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Subject: RE: Irritating Sansa E200 Low Battery failure to boot

RE: Irritating Sansa E200 Low Battery failure to boot

From: Mark Ganson <mwganson_at_hotmail.com>
Date: Mon, 23 Feb 2009 20:39:29 +0000

> Date: Mon, 23 Feb 2009 12:50:51 -0500
> From: jacob.rau_at_gmail.com
> To: rockbox-dev_at_cool.haxx.se
> Subject: Irritating Sansa E200 Low Battery failure to boot
>
> Hello,
>
> When I run the battery near-flat on my Sansa E280, I get it to the point
> where I get a text message on the screen reading
> "Battery is too low
> System shutdown".
>
> I don't remember seeing this message before installing Rockbox, but I
> also can't find the offending lines in the RB source. I seem to recall
> the exact message being displayed on my brother's Rockboxed iPod nano,
> so I'm thinking it's a RB thing.
>
> I grep'd all over the RB source, and cannot find it. Is this message a
> part of the original firmware? Or am I missing something?
>
> If this is a RB thing, why? I mean, it's not like this player has a hard
> drive to wear out when the battery dies...I realize the quick fix is to
> keep my Sansa charged, but I don't see a reason for the current behavior.
>
> And if it's an OF thing, I will just have to bite it.
>
> Jacob

Based on what I've read about Lithium-Ion batteries, this is actually to protect the battery. If a Lithium-Ion battery, like the ones used in the Sansa e200, should ever become completely depleted it cannot ever be recharged again. This has something to do with the fact, as I understand it, that the charging circuitry requires a certain amount of feedback from the battery in order to prevent overcharging. In the case of Lithium-Ion batteries, overcharging results in overheating results in fire results in potential property loss and death, so it is a very serious safety issue.

The automatic shutdown when the battery gets to a low threshold point is there for that reason. While it's true the message and shutdown can be annoying, imagine how annoying it would be if you had to go out and buy a new battery every time you accidentally allowed it to go completely dead.

--Mark

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Received on 2009-02-23


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