11-02-2017 12:12 PM
Both were charging with over 1A when I plugged the tablet to charger at about 80%. The charging current drops when the battery is closer to full. And the charging voltage was ~12V the whole time.
What I'm saying is that looking at the battery test there doesn't seem to be anything odd about the behavior.
After I unplugged the charger the batteries were discharging at about total of 1A (~400mA + ~600mA) which is in my opinion quite high when the tablet wasn't doing anything special. This discharge rate would yield about 10 hours of usage.
I think it's more about some Android bugs or preinstalled apps that are consuming too much in the background.
11-02-2017 12:17 PM
I believe the battery apps see only the mA related to the 4300mAh battery - when charging or discharging. So, when Accubattery reports 400mAh usage the actual usage is about 1000mA.
Does anyone have some other tablet with a big screen so we could compare whether 400mA is plausible discharge rate given the screen size?
11-02-2017 12:20 PM - edited 11-02-2017 12:23 PM
This is pretty insightful, eldis.
1A is a pretty high discharge current. If the battery test that you did in Engineering Mode is right, then this is a criticially important matter which should be resolved.
Lenovo's claim of 18 Hours of battery life with mixed use makes sense only when the power being used on average is 10200/18=566.67 mA. The battery consumption that Engineering Mode reports (1A) vs what the battery apps report (450mA) points to the fact that there is at least a software issue, if not hardware.
Android System is the culprit as many posts have pointed out. But so many processes are bunched under it that nobody has been able to figure out how to solve this even after rooting the device.
In any case, issues like these should be fixed as all our tablets must be under warranty. I'll ask the question again to the experienced folks here - "How to get Lenovo to respond and act on this critical matter?"
We need our battery life back, please!
11-02-2017 12:46 PM
The mixed use has 2 hours of music playback with screen off and 12 hours of reading (probably in the reading mode which reduces screen power consumption). I would compare to web browsing (~12hrs) or video playback (~14hrs). And I can't get anywhere near that with web browsing.
11-02-2017 12:53 PM
Yup, getting nowhere close to 14 hours too. I use it for reading books with AnyPen enabled. It lasts only for 8 hours maximum. Before updating, I remember that I used it for 2 days after unboxing at 50% battery. So, of course, it was the update that screwed things up. This was also confirmed by the people here, and xda-developers.
How to make Lenovo listen and act?
11-05-2017 10:16 AM
A Couple of page up, I posted regarded external tests using an ammeter, not potentially fooled apps. You can't really fool something measuring using Ohms Law from the wall...
Multiple charges, I rarely got anywhere over 4000maH into the battery. Obviously a 4300maH will have a cuttoff to prevent undervoltage and destruction of cells. Sure seems like something is cutting off early on the charge. I'm going to see about this engineering mode and what mine is doing.
11-05-2017 11:29 AM
Aeklund1, it was actually the photo that you had out that got me to explore what's going on because of the Watt-hours shown in it. It's not enough to measure amps if you don't know the voltage.
Your measurement says the voltage is 11.6V and total power about 46Wh. The power in full batteries is only about 4.2V * 10.2Ah ~= 43Wh. That 3Wh might be thermal and other losses. That actually sounds like you are able to charge both batteries very well.
Still, there's something wrong in the power consumption. Currently, I'm losing about 1.4% per hour with the screen off and 11% per hour with light usage.
11-09-2017 11:48 AM
11-09-2017 12:00 PM - edited 11-09-2017 01:00 PM
Thanks for the reply.. i was thinking of recommending it to my parents in law (they loved the projector idea since they spend the summer in a holiday caravan / trailer and find it hard to share videos / pics with visitors. Not sure i want to recommend it due to the battery and no exFAT support. (they had a samsung tab pro 12.1 that just broke and he never stopped complaining about the battery for 4 years)..
Is exFAT still an issue?