Prolonging battery life

[viewfly]

Hi everyone,

I think something like was probably posted before, but a refresher on it came up in the 6131 Thread on WA.

I was doing a little research on charging li-ion batteries, the kind in our phone.

It supports that charging frequently, without going to a dead battery, is the best way to preserve your battery. Going to full discharge, although somewhat protected by the phone electronics, is not what Li-ion batteries like.

Some of us have gotten into the habit of charging our phones in the morning, each day, during breakfast or whatever, so we have a full charge during the day. It takes only 2 hours max on the 6131, and most times it is only 1/2-1 hour to top it off. Most people charge at night, or worse, charge it the whole night, which is not a good idea: overcharging will kill a battery.

"A lithium-ion battery provides 300-500 (full) discharge/charge cycles. The battery prefers a partial rather than a full discharge. Frequent full discharges should be avoided when possible. Instead, charge the battery more often or use a larger battery. There is no concern of memory when applying unscheduled charges."

Also, the battery's lifetime decay starts the day of manufacture, so buying a 'fresh' battery, but an old one (or keeping it around as a unused spare) is not a great idea. So maybe those cheap OEM-like batteries I sometimes see, are outdated or old. Buyer beware!

But one thing I didn't know, regards the battery's charge Icon on the phone. I don't know if it is true for Nokia's but apparently it gets recalibrated only with a full discharge. So the recommendation is to full discharge every 30 cycles (in our case once a month).

"Although lithium-ion is memory-free in terms of performance deterioration, batteries with fuel gauges exhibit what engineers refer to as "digital memory". Here is the reason: Short discharges with subsequent recharges do not provide the periodic calibration needed to synchronize the fuel gauge with the battery's state-of-charge. A deliberate full discharge and recharge every 30 charges corrects this problem. Letting the battery run down to the cut-off point in the equipment will do this. If ignored, the fuel gauge will become increasingly less accurate. "

It doesn't mean that the battery has less charge, only that the phone's battery meter thinks so...and this may turn the phone off early. I don't know for certain.

So the practice we have is a good one, but every month , let it go down to shut off. Whatever works, or at least beware this may be going on.

Reference: http://www.batteryuniversity.com/parttwo-34.htm

Wikipedia has also some info and it agrees with what my professional battery co-workers have told me : http://en.wikipedia.org/wiki/Li-ion_...n_battery_life

"A unique drawback of the Li-ion battery is that its life span is dependent upon aging from time of manufacturing (shelf life) regardless of whether it was charged, and not just on the number of charge/discharge cycles. This drawback is not widely publicized"

and

" Unlike NiCad batteries, lithium-ion batteries should be charged early and often. However, if they are not used for a longer time, they should be brought to a charge level of around 40%. Lithium-ion batteries should never be "deep-cycled" like NiCd batteries"

The exception being, the first time you get the Li-ion battery: do 3 full charge/discharges first, to maximize battery life for future partial charges.

The daily morning charge is working out well for all of us. I like having a full battery during at start of the day, esp after 9/11...never know when you wish the battery was not half empty. But be careful not to overcharge, unless you know for certain that the charger has turn off protection. The Nokia 6131 manual specifically states not to leave the charger on longer than necessary.

vf

[Charlyee]

viewfly, thanks for the great information. How about asking one of the moderators to make this into a "sticky" so this one does not get buried like the one posted by Tony E did.

[Jay2TheRescue]

Originally Posted by Charlyee

viewfly, thanks for the great information. How about asking one of the moderators to make this into a "sticky" so this one does not get buried like the one posted by Tony E did.

I vote for sticky status too. I've noticed that the past few years the phones I've gotten since my v60 have been much better than my V60 and StarTac were. My StarTac had to have its battery replaced at 18 months, and my V60's battery was limping on its last legs when I bought my V551. My V551 is about 3 years old now and I still have no problems with it after charging nightly.

-Jay

[Tony E!]

Originally Posted by Charlyee

viewfly, thanks for the great information. How about asking one of the moderators to make this into a "sticky" so this one does not get buried like the one posted by Tony E did.

Good memory Charlyee....

I'll just make this one a sticky since it has the same info and link as the one i posted.

[viewfly]

Originally Posted by Tony E

[/b]

Good memory Charlyee....

I'll just make this one a sticky since it has the same info and link as the one i posted.

Thanks Tony. Making this a sticky could be useful.

vf

[Fire14]

I also agree this should be a sticky, there is some good information here & I learned something new today from it.
I usually let my batterys go down before charging them, even though I know they don't have the memory effect of Ni-Cads, I thought I was doing something good for the battery.

As for buying spares, I didn't know about the shelf life either & recently bought a spare for my wifes & my Moto's.
Thanks for the post viewfly.

[ian1001]

do these same rules apply to li-polymr(sp?) batteries?

[bobolito]

Originally Posted by viewfly

......... But be careful not to overcharge, unless you know for certain that the charger has turn off protection. The Nokia 6131 manual specifically states not to leave the charger on longer than necessary.

vf

What I question is that in this day and age, are you sure that all phones don't have an overcharge protection as a standard feature? I mean, if the phone is intelligent enough to tell you "Charge Complete" (I haven't seen the first phone that doesn't) how do you know it is still charging the battery? I would think that as soon as the phone says "Charge Complete", the phone will stop the charging flow to the battery, or at least reduce it to a minimum just for the sake of maintaining the battery full. After all, even if powered off, the phone has some control using software over the energy that gets to the battery.

About charging in the morning, I wish I could, but I find it difficult to be able to do that. I have to get to work and my phone takes about 2 hours to charge. I guess I could put it in the USB charger in the computer at work, but I would have to unplug it every time I have to step out of the office and I think that defeats the purpose. The nature of my job requires me to be in and out of the office constantly. After I get home I constantly use my phone. So the only time the phone has a chance to get uninterrupted charge is at night after I go to sleep. At night, my phone still has some 25% of the charge left over.

[viewfly]

Originally Posted by bobolito

What I question is that in this day and age, are you sure that all phones don't have an overcharge protection as a standard feature? I mean, if the phone is intelligent enough to tell you "Charge Complete" (I haven't seen the first phone that doesn't) how do you know it is still charging the battery? I would think that as soon as the phone says "Charge Complete", the phone will stop the charging flow to the battery, or at least reduce it to a minimum just for the sake of maintaining the battery full. After all, even if powered off, the phone has some control using software over the energy that gets to the battery.

A very good question. No, I'm not sure. My Dell computer states that internal electronics prevent overcharging - and not to worry.

My Nokia car charger says the same. P.S. I know that not all car chargers have this function - esp the cheap ones. I took the Nokia apart once, and there is a small pc board inside, and a sense line that is made use of.

My Nokia 6230 manual didn't give any warnings, but the 6131 manual states cleary not to overcharge the phone - implying that the wall charger provided and the phone do not protect for overcharge. On the other hand, Nokia manuals have been incorrect and contradictory in the past (take the example on the 6126 vs 6131 - each manual states a different warning on where not to place the fingers while talking).

So it's is an open question for me - but for now, I will play it safe, and not charge my phone all night long.

P.S. saying 'charge complete' is just stating that the voltage was achieved - it doesn't imply that the phone/charger will prevent overcharging. Certainly my old Nokia wall chargers are just dumb ac/dc transformers.

[viewfly]

Originally Posted by ian1001

do these same rules apply to li-polymr(sp?) batteries?

I don't know for certain about li-polymer - but my guess, from reading the wikipedia information on this li variant, is that the same rules apply. wikipedia does say that li-polymer has a faster aging rate than li-ion (not a good thing), but battery tech changes rapidly. I didn't find anything as specific about li-poly as what is written for li-ion.

[Charlyee]

Originally Posted by viewfly

So it's is an open question for me - but for now, I will play it safe, and not charge my phone all night long.

My 6131 wall charger specifically says "low standby power consumption ". This would lead me to believe that after the phone is charged,the charger goes into a standby mode and some amount of trickle charge is still present.

[viewfly]

Originally Posted by Charlyee

My 6131 wall charger specifically says "low standby power consumption ". This would lead me to believe that after the phone is charged,the charger goes into a standby mode and some amount of trickle charge is still present.

My UK Nokia charger that came with my phone, says nothing like that. Only that is it puts out 5V @350mA. It is made in China.

Maybe your is better than mine. what is the DC output?

P.S. my charger AC-3X has the letters LPS on it. The web page says it is Low standby power, as yours does. I really don't know what that means. I note that none of the other Nokia chargers say that , even the car charger.

[Jay2TheRescue]

Originally Posted by viewfly

My UK Nokia charger that came with my phone, says nothing like that. Only that is it puts out 5V @350mA. It is made in China.

Maybe your is better than mine. what is the DC output?

I know my car chargers all said that they switch to trickle mode when the battery is full. I still use the charger I bought for my V60t 5 years ago on my V551 and my HS820 headsets and have not experienced any bad batteries. (Except on the V60 - that battery was toast when I upgraded.)

-Jay

[viewfly]

Originally Posted by Charlyee

My 6131 wall charger specifically says "low standby power consumption ". This would lead me to believe that after the phone is charged,the charger goes into a standby mode and some amount of trickle charge is still present.

I found this 2006 article in Electronic Design (http://www.elecdesign.com/Articles/I...ID=12195&pg=1).

If the Nokia phone/charger has any intelligence, it should terminate the charge, not continue a trickle charge:

"The continuation of trickle charging isn't recommended for Li-ion batteries. Instead, charge termination is a good option. For NiMH batteries, a timed trickle charge ensures 100% of battery capacity use"

According to the article, the preferred Li-ion charging cycle is:

1) if battery voltage is depleted below 3v, trickle charge until reaches 3V
2) at 3v constant current charge until battery voltage reaches 4.2 V
3) at 4.2 volts, constant voltage charge for a specific time and/or until charging current drawn by the battery reaches some minimum value (normally a couple of hours)
4) Terminate charge - do not trickle.

Now, from what I've read, the phone's probably never lets the battery get to below 3V, so probably there is only stages 2 and 3 happening above.

So, Bobolito, the real question is how smart are the chargers? Do they follow the above? I don't know, but even from Nokia the information is contradictory. One Nokia web page says they use a 'Power Management System' to prevent overcharging (http://www.nokia.ca/english/products...why_nokia.asp).

And I will stand corrected (had a senior moment), the 6230 & 6131 manual say the same thing:

"Unplug the charger from the electrical plug and the device when not in use. Do not leave fully charged battery connected to a charger, since overcharging may shorten its lifetime."

Both of these Nokia statements could just be marketing/legal hype.

Probably the best thing is to have one of my EE friends actually measure the current/voltage used by my Nokia charger during the charging cycle.

Stay tuned. My curiosity is peaked. - But you have to do what is necessary - I've used my phone heavily on travel, and it's all I can do to fall into the hotel bed, and let the phone charge all night. I think the main point, for non-power users, is to charge daily instead of intentionlly running for days to bring it down to shut off - there no real value in doing that.

[Fire14]

Per the Motorola User Manual for the V600 (the closest to my V635) it say's you can leave the charger hooked up after the charge is complete with no problems or damage to the battery. (under Charging the battery)

http://www.motorola.com/mdirect/manu...manual_ENG.pdf

I didn't check any other models yet.

Which is good to know, since the only time I really have to charge my battery is over night while sleeping as well.

[Charlyee]

Originally Posted by viewfly

My UK Nokia charger that came with my phone, says nothing like that. Only that is it puts out 5V @350mA. It is made in China.

Maybe your is better than mine. what is the DC output?

Lol viewfly, no we have the same charger as far as specifications go, the only difference is mine is the AC-3U, which is the US charger and is for all the Nokias that have the mini probe like all the 610X serires, 6126, 6133, 6133.....

Originally Posted by viewfly

......probably the best thing is to have one of my EE friends actually measure the current/voltage used by my Nokia charger during the charging cycle.

Now you did it, I tried to find a clamp on mA meter but working in an environmemt that considers 600 volts low voltage, and 4160 volt, medium voltage that quest proved to be completely futile.

Originally Posted by viewfly

Stay tuned. My curiosity is peaked......I think the main point, for non-power users, is to charge daily instead of intentionlly running for days to bring it down to shut off - there no real value in doing that.

Yes I completely agree and I for one, was certainly guilty of that.

You have my curiosity peaked also, so I did some research by dusting off my text books and some web browsing, here are bits and pieces of information I gathered.

1. Lithium ion polymer batteries, or more commonly lithium polymer batteries (Abbreviated Li-Poly or LiPo) are rechargeable batteries which have technologically evolved from lithium ion batteries. Ultimately, the lithium salt electrolyte is not held in an organic solvent like in the proven lithium ion design, but in a solid polymer composite such as polyacrylonitrile. There are many advantages of this design over the classic lithium ion design, including the fact that the solid polymer electrolyte is not flammable (unlike the organic solvent that the Li-Ion cell uses); thus, these batteries are less hazardous if mistreated.

2. The chemistry is basically the same for the the Lithium Ion & Lithium Polymer batteries, so charging methods should be the same.

3. The lithium ion battery is easy to charge. Charging safely is a more difficult situation. The charge cannot be terminated on a voltage. The capacity reached at 4.2 Volts per cell is only 40 to 70% of full capacity. For this reason you need to continue to charge until the current drops, and to terminate on the low current.

It is important to note that trickle charging is not acceptable for lithium batteries. The Li-ion chemistry cannot accept an overcharge without causing damage to the cell, possibly plating out lithium metal and becoming hazardous.

4. Charge temperature--must not be charged when temperature is lower than 0° C or above 45° C.

5. Lithium Ion, or Li-Ion, uses a different charge algorithm. In this case, a constant current is supplied to the battery until the battery terminal voltage reaches 4.1 volts per cell. The charger then changes to a constant voltage source at 4.1 volts per cell, and the current tapers until it reaches 1/20 of the original constant current. The constant current, referred to as the bulk charge current is nominally set to the battery capacity divided by 2, and expressed in amperes. Assuming that 4.0 is the specified cell voltage.

I also did some research on what "low standby power consumption" means for our Nokia chargers-the most reasonable theory I could relate to is if you leave your phone plugged in for an extended period of time the charger will trickle charge the phone as the phone discharges from just sitting there. So if this is the case then I stand corrected, there is no trickle charge going into the battery after the charge is complete, and/or the battery is fully charged.

I am anxious to hear what data your EE friends come up with.

[viewfly]

Originally Posted by Charlyee

Lol viewfly, no we have the same charger as far as specifications go, the only difference is mine is the AC-3U, which is the US charger and is for all the Nokias that have the mini probe like all the 610X serires, 6126, 6133, 6133.....Now you did it, I tried to find a clamp on mA meter ...

So if this is the case then I stand corrected, there is no trickle charge going into the battery after the charge is complete, and/or the battery is fully charged.

I am anxious to hear what data your EE friends come up with.

I did get your curiousity up! Your info on Li-ion matches well with what I found too. The li-poly info you found confirms that they should be treated the same, regarding charging.

I'm away this weekend, but I'll try my EE next week. It will be a little trick to access the dc wiring without damage, but perhaps I will try on an older transformer first.

Some interesting info in this Thread.

vf