Rockbox mail archive
Subject: Re: BATTERY-FAQ and the FM
From: Neon John (johngd_at_bellsouth.net)
On Tue, 3 Jun 2003 16:06:23 +0200 (CEST), Daniel Stenberg <daniel_at_haxx.se>
>On Tue, 3 Jun 2003, Mike Holden wrote:
>> I didn't think there was much to put!
>Perhaps it isn't that much, but when I scanned through it I could find
>several mentions about Recorder and Player but there's not even one single
>mention of 'FM' in there. ;-)
>> Hardware controls the charging. There are no user-replaceable batteries
>> available (you must return the unit to Archos as they will not ship
>> batteries). I think the charger is the same as for the recorder, but I can
>> verify the charger values later on.
>Yes, those are details I think could benefit users if present in there.
>> What else is needed? Typical runtime from a fully charged battery? TIme to
>> charge a battery from empty?
>If someone has the info then I think we could add it, yes.
18. "What is different about the FM recorder's battery"
The FM Recorder battery system is completely different from any previous
Archos product. The FM Recorder (FMR) uses a 2200 mah Lithium ion
rechargeable battery. In addition to its higher capacity, this battery is
thinner than the AA's the other Jukeboxes use and has no memory effect.
The charge management is controlled completely in hardware (an LTC1734
IC.) Rockbox has no control over charging. The charge process is fairly
fast. About 50% charge is applied in the first hour. The rest takes up to 3
more hours. A higher capacity power adapter such as the Radio Shack 273-1762
6 volt, 1 amp universal AC adapter with the "H" tip will somewhat speed the
charge over the factory supplied adapter.
There is no need for any special discharge or charge routine with the Li Ion
battery. The charge control chip completely manages the battery's charge and
the hardware turns itself off when the battery has been discharged as much as
19. "Can I get a replacement battery?"
Officially no. Archos, in their FAQ on their web site, describes the battery
as a "life of the unit" device. They further say that they will supply a
replacement battery if the supplied one goes bad.
Unofficially, this battery is a simple assembly that consists of two 1100 mah
cells in parallel, physically taped together. There are any number of
companies that make replacement battery assemblies. This author has not yet
tried to purchase a replacement for the FMR but he has for other applications.
It should not be much of a problem.
20. "What sort of battery life can I expect"
This is highly dependent on the use and encoding bitrate of the MP3. It can
range from as little as 4 hours while playing high bitrate (>300kbps) MP3s to
as long as 14 hours playing 32kbps audio books or similar talk-oriented
materials. The higher the bit rate the more often the hard drive has to spin
and thus the shorter the battery life.
21. "Does the FMR charge its batteries through the USB port?"
Yes, though slowly since USB is limited to 500 ma. Charging is reduced or
eliminated when the FMR is connected through a passive hub. If a PCMCIA USB
adapter is being used in a laptop or similar device, it is very important to
connect the external power supply if one is provided. The PCMCIA port cannot
supply sufficient power by itself. The Belkin USB 2.0 adapter, for example,
comes with a "wall wart" power supply that can be plugged into the PCMCIA
22. "Does the USB port supply enough power to run the FMR?"
During playback it is fairly close. While doing disc-intensive activities
such as copying files onto the FMR, defragmenting the FMR drive, etc, the USB
port does NOT supply sufficient power. The internal batteries are gradually
discharged. The use of the external power supply addresses this problem.
23. "Is the Rockbox state-of-charge indicator accurate"
Yes, at least in the author's unit. The battery capacity in the config menu
must be set to the Li Ion's capacity (2200 mah) instead of the default 1800
mah for this to be true.
24. "how to I access the battery?"
First off, I recommend not doing so unless there is a need. The battery
compartment hardware is fairly weak looking.
There appears to be two different battery compartment lids, one with screws
and one without. This is the lid at the TOP of the FMR above the display.
For the lid without the screws, simply insert a small flat screwdriver or
similar object in the slot and GENTLY pry toward the back of the unit. The
pried end will pop up. Pull the lid forward to disengage the metal fingers
from under the case. The battery is a tight fit so shaking the battery out is
the easiest method.
(SOMEONE WITH A SCREW-TYPE LID PLEASE CHECK THIS) For the screw-type lid,
remove the two screws and then follow the above directions.
When you re-insert the battery, MAKE SURE YOU OBSERVE THE PROPER ORIENTATION
AND POLARITY! The battery can be inserted backwards. The battery in this
author's unit (purchased approx 05/03) is marked with the capacity and
orientation. Others report different markings. The key is to pay careful
attention to how the battery comes out and to mark it if necessary.
25. "Is it normal for the unit to get warm during charging?"
Yes. It will get slightly warm, perhaps a 10-15 deg F rise, when charging.
It will get slightly warmer if hard drive activity is also taking place. If
continuous hard drive activity is underway, such as defragging, the unit will
get considerably warmer. It should NOT get uncomfortably warm.
Some users have reported that their units get quite hot during charging. The
cause is unknown, though at least one user reported that a hard reset (holding
down the "OFF" button for >5 seconds) seemed to solve the problem. Li Ion
batteries are not as sensitive to heat as NiMH cells so the normal slight
heating is of no concern. If your unit appears to be getting more than
slightly warm, disconnect the charger and execute a hard reset.
26. "I notice that the battery indicator sometimes goes up and down a few
counts. Is this normal?"
Yes, this is normal behavior. This is often seen right after hard drive
activity which presents a very large load to the battery.
John De Armond
Cleveland, Occupied TN
Page was last modified "Jan 10 2012" The Rockbox Crew