[Personal log] Battery contact-issue observations

asked 2014-09-30 15:21:49 +0200

kimmoli
7188 ●94 ●133 ●160

http://www.kimmoli.fi/

updated 2014-11-20 11:36:29 +0200

Finally. I have the sudden shutdown / reboot issue on my precious.

Just wanted to make this post to write my observations down somewhere publicly. There is absolutely no need to comment this question, no need to mark it as duplicate. I don't expect any answers to this.

But feel free to follow this.

I have no paper-below-battery-fix (i know it, and other tricks too). I have had no similar issues before, they started few days ago out of blue, and seems to escalate (as i expected).

I'll keep up taking notes of symptoms, before disconnecting my battery for further investigations.

I charge my battery every night. Typically 70% after days work, 40-30% when plugging into charger at around midnight. Maybe i could be considered as heavy user.

• 2014-09-24 - Phone has shutdown while in my pocket. (was driving around with ATV)
• 2014-09-27 - Sudden shutdown when using camera at low-mobile-network situation. Don't recall battery level.
• 2014-09-28 - Evening, battery down at ~35%. Then suddenly beeps for low battery at 9%, 7% and shutdown controlled.
• 2014-09-29 - Sudden shutdown when calendar reminder + OLED blinking Battery was again about ~35%. Booting up took few loops. Battery went from 35% to 19% really fast and continued to reduce - managed to get in charger.
• 2014-09-30 - Confirmed yestrerdays obsrevation that first few 100% --> 97% goes really fast after taking off from charger. Before it lasted for like 2-3 hours, now 30-60 mins.
• 2014-09-30 - 2 Reboots.
  • First: Battery 64%, just reconnected to mobile operator acc.to logs (entries on same sec).
  • Second: Battery 48%, Signal strength just dropped to 19. After waking up battery 34%
• 2014-10-01 - Reboot when starting camera, battery 74% (after reboot battery 66%)

• 2014-10-02 - Reboot when starting browser, battery 76% (after reboot battery 71%)

  • Multiple reboots, starting browser, starting camera, bright light to make display autobrightness adjust to max.
  • I'm patient person, but now i had enough of it. Time to take battery off and check the situation.
  • Battery level before taking it out is 58%
  • Some photos of contacts, see below. Added CG60 to contact areas
  • After restarting battery capacity 66%

• 2014-10-06 No reboots/Shutdowns since lubricating. Drained battery to ~10% and tried to cause reset; Full brightness, browsing, camera, poor mobile coverage, etc. but no. I'll keep following it for as long as it takes, month or two.

• 2014-10-08 shutdown in pocket, due low battery

Photos

Battery contacts right after taking it out from phone 2014-10-02 :

The whole area was covered with whiteish smudge. On one there is sharp "scratch" looking artifact, don't know what has caused it. I have not tampered with battery (but it looks like DMM meter lead-tip-mark)

On the phone side contact, there was small darker areas on the tip of contact. poor pic.

Grease'em up

I have Electrolube CG60 contact lubricant, and without making any further cleaning, i did apply small amount of it to the battery side contacts: (this 25g cyringe of this stuff is a lifetime supply :) )

The CG60 has UV traces, which nicely shows kinda even distribution (which actually doesn't make sense due the shape of phoneside contacts)

Before making conclusion, i need to follow the situation with contact lubricant, but first impression is good.

DC/DC converters has different current draw mechanism than linear regulators; (Just a comparison) but this might explain behaviour when battery voltage (l. capacity) goes down.

• DCDC = Pin ~= Pout --> Input voltage drop causes current to increase (add some series resistance which causes more voltage drop and current to increase even more - we are suddenly in a unstandable loop)
• LDO = Iin ~= Iout --> Input voltage drop causes input power to drop (input current stays ~same regardless of input voltage)

in /var/logs/systemboot.log suspicious events are two consegutive Startup: loggins.

20140923_224352 Shutdown: User Power Key
20140923_224420 Startup:  pwr_on_status=pwr_on_by_pwr_key
20140923_224420 Received: dsme internal state USER
20140924_163735 Startup:  pwr_on_status=pwr_on_by_pwr_key

.

20140926_175627 Startup:  pwr_on_status=pwr_on_by_pwr_key
20140926_175627 Received: dsme internal state USER
20140927_152410 Startup:  pwr_on_status=pwr_on_by_pwr_key
20140927_152411 Received: dsme internal state USER
x-no-time-stamp Startup:  preinit ignored pwr_on_by_RTC
20140927_164618 Startup:  pwr_on_status=pwr_on_by_RTC
20140927_164618 Received: dsme internal state USER

.

20140928_010650 Received: battery  empty
20140928_010659 Received: dsme internal state SHUTDOWN
20140928_010706 Shutdown: Battery empty
20140928_010729 Startup:  pwr_on_status=pwr_on_by_USB
20140928_010730 Received: dsme internal state ACTDEAD
20140928_010756 Received: dsme internal state REBOOT
20140928_010800 Shutdown: SW reboot request
20140928_010823 Startup:  pwr_on_status=pwr_on_by_SW_reboot

.

20140928_153647 Startup:  pwr_on_status=pwr_on_by_pwr_key
20140928_153648 Received: dsme internal state USER
20140929_232351 Startup:  pwr_on_status=pwr_on_by_pwr_key
x-no-time-stamp Startup:  preinit ignored pwr_on_by_RTC
20140929_232415 Startup:  pwr_on_status=pwr_on_by_RTC
x-no-time-stamp Startup:  preinit ignored pwr_on_by_RTC
20140929_232454 Startup:  pwr_on_status=pwr_on_by_RTC
x-no-time-stamp Startup:  preinit ignored pwr_on_by_RTC
20140929_232530 Startup:  pwr_on_status=pwr_on_by_RTC
20140929_232530 Received: dsme internal state USER

.

20140929_232530 Startup:  pwr_on_status=pwr_on_by_RTC
20140929_232530 Received: dsme internal state USER
x-no-time-stamp Startup:  preinit ignored pwr_on_by_RTC
20140930_171705 Startup:  pwr_on_status=pwr_on_by_RTC
20140930_171706 Received: dsme internal state USER
x-no-time-stamp Startup:  preinit ignored pwr_on_by_RTC
20140930_203814 Startup:  pwr_on_status=pwr_on_by_RTC
20140930_203814 Received: dsme internal state USER

.

20140930_203814 Startup:  pwr_on_status=pwr_on_by_RTC
20140930_203814 Received: dsme internal state USER
x-no-time-stamp Startup:  preinit ignored pwr_on_by_RTC
20141001_154245 Startup:  pwr_on_status=pwr_on_by_RTC
20141001_154246 Received: dsme internal state USER

.

20141002_085221 Shutdown: SW reboot request    ## my own reboot
20141002_085255 Startup:  pwr_on_status=pwr_on_by_SW_reboot
20141002_085256 Received: dsme internal state USER
x-no-time-stamp Startup:  preinit ignored pwr_on_by_RTC
20141002_125212 Startup:  pwr_on_status=pwr_on_by_RTC
20141002_125212 Received: dsme internal state USER

.

20141008_184908 Received: battery  empty
20141008_184916 Received: dsme internal state SHUTDOWN
20141008_184922 Shutdown: Battery empty
20141008_195239 Startup:  pwr_on_status=pwr_on_by_pwr_key

• 2014-11-20: Update
  • With lubricated contacts, i have had "reboot-free" time from 8th October until 12th November, but only as i had to take battery out for getting my phone so stuck that it was the only way to get it responding.