Where you bought it ? and how long the 20 % power lasts ?
It may be a wrong power indicator, which can be fixed via software update.

Добрый день! Та же проблема. Батарея емкостью все 1000 mah. Были проведены проверки разными программами. Емкость 1000 mah. Телефон куплен на aliexpress. Мне продали подделку?

Good afternoon! Same problem. The battery capacity of all 1000 mah. different programs were audited. Capacity 1000 mah. Phone bought on aliexpress. I sold a fake?

Just got my phone, it arrived finally from China to Australia. . My second blackviiew phone. First being bv6000 and the same problem with battery. The bv6000 battery is far superior. So much for being the same battery and also the keyboard is screwed, way too sensitive, downloaded Google keyboard and same s@#t. Checked glove mode and still the same. It keeps adding double letters or even triple. Omg do you know how long it took to write this. I mean really it's one day old

Yeah I noticed the super sensitive display and haven't found a fix for that but flashing the latest update will definitely fix the battery issue I was ready to turf it at the next bloke who complained about their iphone

mike_kostop wrote:

Hello I just bought the phone and something is not right with the battery!!It is supposed to be around 4000mah capacity right?But the battery lasts hardly one day and I barely use the phone!!! after a full nights charge the next day with no data and no wifi used and the phones battery goes to 20% this is unacceptable....I used an app to measure the battery and it said that its 1000mah not 4000mah....what is wrong???can anyone help me??

Same problem here. 100% to 15% in 6-7 hours. After this, almost 15 hours with 1%. After charging the battery, to 100%, the voltage was only 3.8V and again 5-7 hours until 15% but after hitting the 1% mark the phone shut down.
Additional, the proximity sensor is horrible and the calibration doesn't do anything.

I managed to upgrade the firmware to the latest, but it took me half a day and I am not sure that the battery problem is solved just with this upgrade because I used some battery apps also. The proximity sensor problem still not solved.
You should provide a user friendly solution. This is not normal guys.

Same problem here.
First time use 100% to 15% in 6 hours. An hour later 4% and then 15 hours with 1%. After recharge I checked the battery with some app and guess what: the battery is 1000mAh and at 100% it only have 3.8V.
After half day I managed to upgrade the firmware but again the battery showed 1000mAh. So I tried with some battery calibrating app and some other tweaks and I finally have 4180mAh battery. Even so, the battery life it's not so great. Maybe 20 to 30 hours with blu and wifi on and moderate use, but i can live with this.
The other problem is the crappy proximity sensor. I tried to re-calibrate it, but without any effect. Simply the sensor is a dud.
Really guys, you must do something and you should find a user friendly way to upgrade the firmware, not installing drivers and hackers software on Win 10 machine exclusively.