Battery life Qs; and "cell standby" on MID 7127
Greetings...brand new forum member here, with a 7127, received yesterday.
Three questions so far:
The manual refers to a "status indicator" that will turn blue when the battery is fully charged. I see no such light anywhere on the device. No blue light within the display screen either. I've charged the device for about 6 hours, with it turned off, and the battery info page shows 100% charge right after boot-up. I like an external battery charge indicator so perhaps I'm missing where it is...or is the manual incorrect?
Second, I saw no references in the ads for this device that it had some sort of cellular phone capability...something I didn't want anyway. But the battery consumption info shows a huge amount of power going toward "cell standby." Sitting here right now, in airplane mode, it shows 83% used by cell standby, and 18% used by the display. I can't see how to disable the cell phone features. Even thought I'm in airplane mode, with wifi off, lots of power appears to be wasted on this cellular feature.
Last...battery life in general. As a test, I'm running in airplane mode now, and after 1 hr 11 minutes, I'm down to 71% battery. No apps are running except "Spare Parts", status bar, and Email (which keeps starting up on its own), screen brightness at default of about 45%.
That extrapolates to only 4 hrs 4 minutes of run time WITHOUT even running wifi. The manual mentions 14 hrs of music and 6 hours of web browsing. I'm not doing anything, and wifi is off...but I'm looking at only 4 hours of runtime??? I specifically bought this version of the Coby because of its bigger battery, so this is very disappointing. Maybe battery life improves after a few charges/discharges?? I hope so!
Your replies most welcomed...
Last edited by RoyR; 01-01-2012 at 07:39 AM.
01-01-2012 07:08 AM
I am having the EXACT same problem. I have wifi on. My battery went from 100% to 80% within 2 minutes of unplugging it. I don't know what to do. It hardly runs an hour with wifi on.
Last night I went to bed and my 7127 has 46% battery left. When I woke up it was dead. I've been charging for over an hour now and am back up to 42%. Boy battery life is useless, even in standby. And I deleted the phone apps to avoid cellular standby time.
Now that I've had my device awhile, I'm actually seeing things are better than what I described in my post at the start of this thread.
Battery gauge--it is nonlinear. Upon first bootup after a charge, it shows a drop in percentage very quickly, which I have since learned is normal behavior for many battery gauges. If I extrapolate out from those first few minutes of runtime, the battery might last only a couple hours. But after running the battery all the way down until near 0% shows on the gauge, I wound up with 7 hours of runtime...wifi on the whole time, in airplane mode. That's slightly better than the 6.5 hours of web browsing the manual mentions. The battery gauge isn't faulty...it's just adjusting to the device's battery use, and that takes awhile. I also believe that the battery voltage drops at different rates as it discharges. The middle and lower voltages seem to drop more slowly over time than they do from peak voltage (4100mV) right after a full charge.
By the way...I didn't kill the battery. At 2% indicated on the gauge, the voltage read 3589mV. The recommended voltage cutoff for lithium polymer batteries is about 3200mV, so the battery was safely within its limits when the tablet shut off.
Cell Phone Standby--I have concluded that this is simply a misnamed item in the battery info section that is causing me and others needless consternation. I'm guessing--just guessing based on observation--that this term is a holdover from Android when it came out primarily as a cell phone operating system. What the label should say is System Standby. The 7127 of course has no cell phone capability, but it's electronics are always operating, ready for a task, and consuming more power than the display or the wifi. So trying to eliminate the battery drain from "cell phone standby" is impossible, since it's really the device's system that's always running.
I called Coby a couple days a go, and the guy I spoke with seemed befuddled at my question about cell standby, but he did confirm that the 7127 has no cell phone capability. Oddly he did not suggest the answer I postulated above. But with no cell-capability, I think the only reasonable explanation is that the System is standing by, and that's why the battery info says that's where 78+% of the power is going...and nothing we can do will reduce that.
Apps overriding settings-- I observed that the Aldiko book reader was running the display at 100% brightness, by default. There is an Aldiko setting for brightness that will reduce it, but you must set it inside Aldiko. Otherwise your book-reading will draw lots more power from the display than it does using other apps that use the Android settings. Perhaps other apps also override the tablet's settings so beware of that.
I guess I should admit I was premature in my earlier post criticizing the tablet. I can accept the 7127's battery life now that I have observed it's full runtime under normal operation.
Last edited by RoyR; 01-06-2012 at 07:46 AM.
Just a quick note to Brieezy and Skyhawk...
Charge your device with it OFF. I think charging with it on can affect how the charging system operates and may not give you a proper, full charge. I've read several cautions about this, particularly involving laptop computers. Battery life can be shortened while charging with some laptops on...at least on older devices without state-of-the-art charging circuitry. Apparently the battery can overheat, to its detriment.
Maybe the Coby charger does the opposite...it cuts off too early, as a protective measure, when it isn't sure of the proper charging rate with the device running. And with the tablet running, I'm certain the charging time is significantly increased anyway.