Rockbox Technical Forums
Support and General Use => Hardware => Topic started by: EdisLeado on June 24, 2007, 01:40:05 AM
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sorry for another thread, but...
well, i dunno what's going on with the mp3 player -- but i've recently charged the battery and after using it for a little bit the numerical battery display went down to about 84 -- and with the theme i'm using, it says that it only has like 4 hours left on the battery if it's at 84. what the? isn't the e200 series advertised with 20 hours of battery life?
i even charged it to 100% one time and after using the thing for like an hour or two, a window popped up in rockbox saying that the battery was low and then it just shut off?
what is going on?
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The battery level display and estimated running time are awfully inaccurate on Rockbox. Actually the running time estimate is not even inaccurate but plainly wrong.
However, since this is not a serious issue it might not get fixed soon.
isn't the e200 series advertised with 20 hours of battery life?
Yes, but using Rockbox currently shortens your battery life a little. I got about 16 hours of continuous playback on my Sansa (without turning the backlight on).
i even charged it to 100% one time and after using the thing for like an hour or two, a window popped up in rockbox saying that the battery was low and then it just shut off?
I never had that happen on my Sansa yet. Even when the battery was low, it just shut off without saying anything. That's (as far as I know) because the shutdown is not triggered by Rockbox but by the hardware/bootloader.
If your battery had really run dry after just an hour or two I guess you might have to replace it.
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well, so far the "battery is low RECHARGE" message only came up once in rockbox for like a split second before shutting down. i forgot to mention i only bought this mp3 player like 2 days ago.
the rockbox manual says that i can change the battery capacity in the settings, but when i get there, it wont even let me -- no matter what button i click, it just takes me back to the previous menu.
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Changing the battery capacity setting does not affect the actual running time in any way. It's only used for calculating the battery level and estimated running time left.
Like I said, Rockbox does not power your player down when it thinks the battery is low, so it doesn't really matter what battery level it displays.
If your battery really died after just 2 hours it might be defective. You should check that by using the Original Firmware for a while.
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Changing the battery capacity setting does not affect the actual running time in any way. It's only used for calculating the battery level and estimated running time left.
Like I said, Rockbox does not power your player down when it thinks the battery is low, so it doesn't really matter what battery level it displays.
If your battery really died after just 2 hours it might be defective. You should check that by using the Original Firmware for a while.
Considering my system clock doesn't work either, it might actually be the battery. Otherwise, the MP3 player seems fine. Is it maybe because I'm keeping the MP3 player plugged in alot of the time and it's deteriorating the battery?
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Well, are you using an official build? I know this is the exact problem i am having with my build because of a patch but i havent had any problems using a daily build.
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It's about the same with every build I've tried (the official one and yours).
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The problem is about the same or the estimated time? As stated before the battery estimation on rockbox is not much short of dreadful, but the problem may be unique to a certain build.
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well, so far the mp3 player seems fine -- as far as the battery goes :/ (that broken system clock is still bothering me though) -- so i guess the estimation just really sucks.
oh yeah, estimation is the same no matter what build i use.
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Estimation has not been calibrated on newer targets, on my H160 it is very good. For some odd reason, the devs seem to focus on making the hardware work and removing bugs than on the runtime estimation. % battery left is correct, use that instead.
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The battery level display and estimated running time are awfully inaccurate on Rockbox. Actually the running time estimate is not even inaccurate but plainly wrong.
Well, to be exact, this is only an issue for the players using a PortalPlayer chip. Battery display and estimated running time are working great on all other devices (Iriver h100 and h300 series, Iaudio, etc.)
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Even the Gigabeat? I thought that was still in the throes of being calibrated ?
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And the runtime estimation is not calibrated on the Iaudios either - only the battery level percentage is...
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% battery left is correct, use that instead.
Except that it stays at 20% forever on my Sansa, then suddenly drops really low. But that's just before the player actually shuts off. :)
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Even the Gigabeat? I thought that was still in the throes of being calibrated ?
D'oh! Forgot about those ...
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Sorry for thread digging but the OP had the same problem as me.
When plugged into the wall, the battery % reads 100%. After being plugged in for around 10 hours, i unplugged it and it read 84% and about 4 hours of runtime left. People here have said how inaccurate the read out is, but its funny because thats about how long it lasted. Without doing a battery bench, and just from timing it myself at school, the player lasted from about 9am to 11:30am, which is far from the 12 hours other people are getting. I also charged it using the OF to the same effect.
It can't be the battery because I only changed the firmware a few days ago after having this player since July 2006 and consistanly getting 17 hours of playback after charging for about 2 hours every morning.
I read somewhere about changing a text file to fix the meter but i know nothing about programming and am somewhat overwhelmed by massive notepad filesÂ
I really hope I don't get another "Read the manual" response, or some sarcastic comment because i feel i have done my best to figure out the problem to no avail, and would really like to continue using RB.
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It's nearly physically impossible that you've had the same battery life since July 2006, because lithium based batteries decay over time. Please, do a proper test both in the original firmware on a full charge, and in Rockbox on a full charge, with equivalent settings (volume at the same loudness, equalizer, bass, treble, replaygain, crossfeed, etc all turned off).
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When plugged into the wall, the battery % reads 100%. After being plugged in for around 10 hours, i unplugged it and it read 84% and about 4 hours of runtime left. People here have said how inaccurate the read out is, but its funny because thats about how long it lasted. Without doing a battery bench, and just from timing it myself at school, the player lasted from about 9am to 11:30am,
I fixed runtime estimation the day before yesterday. Upgrade your build and it'll give you a more realistic run time.
Did you charge it in the OF? I think rockbox doesn't actually charge the battery. At least it sounds like your battery didn't actually recharge if its only reading 84% fresh off the charger. That or its amazingly dead.
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If you read some of the forums regarding Rockbox and Battery issues on the Sansa, then you would notice two things.
1. Rockbox is not optimized for PortaPlayer based players. Â This is due to the Rockbox team not having all the information regarding the chipset. Â As a result, they are unable to know what optimiztions can be made (i.e. what can be turned on and off) to help optimize battery life.
2. Rockbox and battery charging does not work will well. Â It has been documented somewhere that while running Dropbox, the USB cable only draws 100mA vs, 500mA in original Firmware.
This means that battery charging time under rockbox is 5 times longer and if you are actually running Rockbox during the charge, you might be barely breaking even if not actually trickle discharging.
So as it stands, the suggestions from the Rockbox team is to use Original Firmware for not only USB transfer, but also for battery charging.
There may be some future build which modifies the Rockbox USB charging routine, at which point we'll be able to use Rockbox while charging and actually be charging the battery.
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Yes I read all that before. The thing is, even though they are not getting an accurate estimate people are still getting around 12 hours from a full charge, which i know is down from the 17-20 in the OF. I went from getting about 16 hours to 3 hours, so I just want to know how to get close to the 12 hours others are getting.
I have been charging under OF, overnight sometimes, so its not because of trickle charging.
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I went from getting about 16 hours to 3 hours, so I just want to know how to get close to the 12 hours others are getting.
http://www.rockbox.org/twiki/bin/view/Main/SandiskE200BatteryMeasurements
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Maybe the problem is that it shuts off at 40% charge. My friend recently bougth an e280 and is getting the exact same 3-4 hours i am getting. Is there any way to chane the % at which it shuts down or is that a dev thing?
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See battery_level_shutoff in \firmware\target\arm\sandisk\sansa-e200\powermgmt-e200.c.
However, unless your battery is significantly different then the standard one, I doubt that is going to help you.
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so I just want to know how to get close to the 12 hours others are getting.
I have been charging under OF, overnight sometimes, so its not because of trickle charging.
And what are you doing in Rockbox. With OF, I simply played my music, pretty straight forward. However, with Rockbox, I play solitaire, Bubbles, Doom, etc. All this stuff takes more processing power and hence more power than simply playing music. Also realize that playing games, the backlight stays on constantly, where as in OF it rarely is on unless you are choosing an album, or otherwise navigating.
While there is no doubt that Rockbox in simple playback mode has approx 30 to 40 percent lower battery life in strict playback. Rockbox does indeed change the way you use your player, so you must keep that in mind.
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Ya i know that. The 3-4 hours was strictly music, and most of the time it was just playing, no nav. Iccaisionally i had tostart the song again cuzit would stop for no reason, buti assume thats a bug.
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Are you using an official Sansa cable? I'm not, and I'm having the same damn problem.
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I'm using the one that came with the player.
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I wasn't getting only 3-4 hours, but I was getting less than 12 (maybe 6).
Then again, I bought a reconditioned player, which might have come with a used battery!
Could try a new battery from an official sansa source.
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It can't be the battery because I only changed the firmware a few days ago after having this player since July 2006 and consistanly getting 17 hours of playback after charging for about 2 hours every morning.
Batteries are finicky- they do deteriorate over time and especially if you went from a low-drain situation to a higher-drain it could affect battery life.
Try fully discharging/charging a couple times?
The battery kit from Sandisk is only $20.
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Try fully discharging/charging a couple times?
That shouldn't affect anything. Li+ batteries don't suffer from memory effects like NiMH batteries do. I would lean more toward deterioration, as you suggested in the first sentence. Wikipedia estimates a 20% drop in capacity per year for Li+ batteries (http://en.wikipedia.org/wiki/Lithium_ion_battery#Disadvantages).
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good
info
Sorry, got mesmerized by your avatar pic. ;D
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Just after reading this thread. I was alarmed to notice that when in rockbox, once the battery meter says abotu 40% it just ticks down in about 20 mins rather than the 5 hours it says i have left.
I shouldnt be too alarmed it seems. I havn't done a full battery bench yet but the fact it drained VERY fast once it hit ~40% worried me.
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I have the same problem.
I only have the % listed on my WPS, since I the runtime estimate too unwieldy.
My Sansa goes to about 40% or so and I know it will shut off soon there after. I still get about 10 or so hours out of my player before hand...
I'm guessing that the threshold voltage for the low battery has been set too high somewhere in the source. Either that or my battery is knackered. Although I have only had my Sansa for about 9 months, and always fully charge and discharge it.
Anything I could do to help find out what's wrong..? Battery bench? Play around with the voltage setting somewhere?
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Just after reading this thread. I was alarmed to notice that when in rockbox, once the battery meter says abotu 40% it just ticks down in about 20 mins rather than the 5 hours it says i have left.
I shouldnt be too alarmed it seems. I havn't done a full battery bench yet but the fact it drained VERY fast once it hit ~40% worried me.
I can confirm this; it just happened to me. I'm going to update my Rockbox tonight after I've charged up my Sansa and let you know how I get on*
(* - I'm away from Christmas, so it'll be a while before I comment again...)
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Quote from: Rockmenot on December 18, 2007, 09:23:14 AM
Just after reading this thread. I was alarmed to notice that when in rockbox, once the battery meter says abotu 40% it just ticks down in about 20 mins rather than the 5 hours it says i have left.
I shouldnt be too alarmed it seems. I havn't done a full battery bench yet but the fact it drained VERY fast once it hit ~40% worried me.
I can confirm this; it just happened to me. I'm going to update my Rockbox tonight after I've charged up my Sansa and let you know how I get on*
All, This is "normal". If you look at the Wiki regarding the Sansa battery benchmarks, you will see that the battery discharge rate for the Sansa is fairly flat with two exceptions.
Battery discharge rate from a full charge is fairly rapid, and then flattens out quite a bit, until about 40%, at which point the discharge of the battery is accelerated.
Since any "percentage" or "time remaining" charge is simply based on the voltage readings at the given time, this "%" and "Time Remaining" reading is highly inaccurate due to the sharp discharge curve at the beginning and end of the discharge cycle.
Even the original firmware does not attempt to give a time remaining function as there is no real "mathematical" way to figure it out, and simply basing it on output voltage would not yield accurate results.
On my discharge tests, I've had the battery take almost two hours to go from 50% to 40%. Yet 40% to shutdown is less than an hour.
Plan on approx. 10 to 12 hours per charge (charge only using original firmware), and once you get down to about 42% you know you are going to have to plug in soon.
If you are looking for more battery time, run the device in original firmware, as that firmware is optimized for power, where as Rockbox is not.
Rockbox is better than it was, but 10 to 12 hours of "normal" use (use of backlight, volume level) is about what you are going to get. If you turn off all the EQ settings and simply run it continuous with no use of the backlight, you may be able to coax an hour or two more out of it, but the battery remaining level will always be inaccurate.
What would be nice is if we could change the range of the battery remaining feature so that we can only include the flat portions of the discharge curves. This would compensate for the sharp discharge curve at the end of the cycle. I'd set the "empty" percentage to be at approx 3.4 volts., as this is very close to the low power shutdown for the device.