After a full charge, unplugging causes it to drop battery %?

[Fullstop]

Thanks! Very informative. I read.in the comments about not letting it drop below 5%, but there is no explination. Is it detrimental to let it do this?

Obviously results may vary. I'm getting a bit better chunk of life than Slinky, but I now understand it more. I think I will obtain as much data as I can and see what happens.

Thank you!

Sent from my ADR6400L using DroidForums App

 

[Snow02]

Consistently letting it die will decrease the useful life of the battery.

 

[BigMcGuire]

Ok, here is what I see. The battery indicator is wrong and yes, it does lose charge while plugged in especially over long periods of time.

Using the HTC Battery Widget - I noticed that the Voltage gets to about 4211 mV when fully charged at 100%. However, if I leave the phone plugged in all night and wake up to a 100% charged green led phone -- I'll notice that the Widget says my Voltage is 3800 mV and very quickly after unplugging I'll go to 90% within a few minutes.

Using the bump charge and watching the voltage, I can make sure it gets to 4200+ mV and thus retain 100% charge longer, but seems to me to be kind of pointless especially when I leave for work immediately after I wake up in the mornings.

Another observation: If I unplug the phone, and use it for a bit, get it to 90% battery life, I'll see that the Voltage is 3800 mV, plug it in, and it will get to 4197 mV pretty quickly, but over the next hour, the % will go from 90-100% even though the voltage stays around 4190~ mV.

This seems to me to be a pretty serious flaw in the way HTC charges their batteries. But at least now I know what's going on. Maybe this helps battery life instead of constantly charging/uncharging/charging to keep a phone at 100% while it is plugged in? At least that's what I've read.

 

[slinky]

Update - 5 hours, battery drained 90%, doing nothing but standby and has k9 email running in the background. Same setup as my Incredible which lasted much longer. Obviously something is wrong, will take it in and update you when I know something.

 

[Snow02]

@Big Voltage will always show > 4 V while charging. This is because the voltage has to be higher than the battery's nominal voltage to charge. What you're witnessing with the battery showing ~3.8 V after having been on the charger all night is the phone having stopped charging, and letting the battery settle to its designed voltage (3.7V).

This is by design, as keeping the voltage over 4V for long periods of time will destroy your battery's ability to hold a charge rather quickly. This is also why bump charging before taking it off the charger can give you a little more life.

 

[BigMcGuire]

Update - 5 hours, battery drained 90%, doing nothing but standby and has k9 email running in the background. Same setup as my Incredible which lasted much longer. Obviously something is wrong, will take it in and update you when I know something.

What I'm finding is, the battery meter is incorrect. It is not reliable. You need to do a test where you go from full to completely drained. You'll find that from 100-80% it will drop fast, from 80-15% it will be really slow. I did a test yesterday where I tried to drain my battery, calling, taking HD video and uploading to youtube, etc... Only took 1.5 hours to get to 80% but it took 10+ hours to get to 20%.

The way this phone reads battery is quite deceiving. You'd think that the HTC developers would realize this, and like the automobile industry, make it stay at Full longer even if it isn't entirely accurate. I mean seriously.... Anyone with a brain on their head will know that a 4g device, with this screen, on a 1400mAh battery...... battery is going to be a serious issue.

 

[BigMcGuire]

@Big Voltage will always show > 4 V while charging. This is because the voltage has to be higher than the battery's nominal voltage to charge. What you're witnessing with the battery showing ~3.8 V after having been on the charger all night is the phone having stopped charging, and letting the battery settle to its designed voltage (3.7V).

This is by design, as keeping the voltage over 4V for long periods of time will destroy your battery's ability to hold a charge rather quickly. This is also why bump charging before taking it off the charger can give you a little more life.

Thanks for the info. I am no electrical engineer. So the voltage doesn't have anything (really) to do with battery %, at least not directly. I figured they were synonymous.

 

[Snow02]

What I'm finding is, the battery meter is incorrect. It is not reliable. You need to do a test where you go from full to completely drained. You'll find that from 100-80% it will drop fast, from 80-15% it will be really slow.

Also normal.

 

[Snow02]

Thanks for the info. I am no electrical engineer. So the voltage doesn't have anything (really) to do with battery %, at least not directly. I figured they were synonymous.

Voltage is absolutely an indicator of charge.

 

[BigMcGuire]

Many thanks for that graph, clears a lot of things up. Interesting.

So because my OG Droid lasted forever at 90% and went quickly down after that, it maybe that the battery reader may be less accurate than the HTC Thunderbolt. And the Thunderbolt's battery reader may be very accurate and we're all used to inaccurate battery %s.

 

[Snow02]

Heh. No problem. It's always nice when you can see a an illustration that exactly describes what you're experiencing.

 

[Snow02]

So because my OG Droid lasted forever at 90% and went quickly down after that, it maybe that the battery reader may be less accurate than the HTC Thunderbolt. And the Thunderbolt's battery reader may be very accurate and we're all used to inaccurate battery %s.

Actually, I would bet that the larger drain from the thunderbolt makes that steeper initial discharge slope a little more pronounced.

 

[funkyb]

Apologies if this has already been posted...just saw the OP title and dove in headfirst:

Your battery gauge is lying to you (and it's not such a bad thing)

 

[Snow02]

Thanks for the link. It corroborates what I thought.

 

[EdForsythe]

I've posted this before, but this is why you're seeing the immediate drop:

Your battery gauge is lying to you (and it's not such a bad thing) - xda-developers

Also, if you want to bump-charge, you should charge until the light turns green, pull the battery, put it back in, then plug the phone back in, wait until it's green again, then turn the phone on.

Is that what's called a bump charge? I've never heard the term in all of my many years until I saw it used on these forums. I'm guessing you remove and replace the battery to insure a cold boot? BTW, here's what Seidio says about charging their batteries:
"In order to obtain the full capacity of your Seidio battery, we highly recommend that you leave the battery/your phone on the charger for an additional 2-3 hours after the charging indicator turns green or the battery status shows full." That's news to me also.