Rockbox mail archive
Subject: Re: FM Recorder won't turn on / USB left connected overnight
From: Neon John (johngd_at_bellsouth.net)
On Tue, 21 Oct 2003 11:59:09 +0200, "Arturo Gonzalez" <agon_at_email.arizona.edu>
>Quite right, and thanks for preventing a potentially embarassing and
Not! The worst you can do to this type of LiIon battery is destroy it, swell
the case and/or make it melt enough to vent vapor. This type is NOT enclosed
in a hermetic pressure vessel and will NOT contain sufficient pressure for a
As long as you don't try to top off the battery, the procedure is completely
safe. In fact, during my testing at about 1 amp charge rate I observed less
than 0.1 deg F temperature rise in the battery. That is one reason the LiIons
are so efficient, they don't waste energy on heat.
I have spent a bunch of time trying to figure out how to bootstrap a
completely dead FMR. Since the unit tries to boot when power is applied and
since the hard drive needs the battery to spin up, booting becomes impossible,
resulting in a loop of boot-and-shut-down. I have not succeeded in getting a
nearly dead unit to boot enough to charge using only external power.
The other way to boot the unit is to hook external power through the internal
battery contacts using long shank minihooks or similar connection method. I
used a power supply but a general purpose Li battery can be used. Once the
unit is booted and the hard drive is stopped, the wall wart can be plugged in
and the bootstrap power removed. Insert the battery with the unit on and
booted and it should start charging.
It is much more straightforward and poses less risk to the unit to simply
remove the battery and charge it a bit as described in my previous post.
>Which brings me to my intial question--What type of charger should I get
>to recharge the unit since my US charger doesn't work in Europe.
6 volt DC, 1 amp. Do not try to use the 9 volt charger that the Studio and
Recorder use. Can damage the charging circuit in the unit. Voice of
John De Armond
Cleveland, Occupied TN
Page was last modified "Jan 10 2012" The Rockbox Crew