Battery myths. It is OK to leave your phone plugged in over night.

Rukbat

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IF you leave it at 100% on charge for a LONG time, it will wear the battery a bit over a long time.
Wrong. Once it reaches 100% it stops charging.

IF you leave it closer to 50% it will last longer.
Wrong. If you're going to store it for long period out of the phone, 40% is about the optimal charge, because the self-discharge rate will be lower. You're mixing two totally different things.

BUT, when using the battery, you are wearing it out.
No, you're using it. A well-maintained lithium battery can last so long the phone it's in becomes unusable. (My V551 OEM batteries - over 10 years old - still give me about 95% capacity. They're about 20 years from being "worn out" and, at 72, I don't think I'll be alive by then - and GSM phones probably won't be used any more. [My StarTAC is still the best phone I ever had, probably the best one ever made, but you can't use one any more. No GPS.] Maybe in 20 years, phones will have to have something in them that we haven't even invented yet.)

In other words, if it is unplugged and near 50% you are wearing it out. So the only way to get long battery life is to pull it from the phone at 50% and store it. Impractical.
That's not long life, that's long storage. You still have to check the SoC every 3 months or so to keep it at 40%. Leave it for 5 years and you have a piece of hazardous waste, not a battery. (Lithium is a hazardous material.)

I have always plugged mine in if I am near a charger
Also not the longest life scenario. Charging the battery every time it drops to 90% will give you less total power over the life of the battery than charging it at 40%. (Carrying a spare battery - with a phone with a replaceable battery - is the easiest way to get the most out of your batteries. 40%? No charging capability? Swap batteries.)

See the second figure (the chart) at Battery University - How to Prolong Lithium-based Batteries. Cadex has probably analyzed more batteries in 2014 than all of us combined on this forum have owned over our entire lives. What they don't know about batteries isn't known, it's still being researched (like how to prevent dendrites in lithium batteries - no one knows how to do that yet). If you want the expert word, take it from the experts.

Tabish, my only argument with your original post is that modern batteries (manganese cobalt oxide positive poles and graphite negative poles) have a nominal voltage of 3.7 Volts, but they have a potential of 4.2 Volts while being charged, not "when fully charged". (As soon as you disconnect the charger, the terminal under load voltage drops to 3.7 Volts.) A lot of manufacturers currently charge their batteries to 3.85 Volts terminal voltage by holding them at 4.35 Volts during charging, but that shortens the life of the battery (while giving a slightly longer time between charges). Marketing has a lot of knowledgeless input to engineering these days. When the marketing VP says "this will sell more phones" and the engineering VP says "this will destroy more batteries", marketing wins out. Batteries that die after 6 months don't impact on the company's bottom line, selling more phones does.

No one has invented a new sub-atomic physics yet - manganese cobalt oxide as a positive pole and graphite as a negative pole still gives the same voltage it would have given 10,000 years ago. What we need isn't futzing with existing technology, what we need is a light, power-dense battery that can take constant full discharges, and fast charges. A car battery is still FAR better than ANY lithium chemistry - except for weight. Lithium is the lightest metal, lead isn't. But they're working on it. There's an industry that's bigger than the cellphone industry that's screaming for power-dense, deep-discharge light batteries - the automotive industry. And they'r driving most of the research. A dendrite in the battery of a hybrid or electric car costs the company US$2,000. Put that huge, heavy battery into a box the size of shoe box and we'll see phones with 2 month standby/2 day talk battery times.
 

scassel

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You missed the point entirely ! It cannot overcharge. There is a cutoff once it hits a certain threshold (about 4.35v). The warning is not a warning. It's just a reminder that it is done charging.

I agree wholeheartedly. I chose my words poorly.

Posted via the Android Central App
 

Tabish Syed

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Tabish, my only argument with your original post is that modern batteries (manganese cobalt oxide positive poles and graphite negative poles) have a nominal voltage of 3.7 Volts, but they have a potential of 4.2 Volts while being charged, not "when fully charged". (As soon as you disconnect the charger, the terminal under load voltage drops to 3.7 Volts.) A lot of manufacturers currently charge their batteries to 3.85 Volts terminal voltage by holding them at 4.35 Volts during charging, but that shortens the life of the battery (while giving a slightly longer time between charges). Marketing has a lot of knowledgeless input to engineering these days. When the marketing VP says "this will sell more phones" and the engineering VP says "this will destroy more batteries", marketing wins out. Batteries that die after 6 months don't impact on the company's bottom line, selling more phones does.

No one has invented a new sub-atomic physics yet - manganese cobalt oxide as a positive pole and graphite as a negative pole still gives the same voltage it would have given 10,000 years ago. What we need isn't futzing with existing technology, what we need is a light, power-dense battery that can take constant full discharges, and fast charges. A car battery is still FAR better than ANY lithium chemistry - except for weight. Lithium is the lightest metal, lead isn't. But they're working on it. There's an industry that's bigger than the cellphone industry that's screaming for power-dense, deep-discharge light batteries - the automotive industry. And they'r driving most of the research. A dendrite in the battery of a hybrid or electric car costs the company US$2,000. Put that huge, heavy battery into a box the size of shoe box and we'll see phones with 2 month standby/2 day talk battery times.

That is not how it works! The cell keeps it's voltage at 4.2 or 4.35 (or whatever the charger stops at) even after charging is done.

The voltage holds until a load is applied. The voltage drop is proportional to the load. Better batteries (for example with lower internal resistance) have a lower voltage sag under load. If the load is minor, the voltage sag will be minimal.

I am not saying that physics has changed, but there have been advancements made and newer LiCo batteries are rated at 3.85 / 4.35 V instead of 3.7 / 4.2. This isn't just marketing. If you try to charge an older 4.2v lithium battery to 4.35, you will end up damaging it but newer cells are designed for this voltage. If what you said about marketing was true, then Samsung, Apple etc would be overcharging their lithium batteries which is not only stupid because it lowers battery life but also dangerous.

PS: I just tested my Note 4. Battey at 100%, 4.3V. After removing the charger and with the battery under load and the phone at max brightness.....still 4.3V. After a while, 4.2V.

If I used a cheap crappy chinese battery with a stupid high internal resistance, then the voltage would drop even more.

EDIT: You might be confused about the voltage sag. If so, look up Constant Current / Constant Voltage (CC CV) charging which is commonly used in charging lithium batteries.

This is different than constant current charging (I think car batteries are charged that way). Instead of a constant current then off, CC CV lowers the current gradually until charging current hits 0 at Vmax.
 

ChemMan

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Does anyone have some real numbers to back up anything they are saying here?

Get a data logger and plug the phone in with a dead battery and charge it up and draw the data points.

I had actually done this manually and the results are in the table attached. I really don't think anyone needs to worry about leaving the phone plugged in even after the phone tells you to unplug the charger. The battery life is not going to change "very much" by leaving it plugged in overnight. It is a $30 battery and an $800 phone, think about it from the correct prospective. See attachment #2 for my professional opinion as a communications and electronics expert. Trust me, it will be fine.

!charg note (1).jpg

calm2.png

ps. Sub-Atomic physics aside, We can probably stick with standard old fashioned atomic physics here, No quarks are damaged in the charging of the Note 4. That I am sure of.

lol
 

thomasv23

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I always leave my phone plugged in over-night so I can have a full charge for the whole day and what not and I never ever have battery life issues
 

Barley Singer

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It could also be differences in the number of widgets (and apps) she has up & running all the time, as well as differences in any power/battery conservation programs you might have, that she does not have. My PIPO M6 PRO battery life was utter crap. It got *some* better after I turned off : sound, GPS & cell while at home (most of the time - it is a plablet), and also made the screen turn off after 1 minute without use.

I still did not like the battery drain, so I installed "DU Battery Saver" and suddenly I had a lot more battery time. IMHO the only way they could make that program better would be to add in NFC, so it would automatically adjust the power settings, based on where I am.
 

Bordcla

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Jesus, you have no clue what you are talking about and blatantly misleading people here.

You completely ignore the laboratory test results with real, precise measurements, and based your false statement on your own " Research, experience with Hobby grade Li-Ion and Li-Po batteries/chargers. "? Jee, with your method, who need science?

Would you be so kind as to light our lanterns and share links to what science actually has to say on the issue?
 

natehoy

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It is SAFE to leave your battery plugged in as long as you want. Days? Weeks? Months? Sure. Overvoltage circuitry built into the battery will prevent anything bad from happening. The "your battery is charged, please unplug" message is an energy-conserving one, not a safety message. 90% of the laptops here at work stay tethered to a desk 100% of the time, and after 2-3 years of being plugged in continuously the batteries still work. At somewhat diminished capacity, since they have been abused by being kept at 100% for years, but they work. None have exploded. Few need actual replacement, and most probably would have needed replacement under normal daily use anyway.

Any charge patterns you employ will affect the longevity, good or bad, of the battery long-term. The optimal charge pattern is highly dependent on which specific Lithium technology is used (Lithium Manganese, LIFEPO4, etc etc) and they are all different - which is the root of a lot of the confusion surrounding the care and feeding of "Lithium" batteries - they just ain't all the same. But the net result is that the damage is in the form of a slow, long-term loss in battery capacity, even with the most "abusive" recharge cycles.

The only way to TRULY kill your battery (without physical modifications to the battery) is to discharge it to the point where the phone shuts down, then let it sit in a drawer for a few months while the BMS finally uses up the trickle charge it needs and the cells silently die. Or charge it while applying a lot of heat so it goes into thermal shutdown.

Enjoy your phone. Charge it using a pattern that is convenient to you. When the battery doesn't carry the capacity you need, which will be well over a year or three down the road even in the least optimal recharge patterns for your tech, drop 20-25 bucks for a replacement and continue enjoying your phone.

If you have a phone with a built-in battery, they are generally expensive and difficult to replace. In that case, if you want to keep it for more than three years or so you'll probably want to research the specific Lithium tech used and look up the specifics of managing that battery type, or accept that in three years you'll probably have "wasted" some battery capacity in addition to what was lost due to normal wear-and-tear.

For the Note 4, just order a new battery in a couple of years. Problem solved.
 
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LaTuFu

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I'm not going to dispute the points you've posted and really appreciate the time you've spent to help others, but the one time I did leave my note 4 connected to the fast charger overnight I got a notification to disconnect the phone...something to the effect of "battery at 100% disconnect from charger". I have not seen this when connected to my laptop or desktop. I don't think my phone will explode but isn't this some warning from Samsung related to their batteries, perhaps?

Since then I prefer to charge my phone in the morning as I get ready to leave. It charges up full quickly and doesn't stay on the fast charger past an hour at most.

Posted via the Android Central App

Every Samsung phone I've ever had tells you to unplug when the phone reaches 100% charge. It doesn't "hurt" the long term performance of the battery to leave it plugged in.

I have the same background and experience with LiPo batteries that OP does, and have been saying identical things about batteries in this forum for quite a while.

I'm on my 5th Samsung device, and countless other smartphones/electronic devices with LiPo battery chemistries. Leaving them plugged in will not put you at additional risk. The batteries are built with protection circuits in place to prevent these kind of problems.
 

LaTuFu

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Jesus, you have no clue what you are talking about and blatantly misleading people here.

You completely ignore the laboratory test results with real, precise measurements, and based your false statement on your own " Research, experience with Hobby grade Li-Ion and Li-Po batteries/chargers. "? Jee, with your method, who need science?

On the contrary, the lab results and research I've read supports exactly what OP has stated.

In addition to my own hands on experience with multi-meters and batteries on similar equipment.

We're talking simple voltage and current flow here. It's not nuclear physics.
 

barrettdaniel

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The intergalactic rule of sub atomic physics and bio metric laws of algarithms in super microbiology battery technology.......just charge your phone as you want. If the battery dies after 2 years, you're probably buying a new phone by then anyway, if you haven't already! If not, buy a battery for like 15 bucks on amazon! I have no idea why there is so much arguing over such an insignificant issue.
 

ChemMan

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Yea, what he said

The intergalactic rule of sub atomic physics and bio metric laws of algarithms in super microbiology battery technology.......just charge your phone as you want. If the battery dies after 2 years, you're probably buying a new phone by then anyway, if you haven't already! If not, buy a battery for like 15 bucks on amazon! I have no idea why there is so much arguing over such an insignificant issue.
 

rong21

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I read in a few blogs that leaving your phone plugged in all night causes obesity, hair loss and possibly lactate intolerance...................
 

Haalcyon

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I, like many, have left my batteries charging overnight. To no perceivable I'll effect. I'm sure millions, upon millions do the same thing. With a device with removable batteries, the longevity of a ~$50 part is just not even worth thinking about. I've had plenty of devices with sealed batteries and never had any performance/longevity issues with those batteries either.

IME, contemporary phone batteries provide plenty of longevity. Is this really an issue for others?

🔋from the Note 4✒ 📒
 

natehoy

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IME, contemporary phone batteries provide plenty of longevity. Is this really an issue for others?

It depends, as you accurately pointed out in your previous paragraph, on the ability to replace the batteries. You should see how heated these discussions can get on the Moto X forums, where a dead battery means a VERY expensive paperweight. ;)
 

Haalcyon

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It depends, as you accurately pointed out in your previous paragraph, on the ability to replace the batteries. You should see how heated these discussions can get on the Moto X forums, where a dead battery means a VERY expensive paperweight. ;)
It is one of the reasons I've preferred removable batteries. It means I can rest assured it's not gonna be an issue. I know most don't go through phones like I do but I really feel like it's not going to be a problem in the lifetime of most people's phones (1.5-2 years).

🔋from the Note 4✒ 📒
 

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