Really?!? - yet another battery rant

[Jerzyiroc]

@Jerzyiroc I didn't quite follow the last part of your post. Are you saying that an aftermarket battery fixed the problem for you?

No the wall charger fixed my problem. Sorry if I wasn't clear. 6mg of Dilaudid @ 5am is not a good mix lol. Charging the original battery on the wall charger has seriously changed my battery life in a huge way. The Evo isn't really bad on battery life at all, hell it's better than my old less powerful and capable Hero. The problem is how the Evo charges the battery. Take that out of the equation by charging the OEM battery on the wall and bam. Sweet ass battery life ftw lol. I intend on only using the extra batter the kit comes with for an emergency and overnight while the OEM battery charges. I'm tellin you its the best 10 bucks Ive ever spent

 

[Jerzyiroc]

That is incorrect.

Once the phone charges to what we read as "100%," the phone does not begin to run off the battery.

What is happening is that as the battery reaches a charge of 4.2 VDC (maximum safe), the phone stops charging the battery as storing a Li+ battery at full charge significantly reduces it's lifespan. The charging circuitry powers the phone and charges the battery in parallel. The phone is not running off the battery alone.

The effect you're seeing is that a Li+ battery cannot maintain a maximum charge for very long. So while the maximum capacity of the battery is 4.2 V, it's nominal voltage is down around 3.8 V. So, without being charged, the battery will slowly discharge on it's own toward a voltage closer to it's nominal voltage. If there was a problem, the discharge wouldn't level off as it does. That 7 - 10% you lose in the first 20 minutes would continue and the battery would die in under two hours.

This is why removing the charge and re-applying it is effective. By removing it and returning it, it resets the charging system within the phone that will allow you to charge the battery back up to max again. As long as you take the phone off the charger when it's at that max point, you're getting the best life of the battery possible. However, if you left it on for another couple hours, it will self-discharge again.

So this is not a defect, it's by design to preserve the battery. The battery percentage reported by various apps is actually somewhat subjective. "100%" can be based on either the absolute maximum charge the battery can hold, which is what all the apps are doing. Or, you can figure the percentage based on the nominal voltage of the battery. So at the max 4.2 V could then be interpreted as close to "120%" of the nominal voltage.

If you want to verify this and have access to a voltmeter, do this: charge the battery to max using the remove/replace charging method. Now, remove the battery from the phone and take a reading; it should be around 4.18 V. Leave the battery out for a couple hours and take a reading again. You'll find that the battery is around 4.0 V. After a couple more hours, you'll find it won't vary much from that.

This is part of the reason that companies use somewhat obscure bars to indicate battery level opposed to a precise measurement. The discharge of a Li+ battery is a bit funky if you don't know about them and can cause panic and confusion if you look to closely.

Sorry but I just can't see that as being a "design" to save the battery. I've owned not only tons of phones but also tons of electronics that run of lithium batteries and they DONT do that. It doesn't let it drain to 3.8 volts after its been charged. The charger is designed to MAINTAIN a full charge. Usually by letting it drop a few hundredths of a volt then bringing it back to a full charge. Not charge it and then if its not taken out at the perfect time then o well lets let it drop to 3.8 volts which btw on the Evo is only about 35-38% of battery power left. If that theory was correct then every lithium charger would do the same and it doesn't. The Evo and Incredible are the only two lithium powered devices I've ever heard or seen let the battery drop while it's on the charger still.

 

[AndroidOne]

That is incorrect.

Once the phone charges to what we read as "100%," the phone does not begin to run off the battery.

What is happening is that as the battery reaches a charge of 4.2 VDC (maximum safe), the phone stops charging the battery as storing a Li+ battery at full charge significantly reduces it's lifespan. The charging circuitry powers the phone and charges the battery in parallel. The phone is not running off the battery alone.

The effect you're seeing is that a Li+ battery cannot maintain a maximum charge for very long. So while the maximum capacity of the battery is 4.2 V, it's nominal voltage is down around 3.8 V. So, without being charged, the battery will slowly discharge on it's own toward a voltage closer to it's nominal voltage. If there was a problem, the discharge wouldn't level off as it does. That 7 - 10% you lose in the first 20 minutes would continue and the battery would die in under two hours.

This is why removing the charge and re-applying it is effective. By removing it and returning it, it resets the charging system within the phone that will allow you to charge the battery back up to max again. As long as you take the phone off the charger when it's at that max point, you're getting the best life of the battery possible. However, if you left it on for another couple hours, it will self-discharge again.

So this is not a defect, it's by design to preserve the battery. The battery percentage reported by various apps is actually somewhat subjective. "100%" can be based on either the absolute maximum charge the battery can hold, which is what all the apps are doing. Or, you can figure the percentage based on the nominal voltage of the battery. So at the max 4.2 V could then be interpreted as close to "120%" of the nominal voltage.

If you want to verify this and have access to a voltmeter, do this: charge the battery to max using the remove/replace charging method. Now, remove the battery from the phone and take a reading; it should be around 4.18 V. Leave the battery out for a couple hours and take a reading again. You'll find that the battery is around 4.0 V. After a couple more hours, you'll find it won't vary much from that.

This is part of the reason that companies use somewhat obscure bars to indicate battery level opposed to a precise measurement. The discharge of a Li+ battery is a bit funky if you don't know about them and can cause panic and confusion if you look to closely.

This is as plausible an explanation as others for the observed behavior of battery charge patterns on the Evo. I am of the opinion that rather than using a voltemeter, a very sensitive amp meter between the charger and the phone will answer the question of how the charging mechanism may be working once the battery reaches 100%.

I also echo the statement from Jerzyiroc, I own multiple electronics with Lithium batteries and do not experience this phonomenon. By phenomenon I do not mean the rapid drop in battery percentage reported after disconnecting the phone from the charger, but rather the vast differences in actual battery charge longevity between described charging procedures.

I have to disagree with your statement that this is a feature of the Evo, this feature seems to be causing most of the charge lasting issues experienced by most users.

 

[Darth Mo]

Sorry but I just can't see that as being a "design" to save the battery. I've owned not only tons of phones but also tons of electronics that run of lithium batteries and they DONT do that. It doesn't let it drain to 3.8 volts after its been charged. The charger is designed to MAINTAIN a full charge. Usually by letting it drop a few hundredths of a volt then bringing it back to a full charge. Not charge it and then if its not taken out at the perfect time then o well lets let it drop to 3.8 volts which btw on the Evo is only about 35-38% of battery power left. If that theory was correct then every lithium charger would do the same and it doesn't. The Evo and Incredible are the only two lithium powered devices I've ever heard or seen let the battery drop while it's on the charger still.

The charger can be designed however the manufacturer sees fit, which is why HTC provides the instructions for getting the battery to maximum charge before taking the phone out for the day. It proves that the battery can be charged to maximum capacity using the phone, but also that it's limited from continuously charging.

"Other" devices are absolutely irrelevant. It is fact that storing a Li+ battery at full charge reduces it's life; there's no debating that. The more times you charge them to maximum capacity also reduces the life of the battery. A manufacturer can choose to continuously charge the battery, however, so every charger does not have to have the limiting properties, but most do from laptops to cordless power tools.

As for 3.8V being 35-38% of the charge for the Evo, that's ow it works. All electronic devices have an operating voltage range outside (both higher and lower) than the nominal voltage of a battery. It's just how they work. AA alkaline batters have a nominal voltage of 1.5V, but a new battery will have a charge of 1.65V. Most devices will operate with a combination of those batteries with their charge between 1.65 - 1.43V. Some are pickier, such as digital cameras where the low threshold is a bit higher which is why your camera might die, but you can throw the batteries in a remote control and it works fine. When batteries are "dead," their voltage is never 0. The voltage has merely dropped outside the operating range of the device.

No offense, but you say you don't know of any other devices that charge this way, but how many have you tested? How many of them have % readouts where you not only care to look closely at it and can quantify how it's actually charging/discharging. This is exactly what a "smart charger" is.

Now, that said, it's possible that for the Incredible and Evo, HTC is allowing the battery to fall further than other devices, but it's still by design nonetheless. It's also possible that the particular has a higher rate of self-discharge.

But your assertion that ALL (or at least that it's the norm) Li+ charging systems constantly charge the battery is absolutely wrong.

 

[AndroidOne]

The charger can be designed however the manufacturer sees fit, which is why HTC provides the instructions for getting the battery to maximum charge before taking the phone out for the day. It proves that the battery can be charged to maximum capacity using the phone, but also that it's limited from continuously charging.

"Other" devices are absolutely irrelevant. It is fact that storing a Li+ battery at full charge reduces it's life; there's no debating that. The more times you charge them to maximum capacity also reduces the life of the battery. A manufacturer can choose to continuously charge the battery, however, so every charger does not have to have the limiting properties, but most do from laptops to cordless power tools.

As for 3.8V being 35-38% of the charge for the Evo, that's ow it works. All electronic devices have an operating voltage range outside (both higher and lower) than the nominal voltage of a battery. It's just how they work. AA alkaline batters have a nominal voltage of 1.5V, but a new battery will have a charge of 1.65V. Most devices will operate with a combination of those batteries with their charge between 1.65 - 1.43V. Some are pickier, such as digital cameras where the low threshold is a bit higher which is why your camera might die, but you can throw the batteries in a remote control and it works fine. When batteries are "dead," their voltage is never 0. The voltage has merely dropped outside the operating range of the device.

No offense, but you say you don't know of any other devices that charge this way, but how many have you tested? How many of them have % readouts where you not only care to look closely at it and can quantify how it's actually charging/discharging. This is exactly what a "smart charger" is.

Now, that said, it's possible that for the Incredible and Evo, HTC is allowing the battery to fall further than other devices, but it's still by design nonetheless. It's also possible that the particular has a higher rate of self-discharge.

But your assertion that ALL (or at least that it's the norm) Li+ charging systems constantly charge the battery is absolutely wrong.

OK, now this makes a lot of sense to me. I wasn't aware (or skipped the section) of HTC charging procedures. Thank you for the information.

I am fairly certain then than topping off the battery daily as I do may affect the overall battery life... and I am perfectly willing to accept risk this in exchange for better day-to-day usability. My question, do you know if operating with a fully charged battery as this may have any detrimental effects on the phone's circuitry?

 

[Jerzyiroc]

I wasn't aware of HTC's charging procedure either. Honestly someone in that place should be kicked in the nuts. Never, NEVER have I heard of a device having to be charged and pulling it off immediately when it hits 100%. That's just flat out stupid in every conceivable way. Does HTC not realize that most people plug their phones in overnight to charge and leave it there? My Hero doesn't do what the Evo does. I can have it plugged in all night and the battery doesn't drop 15% within the first few minutes of it being unplugged. My sister in laws new MyTouch Slide doesn't do it either. They both sit on the charger all night and the battery level's on both drop at a normal rate. Not 1% a minute like the Evo does the first 10-20 minutes. My laptop doesn't do it either. I usually use my laptop right before I go to bed for about 2 hours. So i just leave it in to charge overnight. I've plugged it in to top it off and pulled it almost immediately after going to 100% and I've never noticed a difference in how fast the battery level has dropped. So either it's not a design that HTC put in the Evo and it's a flaw, or HTC tech is filled with a bunch of idiots and somehow think it's a great "design" to have a battery lose 1% of battery life a minute the first 20 minutes or so that you use the phone.

 

[Darth Mo]

OK, now this makes a lot of sense to me. I wasn't aware (or skipped the section) of HTC charging procedures. Thank you for the information.

I am fairly certain then than topping off the battery daily as I do may affect the overall battery life... and I am perfectly willing to accept risk this in exchange for better day-to-day usability. My question, do you know if operating with a fully charged battery as this may have any detrimental effects on the phone's circuitry?

Topping off the battery is not bad, just storing (or constantly charging) it at that voltage would be. But, you have the protection built in, so you're good. Technically each charge/discharge of the battery reduces it's life, but that's just how it is. Batteries aren't meant to last forever.

As far as running it at max voltage, that's fine as well because the phone has a power supply built in to regulate the voltage actually reaching the circuitry.

 

[AndroidOne]

I wasn't aware of HTC's charging procedure either. Honestly someone in that place should be kicked in the nuts. Never, NEVER have I heard of a device having to be charged and pulling it off immediately when it hits 100%. That's just flat out stupid in every conceivable way. Does HTC not realize that most people plug their phones in overnight to charge and leave it there? My Hero doesn't do what the Evo does. I can have it plugged in all night and the battery doesn't drop 15% within the first few minutes of it being unplugged. My sister in laws new MyTouch Slide doesn't do it either. They both sit on the charger all night and the battery level's on both drop at a normal rate. Not 1% a minute like the Evo does the first 10-20 minutes. My laptop doesn't do it either. I usually use my laptop right before I go to bed for about 2 hours. So i just leave it in to charge overnight. I've plugged it in to top it off and pulled it almost immediately after going to 100% and I've never noticed a difference in how fast the battery level has dropped. So either it's not a design that HTC put in the Evo and it's a flaw, or HTC tech is filled with a bunch of idiots and somehow think it's a great "design" to have a battery lose 1% of battery life a minute the first 20 minutes or so that you use the phone.

Feel your pain brother!

Be as it may, we can not change the way the charging system is working. But we can easliy top-off the battery in the morning, just takes an extra 15-30 minutes for me which is fine as I use that time to get ready for work anyway.

With a topped-off battery, life is good again with my Evo...

 

[Jerzyiroc]

Feel your pain brother!

Be as it may, we can not change the way the charging system is working. But we can easliy top-off the battery in the morning, just takes an extra 15-30 minutes for me which is fine as I use that time to get ready for work anyway.

With a topped-off battery, life is good again with my Evo...

Lol it's so damn frustrating. O well. I don't charge the battery thru the Evo anymore. I use the wall charger. I've said it a million times and totally beating a dead horse but that ebay kit is the best $10 i've ever spent lol.

 

[eagle63]

@DarthMo
First, it's clear that you know something about batteries (or if not you're doing a good job of making it up as you go) and I'm certainly not going to pretend that I know anything about the inner workings of battery technology. All I can do is relate my own observations. My previous phone was a Palm Pre. It has a battery meter than reads in 1% increments. I've tested this on my Pre (which I still own), and it doesn't behave this way. When you pull the phone off the charger, it starts at 100% and drops evenly and predictably. Incidentally, I've used my Pre's charger to charge my Evo, but it behaves the same as using the HTC charger.

Whether the Evo's charging behavior is by design or not, isn't really the point. What's most telling about this situation is that lots and lots of Evo owners are noticing this. And they're not noticing it by hooking up voltimeters or even measuring they're battery usage per hour, they're getting to work/school/whatever in the morning and saying, "hey, why the F is my battery meter sitting at 75%? I haven't even used my phone this morning!" In other words, they're noticing it without trying to notice it.
I've owned lots of smartphones and lots of feature phones in my day. I have never seen anything like this before, and I would bet no one else has either. I find it really hard to believe that this isn't a flaw, or at the very least a very lousy design decision.

 

[Darth Mo]

@DarthMo
First, it's clear that you know something about batteries (or if not you're doing a good job of making it up as you go) and I'm certainly not going to pretend that I know anything about the inner workings of battery technology. All I can do is relate my own observations. My previous phone was a Palm Pre. It has a battery meter than reads in 1% increments. I've tested this on my Pre (which I still own), and it doesn't behave this way. When you pull the phone off the charger, it starts at 100% and drops evenly and predictably. Incidentally, I've used my Pre's charger to charge my Evo, but it behaves the same as using the HTC charger.

Which charger (technically it's an adapter) you use is irrelevant. The charging circuitry is actually built into the phone. The thing you plug into the socket is just a transformer and a rectifier that converts the 120VAC provided by your wall socket to 5VDC as needed by the phone. It has no control over how the phone charging circuit will use the provided power.

Whether the Evo's charging behavior is by design or not, isn't really the point. What's most telling about this situation is that lots and lots of Evo owners are noticing this. And they're not noticing it by hooking up voltimeters or even measuring they're battery usage per hour, they're getting to work/school/whatever in the morning and saying, "hey, why the F is my battery meter sitting at 75%? I haven't even used my phone this morning!" In other words, they're noticing it without trying to notice it.
I've owned lots of smartphones and lots of feature phones in my day. I have never seen anything like this before, and I would bet no one else has either. I find it really hard to believe that this isn't a flaw, or at the very least a very lousy design decision.

I acknowledged that it's odd behavior, but also provided the HTC charging procedure which eliminates the issue but also validates it. If you don't like it, that's fine, it is a bit annoying. I was just dispelling the myth that the phone runs off the battery once the charge reaches 100% since that is false.

 

[digink#AC]

So when I leave my phone on the charger all night and I do what the people here say, take it off the charger and wait for the light to turn off then plug it back in. It takes like 1-2 min for it to turn green again and I still get the drop off.. Mine isn't too bad but am I doing something wrong?

Do I need to be powering the phone off?

Thanks

 

[Jerzyiroc]

When you take it off the charger just leave it alone for about 10-15 minutes or so then plug it back in.

 

[eagle63]

Which charger (technically it's an adapter) you use is irrelevant. The charging circuitry is actually built into the phone. The thing you plug into the socket is just a transformer and a rectifier that converts the 120VAC provided by your wall socket to 5VDC as needed by the phone. It has no control over how the phone charging circuit will use the provided power.

Makes sense. So this charging circuitry is in the phone, not the battery itself? (so trying an aftermarket battery won't make any difference) I assume then it's also not part of the firmware? (not fixable or modifiable)

I acknowledged that it's odd behavior, but also provided the HTC charging procedure which eliminates the issue but also validates it. If you don't like it, that's fine, it is a bit annoying. I was just dispelling the myth that the phone runs off the battery once the charge reaches 100% since that is false.

Yep, understood. Count me firmly in the camp that thinks this is a defect on HTC's part, as I can't think of any logical reason why the Evo would behave differently in this regard compared to other devices. (it's not like charging Lithium batteries is a brand new concept that needed an engineering re-think).

 

[DizWhiz]

I agree with others here that if you plugged in your EVO to charge overnight, unplug it, and then plug it back in to charge again. Mine turns orange and about 3-5min later it goes green again.

If I do this my battery doesn't drop below 85% until I hit around the 5hr mark.