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Subject: Re: heating
From: Chris Holt (
Date: 2002-12-19

It sounds more like the batteries failed. Unless something shorted them,
they should have depleted slowly enough for the charge circutry to pick up
the large drop and charge them again.

I've never seen a batteries charged indication when I have USB connected on
my AJBR 20, it always indicates charging. Mine never seems to get
excessively hot either, even when I copy large numbers of files. Not sure
if I've ever matched a three hour session. I recently replaced the OEM
cells with a set of Eveready 1850s, and have only noticed increased run and
charging times, temperatures seem to be about the same.

You could try popping the battery covers before a long session, I guess.


----- Original Message -----
From: "Doug" <>
To: <>
Sent: Wednesday, December 18, 2002 10:38 PM
Subject: Re: heating

> I had deep discharge off. I don't think my batteries are bad or anything
> that (although I can't be certain). As for reproducing results, I don't
> on copying files for 3 hours straight again anytime soon, because this is
> produced the problem. What I was referring to originally was that in the
> charging algorithm doc, there was a reference to the shut off condition:
> -----------------
> Delta peak means to detect that the battery voltage goes down when the
> batteries are full.
> Two facts on batteries are the reason why this works:
> - If the batteries are full, the charging current cannot charge the
> anymore. So the energy is absorbed by heating up the battery.
> - Each battery has a negative temperature coefficient, that means the
> goes down when the temperature goes up.
> -----------------
> As you can imagine, I'm not much of an expert on the charging algorithm,
> however I have an aching suspicion that this--barring any defect in my
> unit--was cause for the shutdown.
> Tell me if you think the properties of the batteries or the algorithm
> could have caused the batteries to drain because of the heat.
> -Doug
> __________________________________________________
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Page was last modified "Jan 10 2012" The Rockbox Crew