Truth about Battery Charging

[Scottyent]

Hey all, I was wondering what kind of knowledge you guys have about the LI-ION batteries in this badboy. I see a lot of conflicting things online, and from what I gather...you shouldn't be charging overnight, and you shouldn't frequently do full cycle discharge. So, what is the best practice? Charging semi frequently and shutting it off at night? I dislike this because I use the phone as an alarm, and don't want to wake up with the battery starting at 90 for the day.

Also, if you're not supposed to charge overnight (which i've done with many other phones and they were fine), then if I do get the media dock...it would charge overnight every night as my alarm clock.... isn't that bad for the battery? I'm just concerned about ruining my battery, what have you guys heard, and what effects have you seen?

 

[sooper_droid12]

Lithium ion batteries should never be allowed to discharge or reach a low level of charge and then fully charged (i.e. full cycle charges). A friend of mine has his mind set on the fact that you need to fully discharge a battery and charge it to full to maintain its longevity. The opposite though is true: 1) Each battery has a finite number of charge/discharge cycles so no matter what, every battery will eventually decline and die (i.e. these batteries do not have memory); 2) Several partial discharges with frequent recharges are favorable over one deep one; 3) Since our batteries are being measured by a gauge, 1 full discharge in 30 will keep the battery's circuitry calibrated with the gauge.

These are just some tips. Again, no battery is going to last forever and typical life for Li-ion batteries are 2-3 years. And don't bother getting a spare battery, unless you're one of those users who just blasts through batteries.

 

[rickshadey]

Nice to know about the battery life. I'll keep that in mind. But this thing charges quick and you didn't address the charging over night. I also use my phone for an alarm and usually plug that hing in on my night stand. Can you "over charge" them by leaving them in overnight?

 

[chefboyardee]

This is very interesting information, sooper. Can you go into a little more detail? Specifically, regarding *not* fully discharging.

I've anecdotally seen this help my phone. Days 1-5 or so, the battery life was horrible, and it wasn't just because it was a new toy and I was using it heavily - I still use it just as heavily, with more apps installed (so probably more going on in the background), but after 3 or 4 full discharges I'm finding my battery lasts much, much longer than it initially did (we're talking twice as long easily).

I'm not refuting your point, as I know nothing about battery types short of what I've read on this forum. But I am curious if I'm just seeing a placebo effect as I've gotten used to the phone, or if there's some logic that actually allowed my battery to last longer, but *isn't* tied to a full discharge.

If you have any very easy to read tutorials on L-ION batteries and how they work I would be very interested to read it. But the ones that get real heavy into the physics of it make my eyes water. So it would have to be written in more plain english for me to understand

Either way, thanks for the reply, very good food for thought.

 

[KBlack]

I had the same concerns a few days ago and my research lead me to this:

Charging lithium-ion batteries

Check this guy's credentials at the end of the article. I would tend to trust him, and I double-checked the info somewhat successfully on other sites. The Droid uses a Li-ion POLYMER battery as opposed to straight Li-ion, but he specifically states that

[FONT=Verdana, Arial, Helvetica, sans-serif]The charge process of a lithium-ion-polymer is similar to lithium-ion. These batteries use a gelled electrolyte to improve conductivity. In most cases, lithium-ion and lithium-ion-polymer share the same charger. [/FONT]

Also note that Motorola's Droid user manual (page 42) states that their batteries have safeguards which prevents the batteries from suffering overcharge damage, so I wouldn't be worried about letting the droid on the multimedia dock all night long to use as an alarm clock, which is what I'm gonna do when I get this phone.

Also, Hi, I'm new.

 

[chefboyardee]

Welcome and thanks for a very helpful first post!

So if I'm reading that right, it was kind of a placebo effect - the full discharge cycle didn't help the battery life, but *may* have helped the sensor, so while on day 1 and day 10, I was seeing different values on the phone (say, 30% vs 70% at end of day), in reality the battery life on both days was the same, but I was seeing a different reading in the OS?

Does that make sense to someone who knows what they're talking about?

 

[KBlack]

Glad I could help. Since it's the phone that decides when it switches off to prevent overdraining (is that even a word?) the battery, the sensor conditioning theory makes sense, but I can't confirm anything.

I should add that I currently own a Motorola KRZR K1, which uses a Li-ion battery, and even if I leave it plugged in all night long, the charging indicator light stops after roughly 2 hours and I don't feel like my battery is hot in the morning. If that's worth anything, it means that Moto's charge sensors are quite reliable, because I've had the phone for two years and the battery's drop in capacity is barely noticeable.

 

[Redflea]

Either here or on HoFo, someone posted some Nasa research on Li-ion batteries that looked reliable....

Here's the post:

In general, it's not a good practice to let the battery be drained completely during each use cycle; Li-ion batteries do not like to be kept discharged and warm/hot at the same time at all, and they don't like being kept fully charged for long, especially at elevated temperatures (which is any temperature over ambient)--that's why they are shipped typically at a 40-50% SOC. However, you may do a full discharge/recharge cycle from time to time, maybe every one or two weeks, to recalibrate the battery status gauge.

In general, Li-ion batteries last longest during partial (swing) charge/discharge cycling around the 50% state-of-charge point (SOC), plus/minus 20-30 % SOC. NASA (and other) tests performed to qualify Li-ion batteries for satellite applications showed that using such swing cycling around the 50% SOC point can increase the battery life 5-10 times.

 

[craighwk]

And that's that.

 

[KBlack]

Who can argue with NASA?

/topic

 

[geeek204]

Lithium ion batteries should never be allowed to discharge or reach a low level of charge and then fully charged (i.e. full cycle charges). A friend of mine has his mind set on the fact that you need to fully discharge a battery and charge it to full to maintain its longevity. The opposite though is true: 1) Each battery has a finite number of charge/discharge cycles so no matter what, every battery will eventually decline and die (i.e. these batteries do not have memory); 2) Several partial discharges with frequent recharges are favorable over one deep one; 3) Since our batteries are being measured by a gauge, 1 full discharge in 30 will keep the battery's circuitry calibrated with the gauge.

These are just some tips. Again, no battery is going to last forever and typical life for Li-ion batteries are 2-3 years. And don't bother getting a spare battery, unless you're one of those users who just blasts through batteries.

Agreed, I always have people telling me to discharge fully, don't overcharge, etc... and I always have to go on with this story.

The batteries that benefit from this type of charging and discharging are NiCd and NiMH cells; which were once very popular until lithium-ion technology came along. Lithium-ion does not have this "memory" effect and does not benefit from fully discharging, conversely, it looses capacity in these discharges.

Lithium-ion (or lithium-ion polymer) degrades based on the amount of "charging cycles" that it undergoes; each full charge (0->100%) counts as one full cycle. So, as sooper said partial discharges are more favorable over full discharges as they only count as a fraction of a full charge cycle.

As for the charging overnight, modern charges, phones, and batteries all include circuitry to prevent the battery from being overcharged. You should be fine leaving it plugged in overnight.

 

[will_m68]

I have a dock at work and at home, so my phone is in the charger most of the time. I'm taking it as this is a bad thing?

 

[craighwk]

I have a dock at work and at home, so my phone is in the charger most of the time. I'm taking it as this is a bad thing?

Nope, not at all.

 

[admorris]

Nope, not at all.

Based on what I have read on here and other sites, I would take your phone off the charger at work a couple days a week and let it get down to 50% or so and then recharge. Maybe once a month or so do a full cycle charge to "condition" the internal gauge.

 

[budwizer]

I had the same concerns a few days ago and my research lead me to this:

Charging lithium-ion batteries

Check this guy's credentials at the end of the article. I would tend to trust him, and I double-checked the info somewhat successfully on other sites.

You beat me to posting this. I would also add the following link as well:

How to prolong lithium-based batteries

 

[chefboyardee]

Based on what I have read on here and other sites, I would take your phone off the charger at work a couple days a week and let it get down to 50% or so and then recharge. Maybe once a month or so do a full cycle charge to "condition" the internal gauge.

oh good, i was just about to post this but saw your post on preview:

Nope, not at all.

Thanks everyone for the great info in this thread. Learned more here about the battery in this beast than anywhere else.

I thought I had everything understood until I saw the quote above.

and they don't like being kept fully charged for long

In general, Li-ion batteries last longest during partial (swing) charge/discharge cycling around the 50% state-of-charge point (SOC), plus/minus 20-30 % SOC. NASA (and other) tests performed to qualify Li-ion batteries for satellite applications showed that using such swing cycling around the 50% SOC point can increase the battery life 5-10 times.

Doesn't the above say that we should try to charge it at around 50% discharge, not keep it at 100% all the time?

but now it seems like it should be partially discharged sometimes. which makes sense.

so again, thank you everyone for a lot of very good info (and backed by research!)

 

[TonyG]

No, it just means that if you had a choice and could live with only a half of your battery capacity, the battery charged to 50% SOC would last longer than one always fully charged... We're trying to ensure the most capacity with a decent cycle life under average use conditions--and keep the battery safe... NASA is just trying to get the longest cycle life at a cost of low usable capacity, because it's very, very expensive to change batteries in space!

 

[admorris]

And we know how efficient NASA is with money

 

[sooper_droid12]

The main culprit in a near full discharge and subsequent recharge is the strain that it puts on the battery. Remember that "recharging" a battery is a chemical process that also generates heat. These "full" recharges, no matter how slow the rate, will always result in some heat production. Heat is a detriment to battery life. When it all comes down to it, what kind of cycles you use, 40%, 50%, whatever... mitigating the generation of heat will ultimately help retain battery performance over time.

 

[TonyG]

Well, it's only partially like that... While it is true that high temperatures will always shorten battery life due to an increased rate of all side reactions between the electrolyte and electorde materials, a slow charge will NOT heat the battery much at all, since any excess heat will easily dissipate. What affects the battery life most during full charges and discharges is the mechanical stress that slowly grinds the electrode material particles into a finer and finer powder, thus causing the particles to lose electrical connections, develop microcracks etc etc. This happens because the volume of the electrode materials changes by 7-11% or even more during each lithiation and delithiation (charge/discharge) reaction. It's a wonder that Li-ion batteries work as well as they do--because in principle they shouldn't!

 

[Scottyent]

I'm glad that this thread became so useful! And now I don't have to worry about the multimedia dock

 

[mike84]

I am pretty confident that the phone stops charging when the battery is full (even when plugged in) the charge light goes off when the phone is charged. I am glad to read about the full cycle/full discharge as i was under the impression that that was better as well. Very happy i stumbled upon this thread. Thanks guys!!

 

[Scottyent]

More food for thought, and by that I mean more questions about batteries. Hopefully more people can give us some answers and continue to help us all out!

What about charging the phone via a cigarette USB adapter? I was told by a Verizon rep (a very rude one) that I should not charge the phone through a car charger for more than 15 minutes at a time. This didn't make much sense to me because I figured it just charged it slower. Any truth behind that advice?

Does using the phone while it's charging hurt the battery? Either while charging in the wall or charging in the car, I feel like I've read and heard on and off that if you use it while you're charging it, it will shorten the life of the battery. Lets get to the bottom of that!

Thanks everyone for your extremely helpful posts!

 

[eezjb]

This thread should b sticky

 

[az_r2d1]

Gusy what are we talking about here. These Phones sell like hot cakes and the batteries will probably be very cheap after a while to replace. It's a replaceable battery after all. Modern chargers do not overcharge. The phone isn't even hot when you leave it charging overnight
For the people who don't have a charger everywhere, buy a CHEAP (monoprice) micro usb cable and hook it to your usb port on your computer at work. This way it will charge when at work as well and keep it full.
Stop worrying about nothing.