Phone battery reading 85% at 4.2v??

[MarioJP]

I don't know what is going on here, but seems like the battery on my phone is being weird. I also notice strange charging/discharging behavior as well. For instance when the battery reaches at 20%, phone just dies without any warning. I pull the battery out, wait for a min or 2, put battery back and now the battery is at 2%???.

When charging, sometimes the percentage randomly jumps and when reached 80%-85% the voltage is 4200mV, and eventually does one big jump from 80% to 99%. That is after the phone has been charging for a good while for that to happen.

So with that being said, what is going on here??.

 

[mdh1979]

Hey Mario,

What brand and model of phone is it and how old is the battery?

Matt

 

[Aquanaut]

I can't really say what's going on, but for my laptop and my GPS unit, both with Li-ion batteries, their manuals say to fully discharge and then fully charge the battery so that the electronics can calibrate to the actual battery capacity. Give it a try.

 

[casebomber]

how old is that batt? my blackberry tends to use a significant amount of juice to "boot" the rim os.

 

[Mr Happy]

Battery monitors don't directly use the battery voltage to indicate remaining capacity, they use a computer that integrates power usage over time. With older batteries the battery computer may be off a bit. Cycling the phone from full to empty a few times may help to recalibrate the computer, or maybe you just need a new battery.

 

[MarioJP]

I always have been charging my phone when battery percentage reaches 10%. Another thing i noticed is the charging current is being reduced. I know this because when it was new the phone would get kind of warm close to hot sometimes the phone would stop charging on its own if temps reaches 41C, and charges the battery pretty fast.

Now the phone seems cool and takes quite awhile during charging. In fact when the battery level reaches 80%, gets stuck there and then stays there for a good awhile and then jumps to 99%. During this time the phone is cold.

I am using a battery app that gives me this level of detail info about the battery. Phone is a blackberry bold 9700. Lithium ion batt 1500mAh. I had this phone for about a year. When battery hits 20%, voltage is already at 3.4v-3.2v and phone just dies without any warning.

 

[OverBoard]

I always have been charging my phone when battery percentage reaches 10%.

Always waiting until your battery level reached 10% before charging (over your 1 year ownership of the phone) stressed the battery during this time.

It is usually better to not let it run down in normal use so much before charging. To re-calibrate it as others have mentioned, it is OK to let it run down to 0% on occasion, but not everyday.

I try to recharge when it hits 30-60% and I am near a charger.

Try a new battery or borrow a friends battery and see if you are still getting strange behavior (which are sometimes symptoms of a battery going bad).

 

[Mr Happy]

Is this the same phone where you have been using a mobile battery boost charger?

Since it seems like you may have killed the phone battery in only a year of use, this might be a warning to others to use the manufacturer provided charger and to use "boost" chargers sparingly.

Lithium ion batteries are not supposed to get warm or hot during charging. If they do, this might be a sign they are being charged too rapidly. When I charge my iPhone from empty (the iPhone has a big lithium ion battery inside it) it gets a little warm, but only barely noticeably so.

 

[MarioJP]

Is this the same phone where you have been using a mobile battery boost charger?

Since it seems like you may have killed the phone battery in only a year of use, this might be a warning to others to use the manufacturer provided charger and to use "boost" chargers sparingly.

Lithium ion batteries are not supposed to get warm or hot during charging. If they do, this might be a sign they are being charged too rapidly. When I charge my iPhone from empty (the iPhone has a big lithium ion battery inside it) it gets a little warm, but only barely noticeably so.

The AC adapter that came with this phone would get almost hot during charging and its rated at 700mA. Mobile charger rated at 800mA. Now the ac adapter does not work properly anymore for some odd reason. So I am forced to use the PC or mobile charger for now. As for the mobile charger. The odd thing is I tested it on the iphone since my friend needed to charge his phone and we were away from any outlets that day. Both the iphone and mobile charger are cool to the touch. Even the AA cells are at cool temps from start to finish and didn't seem that demanding on the mobile booster as all the 3 led were constant on (very rare or at all would you see all 3 led lit up when my blackberry is plugged). But when i plug in my blackberry bold the mobile charger gets a bit warm close to hot. Something tells me this phone has a weird charging circuitry.

The mobile charger itself seems to regulate the power. In other words the phone will only draw what it needs as long as it does not exceed the max amp capacity for the mobile charger, and also when I was charging my phone on the PC when it jumped to 100% I immediately disconnected the phone and it was flickering from 100 to 83 back and fourth for a short period and jump back to 100 when i plugged the phone again. Weird???

 

[MarioJP]

I have determined that the phone battery has lost 30% of its original capacity. I used a usb AC adapter this time borrowed it from my friend. Nifty adapter as you can turn any AC outlet into a USB port. The results are the same if not much worst. Either the controller that monitors the battery is screwed up or the cell is starting to show its age. My phone died when the battery level hit at 30% of it's capacity. This time I was web surfing, instant im and many programs running in the background. And the network was on 3G. Furthermore I pull the battery out, put battery in, phone booted up with only 2% left in the battery. How the hell did it went from 30% to a big jump of 2%??

 

[__-_-_-__]

I use this great software on my nokia: http://store.ovi.com/content/61776
it shows current energy use etc etc very useful.