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2015-09-18
, 14:22
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Posts: 4,118 |
Thanked: 8,901 times |
Joined on Aug 2010
@ Ruhrgebiet, Germany
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#2
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2015-09-18
, 14:55
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Posts: 52 |
Thanked: 63 times |
Joined on Sep 2014
@ Germany
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#3
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The Following 2 Users Say Thank You to NobodyInPerson For This Useful Post: | ||
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2015-09-19
, 11:39
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Posts: 52 |
Thanked: 63 times |
Joined on Sep 2014
@ Germany
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#4
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2015-09-19
, 15:59
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Posts: 52 |
Thanked: 63 times |
Joined on Sep 2014
@ Germany
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#5
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R> source('NokiaN9-battery-period.R') Period: 24.02245 hours
# How long is battery life on the Nokia N9? # Find the period of charge of battery # Read CSV file BAT <- read.csv("NokiaN9-batterydata-5months.csv", sep = "\t") # Interpolate on regular grid APPROX <- approx(BAT$TIME, BAT$BATTERY,xout = seq(f = min(BAT$TIME), t = max(BAT$TIME), len = length(BAT$TIME))) # Get spectrum SPECTRUM <- spectrum(APPROX$y,plot=F) # Find maximum period # First find frequency of greatest amplitude # Invert this frequency to get the period # Multiply this period that is in units of timesteps with the timestep to get the period in seconds PERIOD <- 1/SPECTRUM$freq[which.max(SPECTRUM$spec)] * unique(zapsmall(diff(APPROX$x))) # Output period in hours cat("Period:", PERIOD / 60 / 60,"hours")
The Following 4 Users Say Thank You to NobodyInPerson For This Useful Post: | ||
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2015-09-19
, 17:22
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Posts: 578 |
Thanked: 994 times |
Joined on Dec 2012
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#6
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Interesting part: Curiously, these drops in charge of battery don't come together with voltage drops, as you can see in the image. So, either the voltage sensor inside the N9 is not very precise or (most likely) the voltage is not the only indicator for the charge of battery...
The key to the bq27520-G2 ’ s high-accuracy gas gauging prediction is Texas Instrument ’ s proprietary Impedance Track ™ algorithm.This algorithm uses cell measurements, characteristics, and properties to create state-of-charge predictions that can achieve less than 1% error across a wide variety of operating conditions and over the lifetime of the battery.
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2015-09-19
, 18:16
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Posts: 52 |
Thanked: 63 times |
Joined on Sep 2014
@ Germany
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#7
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2015-09-19
, 19:09
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Posts: 578 |
Thanked: 994 times |
Joined on Dec 2012
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#8
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The Following 2 Users Say Thank You to elros34 For This Useful Post: | ||
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2015-09-19
, 21:20
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Posts: 52 |
Thanked: 63 times |
Joined on Sep 2014
@ Germany
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#9
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2015-09-22
, 16:15
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Posts: 146 |
Thanked: 99 times |
Joined on Jan 2012
@ Lisbon, Portugal
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#10
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I wrote myself a script in R that saves several battery parameters of my N9 every couple of minutes, then puts this into a .csv file and creates a neat little .png graph that Billboard displays on the standbyscreen.
The change of the battery charge over time interested me because I wanted to understand these stupid 4%-drops that happen to occur everytime the N9 gets stressed with a not fully charged battery.
Things evolved and I started to log battery temperature, voltage and charging state as well to find a correlation or explanation for these drops. I didn't log the current, because I think this is highly variable and with a temporal resolution of around 5 minutes, it doesn't bring me much...
What I found out so far, is that the 4%-drops are not caused by a sudden voltage drop which I thought it was... At the moment, I don't have the time to dig further into this topic.
Anyway: I decided to share five months of logged battery data with you. Those of you who are familiar with some statistics can surely make use of it. Maybe you'll find something interesting!
See the attached .tar.bz2-file. It contains a TAB-separated-.csv-file with header which contains the following data:
The timestep is around 5 minutes, varies and is definitely not equidistant.
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Here are the sources:
Billboard-battery.R - the script that reads the data, saves it and produces the .png image to be displayed via Billboard on the standbyscreen.
Requirements:
batteryloop.sh - the stupid little endless-loop-script that calls Billboard-battery.R every 5 minutes.
Requirements:
So, get your hands going!
Greetings,
NobodyInPerson
Last edited by NobodyInPerson; 2015-09-19 at 08:34. Reason: datafile was faulty