate people on Lithium-ion Batteries

http://electronics.howstuffworks.com/lithium-ion-battery.htm

Some of the info...

Lithium ion chemistry prefers partial discharge to deep discharge, so it's best to avoid taking the battery all the way down to zero. Since lithium-ion chemistry does not have a "memory", you do not harm the battery pack with a partial discharge. If the voltage of a lithium-ion cell drops below a certain level, it's ruined.

They are extremely sensitive to high temperatures. Heat causes lithium-ion battery packs to degrade much faster than they normally would.

...these batteries have the ability to burst into flames occasionally. It's not very common -- just two or three battery packs per million have a problem -- but when it happens, it's extreme.

If the battery gets hot enough to ignite the electrolyte, you are going to get a fire.
 

Megalobyte

New Member
Jul 31, 2008
14
0
1
#2
To help educate people on Lithium-ion Batteries

http://electronics.howstuffworks.com/lithium-ion-battery.htm

Some of the info...

Lithium ion chemistry prefers partial discharge to deep discharge, so it's best to avoid taking the battery all the way down to zero. Since lithium-ion chemistry does not have a "memory", you do not harm the battery pack with a partial discharge. If the voltage of a lithium-ion cell drops below a certain level, it's ruined.

They are extremely sensitive to high temperatures. Heat causes lithium-ion battery packs to degrade much faster than they normally would.

...these batteries have the ability to burst into flames occasionally. It's not very common -- just two or three battery packs per million have a problem -- but when it happens, it's extreme.

If the battery gets hot enough to ignite the electrolyte, you are going to get a fire.
Good info, this seems to be consistant with the info on the Battery University website, the one thing they mention, that I'd add to the above, is that while you should try to avoid (when possible) letting the battery run all the way down, 1) Little chance of the battery actually getting ruined if it does happen occasionally since the iPhone shuts down before the battery's voltage gets critically low, and 2) For so called smart batteries, like the iPhone's, which have a power meter/gauge, you do need to periodically, maybe once a month or so, do a full charge, then let the battery run down to where the phone shuts down, then give it another full 4 hour+ charge, this calibrates the power meter and doing it once every 30 cycles doesn't apparently do any serious damage to the battery.

But, the one thing I keep reading is that people who intentionally let the battery run down all the way most of the time aren't doing their battery any favors. Once in a while is fine, just not all the time, best to keep it charged when possible than to do a full discharge/charge each time.

I sure do wish the 3G had a user replacable battery, that would alleviate much of the anxiety we all seem to have about this.
 

psylichon

Genius
Moderator
Oct 31, 2007
16,591
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40
Philly
#3
Great thread and first reply. There is a lot of misinformation out there, but everything stated so far seems 100% spot on for the iPhone.

Everyone should link here when any questions regarding proper battery care come up.
 

Megalobyte

New Member
Jul 31, 2008
14
0
1
#4
Great thread and first reply. There is a lot of misinformation out there, but everything stated so far seems 100% spot on for the iPhone.

Everyone should link here when any questions regarding proper battery care come up.
Thanks!

While we're discussing battery care, and by extension, giving yourself more battery life, here is my experience so far.

I was having the same issue many are, not enough battery power to last a full day.

First, I think part of it, at least for me, but I'd bet others too, was that since the 3G iPhone is so new to me, and is such a cool gadget, I can't help but tinker around with it for fun, you know, see what it can do, and how well it does it, so, I think that for the first week or so, I was probably playing around with it a little more than normal, doing speed tests, trying new Apps, just messing around with a new toy. So, I'd guess that once the novelty wears off, and I start using it like I was using my gen 1, I'll have better battery life, but, whether that's true or not, here is what I think I'm seeing also.

I think that the biggest drain on my battery was using 3g for calls. I have found that if I try to use Edge for my calls, especially longer calls, I can keep 3G on all other times, use it for a fair amount of web browsing, and still get pretty good battery life.

I was originally thinking I should leave 3G off unless and until I wanted to surf, then when done, disable it again, but, what I'm finding is, I can leave 3G on all the time, except if I know I'm going to be spending significant time on the phone, at which point I'll use Edge, which works just fine for phone use, and save the 3G for web browsing, and doing it this way has given me much better battery life, where before I was getting close to 20% by the day's end, I now have 50%-70% at the end of a day, assuming I started the day with a full charge.

I would think the reason for this is, 3G does use a lot more power than Edge, it's not as noticeable when you're using 3G for the net because most people don't surf the net on an iPhone for 10-20 minutes to an hour at a time, but lots of us do talk on the phone for this long, if you're talking on the phone on 3G for a while, that's a lot of extra power you're using, where internet use is usually for shorter periods of time than phone use, at least for me.

So, all I do now is leave it on 3G, if I know I'll be using the phone for a bit, I'll use Edge for that, then get back on 3G to have it ready for me if I want to do some internet, and I seem to be doubling my battery life lately, of course this really only holds true if you do speak on the phone for more than just a minute or 2.

In a nutshell, I can use 3G for a good amount of net browsing throughout the day, and have plenty of battery power left by day's end, if, I try to use Edge for phone calls as much as possible. This works for me, it may, or may not for you. :)