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Sansa Clip ZIP:The care and feeding of a LiPO cell - I only want the best for it

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mcc01:
Hi,

Especially cause it seems to be hard to get a replacement battery for a
Sansa Clip ZIP I really dont want to shorten its life due to the lack of
knowledge about this topic...

Here:
http://batteryuniversity.com/learn/article/how_to_charge_when_to_charge_table
I read about the best way to charge a LiPO cell.
It seems to be better to neither empty the cell completly nor to charge to 100%
every time.

But:
The cell of the Clip ZIP has a PCB attached, which stops the current to prevent
too deep discharge and overcharge.
Furthermore I dont know wether 0% and 100% of Rockbox battery already take
a security margin into account, not to load up to the 100% of what the article is
talking about -- same for the other end.

So...what is 100% and 0% of the battery meter of rockbocks in the context of prolong
the life of the cell as much as possible?

Thank you very much for any clarification of this topic!
Best regards,
mcc

saratoga:
http://git.rockbox.org/?p=rockbox.git;a=blob;f=firmware/target/arm/as3525/sansa-clipzip/powermgmt-clipzip.c;h=5006c5834745799a64dcff2507464eaad36409ef;hb=HEAD

mcc01:
Hi,

I always like these kinds of RTFM one-liners of an answer without any additional human
word to avoid any chance to render the answer helpful. :(

So,  the source code says:
 /* The battery manufacturer's website shows discharge curves down to 3.0V,
   so 'dangerous' and 'shutoff' levels of 3.4V and 3.3V should be safe.

These are voltages only...and it is still not clear, whether these are the voltages,
below or above the cell will be killed or will explode (german "Entladeendspannung"
und "obere Kniespannung" (speaking in the sense of Delta-U...if this could
be applied to LiPOs also...dont know)) or whether these voltage will garantee,
that the cell will live long enough to skip the warranty time just enough or...
whether it ensures best lifetime...that in what I am interested in.

Again: In what relationship are 100% and 0% of rockbox battery meter to
those margins mentioned in the article which I linked in my initial posting?

And: Who is the manufacturer...?

Best regards,
mcc

saratoga:

--- Quote from: mcc01 on April 30, 2014, 02:44:48 PM ---I always like these kinds of RTFM one-liners of an answer without any additional human
word to avoid any chance to render the answer helpful. :(

So,  the source code says:
 /* The battery manufacturer's website shows discharge curves down to 3.0V,
   so 'dangerous' and 'shutoff' levels of 3.4V and 3.3V should be safe.

--- End quote ---

FWIW, those comments are probably referring to a different battery, since I bet that code has been copy/pasted a bunch.  I would only trust the battery voltages because they are (probably) measured.


--- Quote from: mcc01 on April 30, 2014, 02:44:48 PM ---Again: In what relationship are 100% and 0% of rockbox battery meter to
those margins mentioned in the article which I linked in my initial posting?

--- End quote ---

I think the only way you'd be able to determine this would be to get a couple dozen batteries, wear them down, and characterize their life cycle.   

[Saint]:
Battery technology is at a point (and has been for quite a while) where a consumer doesn't need to care about this at all.

It seems odd to me to be so concerned about this when the device in question is low cost and essentially disposable.


[Saint]

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