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1 Q1: Are my batteries charged all the time when connected to my Player/Recorder?
2 A1: Player: the charging is all done by hardware and the exact functionality
3 is hard to determine. It is however not recommended to keep the charger
4 connected for more than 10-15 hours if you're not using the unit.
6 Recorder: no. The charging algorithm is carefully crafted in to not wear
7 out the batteries any more than necessary. If you're using your unit
8 connected to the charger most of the time, use the 'deep discharge' option
9 to save your batteries somewhat.
11 Q2: Will keeping my charger connected a long time damage my batteries? Can I
12 leave it over night?
13 A2: There's a deep discharge mode and you can switch trickle charge on and
14 off. If you use your AJB connected to the power supply the whole time,
15 select "deep discharge on" and "trickle charge off". If you want to charge
16 your AJB over night and take it with you the next day, select "deep
17 discharge off" (that it starts charging immediately) and "trickle charge
18 on" (that the batteries remain full).
20 Trickle charge is needed to keep the batteries full. That's necessary
21 because the device will stay powered on and continue to consume some power
22 from the batteries (the hardware does not allow running from the charger
23 without charging batteries, or powering off with the charger connected).
24 The trickle charge time is 12 hours. It should be enough for you to
25 disconnect your AJB in this time and turn it off / use it. However, after
26 12 hours of trickle charge, it will turn it off, the batteries are
27 discharged and another charge cycle is started.
29 As the Battery FAQ at http://www.greenbatteries.com/ puts it:
31 "A NiMH battery can be charged and discharged hundreds of times, but
32 whether that means 200 times or 800 times has a lot to do with how (you
33 use it)".
35 Q3: Does Rockbox charge the batteries more/less/worse/better than the Archos
36 firmware?
37 A3: Player: Rockbox doesn't affect the charging on Players, it is all done
38 by hardware logic out of software control.
40 Recorder: The whole algorithm is made to carefully charge the batteries
41 full and keep them full after that with a trickle charge option. Many
42 documents about charge ICs were considered. If you want to know details,
43 then look into docs/CHARGING_ALGORITHM. If you have comments, write to
44 mail@uwe-freese.de or the Rockbox mailinglist.
46 Test results with trickle charge (battery capacities measured with an
47 external charger, Model "Conrad Electronic Charge Manager 2010", ~100
48 EUR):
50 - after normal charge and top off time: 1798, 1834, 1819, 1815 mAh
51 - after normal + top off + trickle charge (12h): 1784, 1748, 1738, 1752 mAh
52 - charged with external charger: 1786, 1819, 1802, 1802 mAh
54 You can see, whenever you take your AJB with you in the 12h trickle charge
55 period, the batteries are at least 97% full. :)
57 Q4: What kind of batteries are there in my factory default Player/Recorder?
58 A4: Both ship with 1500 mAh NiMH (Nickel Metal Hydride) batteries.
60 Q5: Is it hard to change the batteries? Does it void my warranty?
61 A5: It is not very hard - the Archos manual and the FAQ on their web site
62 describe how to do it. Their technical support confirmed that replacing
63 the batteries with NiMH cells (of different capacities) will not void the
64 warranty. Just don't remove the screws.
66 Some units have been shipped with two sets of batteries, my Recorder 20
67 only had one set. Someone actually had Archos send him new batteries free
68 of charge after they had weared out, under the warranty.
70 Q6: How much do replacement batteries cost? Where can I buy them?
71 A6: http://www.greenbatteries.com sells 1800 mAh NiMH cells at $3.25USD each,
72 and I bought 4 of the same GP batteries for 20 euros in an home
73 electronics & household appliance store in Finland. NiMH batteries are
74 sold in almost all shops that sell consumer electronics, and in many
75 online shops. Browse around. There's a pretty good comparison between
76 different battery makes and models at the digital imaging resource site:
77 http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM In Germany,
78 www.reichelt.de sells GP 2000 batteries for 2,75 EUR (12/2002).
80 Q7: What kind of run-time can I expect on a set of fully-charged batteries
81 when running Rockbox?
82 A7: For the stock 1500 mAh cells, from 6 hours to 8 hours, depending on which
83 charger was used (see Q3) and the bitrate you use (higher bitrate means
84 more harddisk runtime). It depends a lot on the condition of the
85 batteries. With 2000 mAh batteries, you should reach about 10 hours or
86 more. We are looking into implementing more battery-saving techniques in
87 rockbox to make it rock longer. If you have a modified AJB with 8 MB, you
88 can reach playing times of up to 16 hours with 2100 mAh batteries.
90 Q8: Can I use different batteries in my Archos? How much playtime would
91 I gain by using 1800 mAh batteries instead of the 1500 mAh ones?
92 A8: Only use NiMH-type rechargeable batteries. It is considered to be safe to
93 use NiMH batteries of different capacities though, a lot of people have
94 purchaced 1700 or 1800 mAh batteries to replace the stock 1500 mAh cells
95 and have the device run a bit longer. 2000 mAh batteries are just
96 appearing in shops are equally good to use.
98 In theory, running time = capacity of batteries / current drawn by device,
99 so running time should increase linearly by the capacity, and 2000 mAh
100 over 1500 mAh should give 33% longer running time. In practice, the mAh
101 ratings are more or less tuned up by the marketing department (think of
102 watts on the back of "hi-fi" speakers and amplifiers) and what you
103 actually get out of the cells is something else than what is printed on
104 them. Check the excellent imaging-resource link above for details!
106 Q9: Can I use non-chargeable batteries in my Archos?
107 A9: This is not recommended. The unit has been designed to operate with four
108 1.2V batteries producing about 4.8V at most, and using 1.5V alkaline/zinc
109 carbon batteries will produce around 6.0V, which will heat up the unit a
110 lot more and might even damage it. The Archos manual explicitly tells you
111 not to do so. Also, if you connect the charger, it may even destroy both
112 the batteries and the unit.
114 Q10: Can I use a different charger?
115 A10: The short answer is: Using a different charger will void your warranty
116 and can be dangerous to your unit, so we can not recommend it.
118 On the other hand, people have successfully used different chargers with
119 similar specifications as the stock charger. The charger must have the
120 same kind of connector with same polarity (center positive/+). The
121 charger should supply at least 7-8 volts, and if it provides more than
122 10V, it probably should be regulated to 10V (do not directly plug it in
123 your 12V car battery or it's charger!). The universal travel charger
124 sold by Archos is specified at 12V, 1.2A so that's probably the maximum
125 rating you should use. A good circuit for powering from a car battery or
126 other source with a higher voltage would be a 600 mA fuse and a 10V
127 regulator like a 7810 of your favourite manufacturer in series.
129 Inside the Jukebox there is a regulator which limits the charging current
130 applied to the batteries. The higher the input voltage, the hotter this
131 IC gets. Don't use an input voltage above 12V. Using lower charging
132 voltage < 10V will slow down the charging. But the rockbox charging
133 algorithm should work then, too.
135 These are the output voltages of an original archos power supply:
136 - connected to AJB Recorder, not charging: 13,7 Volt
137 - connected to AJB Recorder, charging: going down to 10,4 Volt
139 Here is how changing the input voltage changes the charging current:
141 voltage charging current (limited only by the AJB)
142 ------------------------------------------------------
143 7,0V 10 mA
144 7,5V 30 mA
145 8,0V 50 mA
146 8,5V 70 mA
147 9,0V 140 mA
148 9,5V 250 mA
149 10,0V 330 mA
150 10,5V 350 mA
151 11,0V 350 mA
152 11,5V 350 mA
153 12,0V 350 mA
155 To summarize:
157 - do not use an input voltage > 12V (it will only heat up the regulator)
158 - optimal input voltage is 10V (regulated)
159 - use a fuse of ~600mA
160 - using a different charger voids your warrenty
162 Many people are happy using an external quick charger which is specified
163 to work with NiMH batteries. This is completely safe and will not void
164 your warranty.
166 Q11: Can I buy a replacement charger exactly as the one Archos shipped?
167 A11: The FAQ on the Archos web site and the top of the charger both read:
169 Output: 9VDC 600mA
170 Center positive (+) polarity
172 The universal travel charger sold separately on the Archos web site is
173 specified for 12VDC, 1200mA output.
175 Chargers with similar (or user-adjustable) properties are available at
176 shops selling consumer electronics.
178 Q12: I often need to stop my player for about 15 minutes or so, and when I do
179 it runs off it's batteries. I was wondering, which is best: shutting the
180 player down completely and rebooting it when I want to listen again, or
181 leaving the unit on? Which way does it draw more power?
182 A12: In our testing we found the following results:
183 HDD off, backlight off, idle 94 mA
184 HDD off, backlight off, play 97 mA
185 HDD off, backlight on, idle 129 mA
186 HDD off, backlight on, play 131 mA
187 HDD on, backlight on, play 230 mA
188 HD on, reading, backlight off ~ 600 mA
189 HD spin up before read max 800 mA
191 Using the power draw measurements shown above, lets look at the numbers:
192 Power-down and restart vs. paused for 15 minutes.:
194 Pause for 15 minutes will draw: 94 mA / 60 minutes * 15 minutes =
195 23.5 mAh.
197 Power-down and restart will draw about (800mA / 3600 seconds * 3
198 seconds = 0.6666 mAh) + (600 mA / 3600 seconds * 6 seconds = 1.0 mAh) +
199 (230 mA / 3600 seconds * 8 seconds = 0.5111 mAh) = 2.18 mAh total used.
201 Thus, leaving it paused for 15 minutes draws more power (23.5 mAh) than
202 turning off and then on again (2.18 mAh).
204 So where is the break-even point?
206 Each second of pause will draw about 94 mAh / 3600 seconds = 26 µAh.
208 2.18 mAh / 26 µAh = 2180 µAh / 26 µAh = 83.5 seconds
210 Thus a shutdown and restart uses as much power as 83.5 seconds of pause.
212 Q13: When I plug in the charger when the Recorder is turned off, it turns
213 itself on and starts charging in the Archos software? What's up?
214 A13: There is a switch in the DC IN jack of the Jukebox - when a charger (or
215 whatever) is plugged in, the unit is powered on, even if the charger is
216 not plugged in a mains outlet.
218 If the charger is providing power at this point, the Archos firmware
219 located on the FLASH ROM does not load a new firmware version (like
220 Rockbox) from the disk, but goes into charging mode instead. You can use
221 this feature to get to the Archos charger if you want to.
223 However, if you put Rockbox in flash, it will always charge with the
224 Rockbox charging algorithm.
226 Q14: When I plug the charger in my Recorder, it doesn't immediately start
227 charging the batteries!
228 A14: When Rockbox is running on the Recorder (the device has been booted
229 without the charger) it's power management code runs once per minute
230 (thus the charge level and charging status is only updated every minute).
231 If the battery is not full, it will start charging. If the 'deep
232 discharge' mode is enabled in the settings menu, it will start charging
233 only when the battery is almost empty.
235 Q15: What about the memory effect? Should I be worried about it or not?
236 A15: That depends on who you ask. ;-) NiMH sellers say NiMHs are better and do
237 not have a memory effect, but the usual opinion seems to be that they do,
238 although it is very small.
240 However, if you use your AJB connected to the charger all the time,
241 we recommend you to use the deep discharge option.
243 Q16: When I start my Jukebox, (dis)connect the charger and browse through the
244 directories, the battery level changes a little bit. Sometimes it's even
245 going up without the charger is connected! What's wrong?
246 A16: Nothing's wrong. The battery level is calculated out of the voltage.
247 Because disk spinning, LED backlight, charger all influence the actual
248 battery voltage, it is usual that the battery level is going a little bit
249 up and down sometimes. This cannot be avoided although we tried to make
250 the battery level display as little confusing as we could.
252 Q17: My batteries are at 92%, the charger is connected to my recorder, deep
253 discharge is off. But charging doesn't start. What's wrong?
254 A17: Charging starts if the battery level is below 85%. This is because
255 charging batteries that *are* already more or less full is not good for
256 the batteries and the end of the charging cycle can't be detected safely.
257 So it's better to start at a level at least as low as 85%. If you want
258 to have full batteries in the morning, leave the charger connected over
259 night. Charging will then start some hours later. The second possibility:
260 Use the Archos charging algorithm. At least, your batteries will be full
261 one more time. ;-)
263 Q18: Why does rockbox show a question mark for the battery level?
264 A18: Rockbox waits for about a minute to show a battery reading, to increase
265 the reliability of the reading. In previous versions, the battery level
266 rockbox initially reported was always too low.