| Q1: Are my batteries charged all the time when connected to my Player/Recorder? |
| A1: Player: the charging is all done by hardware and the exact functionality |
| is hard to determine. It is however not recommended to keep the charger |
| connected for more than 10-15 hours if you're not using the unit. |
| |
| Recorder: no. The charging algorithm is carefully crafted in to not wear |
| out the batteries any more than necessary. If you're using your unit |
| connected to the charger most of the time, use the 'deep discharge' option |
| to save your batteries somewhat. |
| |
| Q2: Will keeping my charger connected a long time damage my batteries? Can I |
| leave it over night? |
| A2: There's a deep discharge mode and you can switch trickle charge on and |
| off. If you use your AJB connected to the power supply the whole time, |
| select "deep discharge on" and "trickle charge off". If you want to charge |
| your AJB over night and take it with you the next day, select "deep |
| discharge off" (that it starts charging immediately) and "trickle charge |
| on" (that the batteries remain full). |
| |
| Trickle charge is needed to keep the batteries full. That's necessary |
| because the device will stay powered on and continue to consume some power |
| from the batteries (the hardware does not allow running from the charger |
| without charging batteries, or powering off with the charger connected). |
| The trickle charge time is 12 hours. It should be enough for you to |
| disconnect your AJB in this time and turn it off / use it. However, after |
| 12 hours of trickle charge, it will turn it off, the batteries are |
| discharged and another charge cycle is started. |
| |
| As the Battery FAQ at http://www.greenbatteries.com/ puts it: |
| |
| "A NiMH battery can be charged and discharged hundreds of times, but |
| whether that means 200 times or 800 times has a lot to do with how (you |
| use it)". |
| |
| Q3: Does Rockbox charge the batteries more/less/worse/better than the Archos |
| firmware? |
| A3: Player: Rockbox doesn't affect the charging on Players, it is all done |
| by hardware logic out of software control. |
| |
| Recorder: The whole algorithm is made to carefully charge the batteries |
| full and keep them full after that with a trickle charge option. Many |
| documents about charge ICs were considered. If you want to know details, |
| then look into docs/CHARGING_ALGORITHM. If you have comments, write to |
| mail@uwe-freese.de or the Rockbox mailinglist. |
| |
| Test results with trickle charge (battery capacities measured with an |
| external charger, Model "Conrad Electronic Charge Manager 2010", ~100 |
| EUR): |
| |
| - after normal charge and top off time: 1798, 1834, 1819, 1815 mAh |
| - after normal + top off + trickle charge (12h): 1784, 1748, 1738, 1752 mAh |
| - charged with external charger: 1786, 1819, 1802, 1802 mAh |
| |
| You can see, whenever you take your AJB with you in the 12h trickle charge |
| period, the batteries are at least 97% full. :) |
| |
| Q4: What kind of batteries are there in my factory default Player/Recorder? |
| A4: Both ship with 1500 mAh NiMH (Nickel Metal Hydride) batteries. |
| |
| Q5: Is it hard to change the batteries? Does it void my warranty? |
| A5: It is not very hard - the Archos manual and the FAQ on their web site |
| describe how to do it. Their technical support confirmed that replacing |
| the batteries with NiMH cells (of different capacities) will not void the |
| warranty. Just don't remove the screws. |
| |
| Some units have been shipped with two sets of batteries, my Recorder 20 |
| only had one set. Someone actually had Archos send him new batteries free |
| of charge after they had weared out, under the warranty. |
| |
| Q6: How much do replacement batteries cost? Where can I buy them? |
| A6: http://www.greenbatteries.com sells 1800 mAh NiMH cells at $3.25USD each, |
| and I bought 4 of the same GP batteries for 20 euros in an home |
| electronics & household appliance store in Finland. NiMH batteries are |
| sold in almost all shops that sell consumer electronics, and in many |
| online shops. Browse around. There's a pretty good comparison between |
| different battery makes and models at the digital imaging resource site: |
| http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM In Germany, |
| www.reichelt.de sells GP 2000 batteries for 2,75 EUR (12/2002). |
| |
| Q7: What kind of run-time can I expect on a set of fully-charged batteries |
| when running Rockbox? |
| A7: For the stock 1500 mAh cells, from 6 hours to 8 hours, depending on which |
| charger was used (see Q3) and the bitrate you use (higher bitrate means |
| more harddisk runtime). It depends a lot on the condition of the |
| batteries. With 2000 mAh batteries, you should reach about 10 hours or |
| more. We are looking into implementing more battery-saving techniques in |
| rockbox to make it rock longer. If you have a modified AJB with 8 MB, you |
| can reach playing times of up to 16 hours with 2100 mAh batteries. |
| |
| Q8: Can I use different batteries in my Archos? How much playtime would |
| I gain by using 1800 mAh batteries instead of the 1500 mAh ones? |
| A8: Only use NiMH-type rechargeable batteries. It is considered to be safe to |
| use NiMH batteries of different capacities though, a lot of people have |
| purchaced 1700 or 1800 mAh batteries to replace the stock 1500 mAh cells |
| and have the device run a bit longer. 2000 mAh batteries are just |
| appearing in shops are equally good to use. |
| |
| In theory, running time = capacity of batteries / current drawn by device, |
| so running time should increase linearly by the capacity, and 2000 mAh |
| over 1500 mAh should give 33% longer running time. In practice, the mAh |
| ratings are more or less tuned up by the marketing department (think of |
| watts on the back of "hi-fi" speakers and amplifiers) and what you |
| actually get out of the cells is something else than what is printed on |
| them. Check the excellent imaging-resource link above for details! |
| |
| Q9: Can I use non-chargeable batteries in my Archos? |
| A9: This is not recommended. The unit has been designed to operate with four |
| 1.2V batteries producing about 4.8V at most, and using 1.5V alkaline/zinc |
| carbon batteries will produce around 6.0V, which will heat up the unit a |
| lot more and might even damage it. The Archos manual explicitly tells you |
| not to do so. Also, if you connect the charger, it may even destroy both |
| the batteries and the unit. |
| |
| Q10: Can I use a different charger? |
| A10: The short answer is: Using a different charger will void your warranty |
| and can be dangerous to your unit, so we can not recommend it. |
| |
| On the other hand, people have successfully used different chargers with |
| similar specifications as the stock charger. The charger must have the |
| same kind of connector with same polarity (center positive/+). The |
| charger should supply at least 7-8 volts, and if it provides more than |
| 10V, it probably should be regulated to 10V (do not directly plug it in |
| your 12V car battery or it's charger!). The universal travel charger |
| sold by Archos is specified at 12V, 1.2A so that's probably the maximum |
| rating you should use. A good circuit for powering from a car battery or |
| other source with a higher voltage would be a 600 mA fuse and a 10V |
| regulator like a 7810 of your favourite manufacturer in series. |
| |
| Inside the Jukebox there is a regulator which limits the charging current |
| applied to the batteries. The higher the input voltage, the hotter this |
| IC gets. Don't use an input voltage above 12V. Using lower charging |
| voltage < 10V will slow down the charging. But the rockbox charging |
| algorithm should work then, too. |
| |
| These are the output voltages of an original archos power supply: |
| - connected to AJB Recorder, not charging: 13,7 Volt |
| - connected to AJB Recorder, charging: going down to 10,4 Volt |
| |
| Here is how changing the input voltage changes the charging current: |
| |
| voltage charging current (limited only by the AJB) |
| ------------------------------------------------------ |
| 7,0V 10 mA |
| 7,5V 30 mA |
| 8,0V 50 mA |
| 8,5V 70 mA |
| 9,0V 140 mA |
| 9,5V 250 mA |
| 10,0V 330 mA |
| 10,5V 350 mA |
| 11,0V 350 mA |
| 11,5V 350 mA |
| 12,0V 350 mA |
| |
| To summarize: |
| |
| - do not use an input voltage > 12V (it will only heat up the regulator) |
| - optimal input voltage is 10V (regulated) |
| - use a fuse of ~600mA |
| - using a different charger voids your warrenty |
| |
| Many people are happy using an external quick charger which is specified |
| to work with NiMH batteries. This is completely safe and will not void |
| your warranty. |
| |
| Q11: Can I buy a replacement charger exactly as the one Archos shipped? |
| A11: The FAQ on the Archos web site and the top of the charger both read: |
| |
| Output: 9VDC 600mA |
| Center positive (+) polarity |
| |
| The universal travel charger sold separately on the Archos web site is |
| specified for 12VDC, 1200mA output. |
| |
| Chargers with similar (or user-adjustable) properties are available at |
| shops selling consumer electronics. |
| |
| Q12: I often need to stop my player for about 15 minutes or so, and when I do |
| it runs off it's batteries. I was wondering, which is best: shutting the |
| player down completely and rebooting it when I want to listen again, or |
| leaving the unit on? Which way does it draw more power? |
| A12: In our testing we found the following results: |
| HDD off, backlight off, idle 94 mA |
| HDD off, backlight off, play 97 mA |
| HDD off, backlight on, idle 129 mA |
| HDD off, backlight on, play 131 mA |
| HDD on, backlight on, play 230 mA |
| HD on, reading, backlight off ~ 600 mA |
| HD spin up before read max 800 mA |
| |
| Using the power draw measurements shown above, lets look at the numbers: |
| Power-down and restart vs. paused for 15 minutes.: |
| |
| Pause for 15 minutes will draw: 94 mA / 60 minutes * 15 minutes = |
| 23.5 mAh. |
| |
| Power-down and restart will draw about (800mA / 3600 seconds * 3 |
| seconds = 0.6666 mAh) + (600 mA / 3600 seconds * 6 seconds = 1.0 mAh) + |
| (230 mA / 3600 seconds * 8 seconds = 0.5111 mAh) = 2.18 mAh total used. |
| |
| Thus, leaving it paused for 15 minutes draws more power (23.5 mAh) than |
| turning off and then on again (2.18 mAh). |
| |
| So where is the break-even point? |
| |
| Each second of pause will draw about 94 mAh / 3600 seconds = 26 µAh. |
| |
| 2.18 mAh / 26 µAh = 2180 µAh / 26 µAh = 83.5 seconds |
| |
| Thus a shutdown and restart uses as much power as 83.5 seconds of pause. |
| |
| Q13: When I plug in the charger when the Recorder is turned off, it turns |
| itself on and starts charging in the Archos software? What's up? |
| A13: There is a switch in the DC IN jack of the Jukebox - when a charger (or |
| whatever) is plugged in, the unit is powered on, even if the charger is |
| not plugged in a mains outlet. |
| |
| If the charger is providing power at this point, the Archos firmware |
| located on the FLASH ROM does not load a new firmware version (like |
| Rockbox) from the disk, but goes into charging mode instead. You can use |
| this feature to get to the Archos charger if you want to. |
| |
| However, if you put Rockbox in flash, it will always charge with the |
| Rockbox charging algorithm. |
| |
| Q14: When I plug the charger in my Recorder, it doesn't immediately start |
| charging the batteries! |
| A14: When Rockbox is running on the Recorder (the device has been booted |
| without the charger) it's power management code runs once per minute |
| (thus the charge level and charging status is only updated every minute). |
| If the battery is not full, it will start charging. If the 'deep |
| discharge' mode is enabled in the settings menu, it will start charging |
| only when the battery is almost empty. |
| |
| Q15: What about the memory effect? Should I be worried about it or not? |
| A15: That depends on who you ask. ;-) NiMH sellers say NiMHs are better and do |
| not have a memory effect, but the usual opinion seems to be that they do, |
| although it is very small. |
| |
| However, if you use your AJB connected to the charger all the time, |
| we recommend you to use the deep discharge option. |
| |
| Q16: When I start my Jukebox, (dis)connect the charger and browse through the |
| directories, the battery level changes a little bit. Sometimes it's even |
| going up without the charger is connected! What's wrong? |
| A16: Nothing's wrong. The battery level is calculated out of the voltage. |
| Because disk spinning, LED backlight, charger all influence the actual |
| battery voltage, it is usual that the battery level is going a little bit |
| up and down sometimes. This cannot be avoided although we tried to make |
| the battery level display as little confusing as we could. |
| |
| Q17: My batteries are at 92%, the charger is connected to my recorder, deep |
| discharge is off. But charging doesn't start. What's wrong? |
| A17: Charging starts if the battery level is below 85%. This is because |
| charging batteries that *are* already more or less full is not good for |
| the batteries and the end of the charging cycle can't be detected safely. |
| So it's better to start at a level at least as low as 85%. If you want |
| to have full batteries in the morning, leave the charger connected over |
| night. Charging will then start some hours later. The second possibility: |
| Use the Archos charging algorithm. At least, your batteries will be full |
| one more time. ;-) |
| |
| Q18: Why does rockbox show a question mark for the battery level? |
| A18: Rockbox waits for about a minute to show a battery reading, to increase |
| the reliability of the reading. In previous versions, the battery level |
| rockbox initially reported was always too low. |