This is why your battery drops 10-15% in the first 20 minutes.

[Jesse]

Jesse, thanks for doing this research. It's definitely disheartening that the EVO doesn't run off AC once it's fully charged.

Last night, I turned my Evo off to charge it. When I turned it back on this morning, it dropped to 93% in about 10 minutes. So there's probably more to this story. But thanks for writing the first chapter!

I'm sure it reverts back to AC power at some point, but the Evo definitely runs off DC once it's fully charged. I'm curious to see how long it will run off the battery before it draws more power.

 

[xorbe]

I officially contest the first post in this thread:

Soon after Battery Indicator was reporting a 100% charge, the Kill A Watt also reported a draw of 0.00. Meaning the Evo was not drawing any electricity whatsoever, indicating that it was in fact running off its battery. Even when I turned the screen on, maxed out the brightness, and ran Linpack, the Kill A Watt reported no electrical draw.

0.01A is 1.2W ... the Evo uses FAR less when just sitting there. Your tool is insufficient! An idle Evo should use about 0.19W or 0.0015 amps as reported from the 120V Kill-A-Watt meter -- that item isn't for measuring such small amounts. Results are definitely in the noise region. It's like weighing a mouse with an elephant scale ...

Let me try measuring tonight ... I have fancy R/C tools for this (from my lithium-powered model jets and airplanes hobby.)

I have a TON of spare USB cables now ... I'll splice one and get on the DC side.
Also, maybe I can figure out a way to get between the battery and the phone without soldering wires.

 

[Robbie317]

Plain and simple: When the Evo is fully charged, it begins running off its battery until you plug it back in. It DOES NOT trickle charge whatsoever after it reaches 100%. When you're using your Evo on the charger, and it's showing full 100% charge, it is running off the battery, not the AC plug. And then when you unplug it, well, we all know what happens next. The battery meter drops insanely fast to the actual charge of the battery, which could be very low, depending on how long it's been sitting idle at 100% on your charger.

So all those times you've charged your Evo overnight, only to take it to work the next day and be at 80% within an hour? Your Evo was running off its battery for what I'm guessing was most of the night. It takes my Evo about an hour to two hours to fully charge back to 100%. Let's say you put your Evo on the charger at 11PM, it'll reach full charge by 1AM at the latest, and then run off its battery until whenever you take it off the charger in the morning.

Workarounds?

1) Turn your Evo off while it's charging.
2) If you must leave it on for an alarm clock, put it in airplane mode and end all CPU intensive tasks to minimize battery drain.
3) When you wake up, unplug it for 10-20 minutes (still experimenting with this number), and then plug it back in to top it off. Once it reaches 100%, take it off the charger, and go about your day.

Try it out for yourself. When your Evo is 100% charged, take it off the charger immediately, and I highly doubt you will lose the 10%-15% within minutes. Please share your findings.

UPDATED 6-18-10​

So to help prove my theory, I've plugged my Evo into a Kill A Watt, and charged it to 100%. For those who don't know what a Kill A Watt is, it's a device you plug into your wall, and then plug your electronics into it, and it will tell you exactly how much electricity they're drawing. Coupled with the Battery Indicator app, I took readings on how much electricity my Evo was drawing as it charged.

I started charging at 78%, and it was drawing 0.08 amps until it reached 90%. At 90%, it began drawing less and less, until around 50%, at which point it was drawing only 0.04 amps. It stayed steady at 0.04 amps until it reached 100%. Soon after Battery Indicator was reporting a 100% charge, the Kill A Watt also reported a draw of 0.00. Meaning the Evo was not drawing any electricity whatsoever, indicating that it was in fact running off its battery. Even when I turned the screen on, maxed out the brightness, and ran Linpack, the Kill A Watt reported no electrical draw.

I kept my Evo plugged in for 15 more minutes, all while Battery Indicator reported a 100% charge, however, the Kill A Watt remained at a dead 0.00 draw. This doesn't necessarily mean that the Evo doesn't trickle charge, but it does mean it runs off its battery once it reaches a 100% charge. I have a feeling once the battery drops to a certain percentage (although still displaying a 100% charge), it will draw electricity until it reaches 100% again.

Still a bit more testing to do. Will be back with results.

I fully disagree with this post and insight... I always charge my EVO over night and I do not put it in airplane mode or turn it off.... The 100% - 0% battery life is misleading in a lot of ways. I keep mine charged next to the bed at night.... Perfect example of why I disagree with this... I got up last Saturday morning and went down to get the coffee started. My phone had been on the charger from 11 at night and when I got up it was 7:45 in the morning... I got the coffee started let the dogs out and jumped on my computer in my office.... All the while I thought my EVO was still on the charger... Coffee was done and I went back down to get me a cup.... I go back up to my office and back on the computer.. probably 15 - 20 minutes later I went to see if the wife was up... Low and behold my 7 year old daughter was laying on my bed next to the wife... She had unplugged the EVO from the charger and was laying their watching video on You Tube. I didn't mess with her and left her alone with it and just told her she needed to ask before playing with my phone.... another 20 - 30 minutes went by and I took my phone back.... She had at least been using the phone for a minimum of 40 minutes watching video on You Tube..... I checked the battery meter and it still had all 10 squares green.. I looked in another app and my battery life read 97% and when I checked it again an hour later is read 92%.....

From "RED" to fully charged takes my phone about 2 hours.... So that would mean it stopped charging and using A/C power around 1 or 2 in the morning and then it started to pull from the battery... Which it obviously didn't....

Plus in the two weeks I have now had my EVO and reading about battery life I check my battery meter more often than I really should.. Only 2 - 3 times in the 14 days I have had the EVO has the battery life dropped for what I would consider a "Dramatic" amount in the first 30 minutes to an hour... All other times it does not drop much.... and always less than 10% in the first hour and this includes checking all the e-mails that popped in over night and a little web time at breakfast....

Now the phone COULD revert to battery at fully charged and then starts charging again when the battery falls below 80% and my daughter just happened to pull it off while it was literally at 100% and fully charged.... but I have not had the dramatic drops in the first hour as a lot of people are reporting....

 

[Jesse]

I officially contest the first post in this thread:



0.01A is 1.2W ... the Evo uses FAR less when just sitting there. Your tool is insufficient! An idle Evo should use about 0.19W or 0.0015 amps as reported from the 120V Kill-A-Watt meter -- that item isn't for measuring such small amounts. Results are definitely in the noise region. It's like weighing a mouse with an elephant scale ...

Let me try measuring tonight ... I have fancy R/C tools for this (from my lithium-powered model jets and airplanes hobby.)

I have a TON of spare USB cables now ... I'll splice one and get on the DC side.
Also, maybe I can figure out a way to get between the battery and the phone without soldering wires.

You might be right there, but even so, when the Evo is charging, and I run Linpack or do any CPU intensive tasks, the Kill A Watt jumps up to 4.5 watts of usage. But once it's 100% fully charged and I do the same tasks or run Linkpack, the Kill A Watt maintains a 0 reading.

 

[Jesse]

@ Robbie. My battery life lasts me an entire day with no problem. I'm more or less just trying to figure out why sometimes the battery drops 10% in 5 minutes, and other times it stays there for an hour with the exact same use.

 

[xorbe]

I'm splicing USB wires now, but my battery is couple hours from full charge. (Ran a battery drain test.)

edit: Okay, my 5 volt mA measuring setup is ready, but I was really hoping to run my battery down to 3.2 volts for my current battery test first ... but it's taking longer than expected, oh the irony. ^_^

 

[PainKiller]

When I say the circuitry, I mean the actual hardware that is directly monitoring the battery itself, not the software running on the phone.

I am more inclined to believe its the first one. I would like to know if the same problem with battery drop exists on other HTC phones. Since the batteries are interchangable with other HTC phones I would like to charge my battery in one of those devices or use a battery that was charged in one in my phone and see if I experience

After having the exact same issues as you with my Eris, I woul say it may be an HTC thing.



~ Transmitted via Motorola Droid 2.1 ~

 

[Robbie317]

@ Robbie. My battery life lasts me an entire day with no problem. I'm more or less just trying to figure out why sometimes the battery drops 10% in 5 minutes, and other times it stays there for an hour with the exact same use.

Like I said mine does not always drop 10% in 5 minutes... After an hour and with my daughter streaming You Tube video for at least 20 - 30 minutes after pulling off the charger I was still over 92% and the battery meter was still 10 full green blocks...

That being said at least twice it has dropped 10% in the first 1/2 hour of pulling it off the charger but reading these threads I have paid closer attention to see if I have the same issue and for the most part I do not. One time with extremely light use 4 hours after pulling it off an all night charge (with nothing turned off and no airplane mode and powered up) I still read over 90%....

I think the battery readings are just awkward.. I got all the way down to 20% and wanted to run it flat dead so I turned the 4G radio on (I don't have 4G in my area) and loaded up Sprint TV's ESPN mobile and it took nearly 2 full hours to kill my battery....

It does seem to drop faster from 100 - 50% but then it seems to take longer to drop from 50% to dead........ it's not an equal drop off... Just how lithium batteries work....

 

[xorbe]

I think the battery readings are just awkward.. I got all the way down to 20% and wanted to run it flat dead so I turned the 4G radio on (I don't have 4G in my area) and loaded up Sprint TV's ESPN mobile and it took nearly 2 full hours to kill my battery....

It does seem to drop faster from 100 - 50% but then it seems to take longer to drop from 50% to dead........ it's not an equal drop off... Just how lithium batteries work....

Yeah, I'm doing a battery test now, and I'm stuck at 25% 3.685 volts, with 100% brightness and 100% volume Pandora ... the phone has already been running Meebo IM client for 7.5 hours (keeps phone awake no sleeping). It's not dying very fast.

 

[Robbie317]

Yeah, I'm doing a battery test now, and I'm stuck at 25% 3.685 volts, with 100% brightness and 100% volume Pandora ... the phone has already been running Meebo IM client for 7.5 hours (keeps phone awake no sleeping). It's not dying very fast.

Always interested to see what your results are...

It seems like it's a heck of a lot harder to kill it once it drops below 40% than from 100 down to that 40%. Lithium Batteries are weird like that.. They have no memory so you can charge them any time you want. But I don't think the OS has a perfect way of reading the battery life.... It's like it THINKS it's eating up battery fast early and then late it has to compensate and then it takes longer to kill late....

 

[Eazy123]

I ran a little battery test yesterday, and at around hours 7-10, it was only dropping 1% per hour.

However, the first hour it dropped 6%. This is not because it was sucking a lot of juice -- it's because lithiums cannot be linearly charted. I gave up after 10 hours because it was headed towards 38+ hours.

ie, the moral of the story is, don't extrapolate from 20 minutes worth of data.

(Today I'm running a test with Meebo IM client running, which keeps the phone awake ... as all Android IM clients seem to do.)

Yeah, below 94 percent, I get about a 1 to 2 percent drain per hour. So all is good, I guess.

 

[apollooff320]

I just think it's retarded how my battery last a lot longer when I don't have a SD card in.

 

[Robbie317]

I checked again... Put my phone on the charger at 11:00 last night... Pulled it off the charger at 9:00 this morning.. Did NOT power the phone off while it charged, NO airplane mode..... Only things that were turned off were 4G radio, GPS and WiFi (which I leave off at all times unless needed any way) Once off the charger I checked and deleted the e-mails/junk that came in over night and pulled up ESPN.com to check some scores. by 10:00 my battery was still at 97% and it's now 11:40 and I am reading 93%......

No clue what is making "Some" phones drops 10% or more in just a few minutes after pulling it off the charger...

 

[nmelkon1]

When I say the circuitry, I mean the actual hardware that is directly monitoring the battery itself, not the software running on the phone.

I am more inclined to believe its the first one. I would like to know if the same problem with battery drop exists on other HTC phones. Since the batteries are interchangable with other HTC phones I would like to charge my battery in one of those devices or use a battery that was charged in one in my phone and see if I experience the same phenomenon.

Food for thought.

Also I wonder if a dedicated battery charger works any differently for these batteries / phones. Don't know if I would want to remove my battery every day or couple days and have to pop that back cover off, it already looks fragile enough as it is.

Lmao you guys treat this phone like a baby with a danty flower. Be a real man and pop that sucker open,throw it in your pocket with your keys and change, hold it in your mouth when your hands are tied like a man!

Message created via myManlyhands for evo4g.

 

[AldousSnow]

I've never held anything in my mouth while my hands are tied. Never been man enough i guess

 

[Robbie317]

Lmao you guys treat this phone like a baby with a danty flower. Be a real man and pop that sucker open,throw it in your pocket with your keys and change, hold it in your mouth when your hands are tied like a man!

Message created via myManlyhands for evo4g.

Hilarious...

Well I don't like the way the back cover pops on and off but I do have a spare battery and I am not at all scared to pop it on and off....

I do try to avoid throwing it in the pocket with my change and keys... I don't use a case (never liked cases, never used one on a phone for more than day) but a screen protector is good enough for me. I don't mind if the case gets a little banged up here and there...

The hold it in your mouth while your hands are tied comment? I think I am confused.. I have never had my hands tied up... Unless your saying you have the phone in your hand and your pockets are full and you got some thing in another hand and need to get your key out your pocket to open the house/car... Been there done that....

 

[nmelkon1]

The hold it in your mouth while your hands are tied comment? I think I am confused.. I have never had my hands tied up... Unless your saying you have the phone in your hand and your pockets are full and you got some thing in another hand and need to get your key out your pocket to open the house/car... Been there done that....

Precisely

 

[Robbie317]

Precisely

Oh and I don't do cases either... Never have been a fan of the case.. It's a phone.. Yeah it's an expensive phone but other than a zagg skin I expect my phones to get a little banged up here and there. Just part of it.. I don't go throwing it across the room or sliding it across tables or the floor but I don't worry too much about it getting dinged up here and there.....

 

[nmelkon1]

More ding and scratchers the merrier, just go into sprint store and blame the build quality, get a replacement for free

 

[godsidekurt]

I just wanna say this guys claim is BS...I tried his idea of turning off the phone while charging overnight and still lost 15% battery within the first half-an-hour of taking it off the charger. This is really annoying and I hope an update fixes it soon.