What I've learned about Nook batteries

[2010bc]

I've been having battery troubles as some of you know. Thanks again to those of you who have tried to help me. Here are some things I have found out. The Nook has a Lithium-polymer (LiPo) battery, not Lithium-ion. It says so on the battery. It is possible to damage Lithium batteries by over-charging them. Barnes and Noble customer service told me overnight is too long. Unplug your nook as soon as it is fully charged. (You'd think they would mention this in the users' manual.) The guy at Batteries Plus, a store that sells batteries only, said Lithium batteries don't need to be deep cycled. Some of the other battery types, like NiCads can "form a memory," so discharging them completely from time to time may extend their life. Lithium-polymer batteries can be damaged by discharging them too deeply. It may not be such a good idea to deep cycle them. (I read this in "Fly RC magazine, issues 78 and 79.) I don't know if the Nook has some sort of cutoff built in, It may. Or not. I could be wrong. I'm just sayin'. Please don't take this as the gospel truth. I'm just passing along some things I have read and have been told. Please don't sue me.

[iharley]

Thanks for sharing. I noticed today, for the first time (so it might be related to 1.3) that my nook, while charging all night, actually went down. I woke up and saw it at 99%. Figuring it would hit 100% soon I just let it keep going. 10 minutes later it was 95%. I guess I won't be treating it like my cell phone (charging when not using) and just let it get down to 20% or so then charge back up.

[GeoffreyF]

Much of what you are saying is incomplete or incorrect.

1) Lithium Polymer is a kind of Lithium Ion battery.  Generally Lithium Polymer is an improved Lithium Ion design that is lighter weight and lasts longer.   It works the same ways as other Lithium Ion batteries.   All batteries use Ions by the way.  Ions are simply atoms which have an electronic imbalance and that is how batteries work.  

2) Individual Lithium Ion and Lithium Polymer battery cells can be over charged.  At the level of hobbyists who build their own chargers or build chargers designed for rapid charging this is an issue.  HOWEVER, modern consumer devices such as the nook have electronic circuits in the battery pack itself and in the device that ABSOLUTELY PREVENT OVERCHARGING.  Therefore, this is not an issue in the nook.

3) You are correct, no lithium battery of any description needs to be deep cycled or even cycled.  In fact, it just wears them out.  Also Lithium batteries do not get a "Memory" as NiMh and NiCad batteries do (these tended to be what was included in older equipment).

4) Deep discharging of any Lithium battery is bad and can ruin them.   The Nook and other modern consumer devices will prevent this.   However, if you store the battery for many months, it's a good idea to put a full charge on it and then check it periodically.  It can become deeply discharged from just sitting there over a VERY long period of time.

5) Customer service was wrong in telling you not to charge overnight.  They are mistaken.  In fact, the nook stops charging automatically when the battery reaches a fully charged state. This is what the yellow light means ... when it is on, the nook is charging and when it is off, the nook is fully charged and not charging.

6) If the nook fails to charge or discharges with the included charger and cord then the charger or the nook is defective.  To figure out which is the problem, try using the USB charger provided for an iPod.  If this works, you have a bad charger.   Charging from a laptop or computer may not always work.  this is an issue with the charging computer, not the nook.

In general, the nook circuits protect from mistakes.

There is only one thing that a consumer can stumble into with a nook.   That is failure to charge the nook fully before discharging when you first get the nook (or a new battery).  It is safest to do this with the Nook charger and charge cord.  Charging it with a computer the first time may not work properly.   The warnings on the box are pretty explicit about this.   If you do not do this then the nook battery will be forever under-performing.   It's OK to use the nook while it is charging ... just don't disconnect it and discharge it until it is fully charged the first time (yellow light).

Once this first time process is followed, it is just fine to charge the nook for a bit and then disconnect it and use it as it's convenient.   It does not harm the nook battery in the least bit.

If anything that I've said here doesn't seem true for your nook AND you have tried it with the nook charger and cord, there is something wrong with the nook or its battery.

[Scooter742]

GeoffreyF is absolutely correct.  Assuming your Nook hardware isn't defective, there is no way to accidentally "overcharge" your battery by leaving it charging overnight.

[2010bc]

Scooter and Geoffrey--  

Thank you, thank you, thank you.  I only started all this because the supervisor (Danny, I think) at BN customer service was so adamant about the "fact" that I would ruin the battery if I charged my Nook overnight.  I really appreciate your help with this.

[icebike]

iharley wrote:

Thanks for sharing. I noticed today, for the first time (so it might be related to 1.3) that my nook, while charging all night, actually went down. I woke up and saw it at 99%. Figuring it would hit 100% soon I just let it keep going. 10 minutes later it was 95%. I guess I won't be treating it like my cell phone (charging when not using) and just let it get down to 20% or so then charge back up.

Ah, well then you have just proven that the info given to 2010BC was wrong.

The nook stopped charging as soon as it got to 100% (just like you would expect) and started using its battery.

You can't overcharge the nook.  It will cut off when its full. 

What Geoffery said is spot on.  

Especially the bit about a FULL charge when you first get your nook.

[read2010]

I bought the Nook one week ago.  I fully charged it before using it the first time.  So far, the battery goes down from 100% to 20% after only 5 hours reading.  I keep airplane mode on when I am not using the Nook.  I am disappointed in the battery life. 

[icebike]

read2010 wrote:

I bought the Nook one week ago.  I fully charged it before using it the first time.  So far, the battery goes down from 100% to 20% after only 5 hours reading.  I keep airplane mode on when I am not using the Nook.  I am disappointed in the battery life. 

How many times did you let the battery run down to zero, (automatic shutdown)?

Do it.

Then charge it fullly.

[2010bc]

I e-mailed customer service with these questions.  Here is the answer I got from Barnes and Noble Customer Service:

Dear Customer,


Thank you for your inquiry regarding battery care.

Answers;

Question (1) can you overcharge the Nook battery and will charging the 
battery too long (overnight) damage it? 
Answer: Yes

Question (2) can you discharge the Nook battery too deeply and will deep
cycling damage it
Answer: No

Question (3) is it necessary or not advisable to cycle the batteries 
every 30 charges or so?
Answer: No


Visit www.bn.com and click on the options that appear in the upper 
right-hand corner to view information about your order.

We look forward to your next visit.


Sincerely,

Ray
Customer Service Representative
Barnes and Noble

[icebike]

Wow.   Just WOW!  Unbelievable.

In this day and age to put out a product that you have to babysit the charging!  Unheard of.

An then to not mention it anywhere in the manual!!!  What will Kindle make of this when they see it.

But the big question is HOW did they manage to develop such a battery system that is at risk of overcharging a Lithium Ion battery.  The industry goes to great lengths to prevent this due to the risk of fire and explosion from uncontrolled charging.

Even the Battery University states it virtually impossible to overcharge a LiOn battery because everybody builds charge controllers into their device.  

[AlanNJ Inspired Bibliophile]

I would think you CAN overcharge it (if the Nook's charge monitoring system fails).  Otherwise not.

Anything is possible.

[2010bc]

O.K.  Here is what I learned by talking to Barnes and Noble Customer Service today, 4/29/10.  

The Nook has a Lithium-polymer battery (LiPo).

1.  If you continue to charge your Nook after it is fully charged, it will begin to discharge.  Discharging may continue until the battery gets so low the Nook will freeze.  If this happens, take the battery out, plug the Nook in to a wall outlet, then replace the battery and charge it back up.  B&N recommends you unplug your Nook as soon as it it fully charged--about 4 hrs. if the battery is very low.

2.  You do not need to cycle the battery.  There is no clock, switch, memory, etc, that determines the high and low points on your Nook battery. Neither the battery nor the Nook will develop a "memory."   B&N recommends that you charge your nook before it gets below 20%.  If the battery gets too low, your Nook may not have enough power to operate the e-ink screen and may freeze.  If this happens, take out the battery, plug the Nook into a wall outlet, then replace the battery and charge it back up.

So that's it.  I now know more about batteries than I ever wanted to, (or maybe I don't know anything).  Now that I'm pretty sure I'm not going to blow up my Nook, I think I'm done with this topic.  If you don't agree with this information, it"s YOUR turn to call CS. 

[Jason_Corner]

I think this information has to be flat out wrong, or such a terrible oversight on B&N's part that it would invite litigation.  The Nook batteries would be unique in consumer electronics in such a carelessly crafted battery design.  However, I believe it to be wrong because (if I recall correctly) overcharging the battery would result in the battery expanding causing explosion or at the very least cracking the battery and it leaking its innards.  Since no one has noticed any change in the battery's appearance, any overheating from the battery, any explosions, or any other problems aside from the battery ceasing to hold a charge, this seems unlikely. Besides, both the Nook manual and the device itself seem to indicate that it stops charging when the battery is full. 

More likely is one of two issues....

1) Their are defective batteries that have been shipped. 

2) The battery contact issue where the battery is not making proper contact with the leads in the Nook.  I've talked to people who have had this issue, and putting a small piece of paper in the top right of the battery compartment has fixed their battery issues.  

Plus, I've left my Nook on the charger for days sometimes, and I have no issues with Battery life..  Although since 1.3 I've noticed I've had to charge mine more often as a result of some heated Sudoku games.

[icebike]

I still disbelieve these people.

There is a battery controller, you can see it on the motherboard.  These all function the same way.  Having left my nook plugged in for days I can assure you it does not discharge after it is fully charged.

I'm sure you reported exactly what they said.  But I'm betting you talked to someone with no technical knowledge, who couldn't read a circuit diagram if his life depended on it, and was saying what ever is necessary to get  you off the phone.

[Jason_Corner]

icebike wrote:

I still disbelieve these people.

There is a battery controller, you can see it on the motherboard.  These all function the same way.  Having left my nook plugged in for days I can assure you it does not discharge after it is fully charged.

I'm sure you reported exactly what they said.  But I'm betting you talked to someone with no technical knowledge, who couldn't read a circuit diagram if his life depended on it, and was saying what ever is necessary to get  you off the phone.

I agree with Icebike 100%; talking with my coworker, who was an electrician in the Navy, he told me that you could overcharge the battery in one of two ways.  You could fry the controller circuit that regulates the charge - all battery chargers have one, otherwise all the nooks would be overcharging the second the battery was fully charged.  The other way was to increase the amps, such as by cutting an electrical cord and hooking the two wires directly up to the contacts on the battery.

Either way, an overcharged battery starts to heat up, which causes the battery acid to turn into a gas... gasses expand, so it either ruptures the battery case leaking acid or explodes.  No Nook has done that yet, so its a pretty safe assumption that this isn't the problem. 

That being said, the Nook discharging once it is fully charged seems like it could be an actual issue, but it seems to me that this is something that could have been fixed with a patch unless it was hardwired into the circuit board.  Even if this is the case, the battery shouldn't have such a drastic down turn in life if you have left it to charge...The Nook isn't doing anything, so the battery should hold a pretty good charge.

[Elfsshadow]

I have to wonder if it is actully discharging.  Seems more likely the battery is still charging and the nook is updating its battery estimate. 

[eDigest]

One additional point:

Question (3) is it necessary or not advisable to cycle the batteries every 30 charges or so?
Answer: No

The question requests an either-or response, not yes or no.

Either way, "No" is misleading.  It may not be "necessary" but is is advisable according to "official" responses to v1.3 battery life issues posted in these forums.  It is also advisable according to a previously posted link about lithium batteries.

[flyingtoastr Scribe]

icebike wrote:

Wow.   Just WOW!  Unbelievable.

In this day and age to put out a product that you have to babysit the charging!  Unheard of.

An then to not mention it anywhere in the manual!!!  What will Kindle make of this when they see it.

But the big question is HOW did they manage to develop such a battery system that is at risk of overcharging a Lithium Ion battery.  The industry goes to great lengths to prevent this due to the risk of fire and explosion from uncontrolled charging.

Even the Battery University states it virtually impossible to overcharge a LiOn battery because everybody builds charge controllers into their device.  

OR they're just covering their asses on the off-chance that you have a defective unit. There probably is a charge controller in the battery unit, but why leave it plugged in anyway?

[AlanNJ Inspired Bibliophile]

I keep mine plugged in because, like my iPhone, I charge it overnight most of the time.

[very-simple]

Me too.  I actually keep a charger in the outlet near my nightstand, and I just plug the nook in there when I go to sleep at night so that it's fully charged in the morning.  I bought a second charger for just this purpose because it was too much hassle to unplug and replug from the outlet, since I have to move a fairly heavy piece of furniture every time I want to access the outlet, and I didn't want to have to get out of bed to go plug the thing back into my computer as I was falling asleep.