docs/BATTERY-FAQ - rockbox - Gitiles

 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: The charger logic lets the batteries charge until they are full. After
     that, the charger is disabled, but 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). After some time, it will
     start charging the batteries again to keep them full. This will
     wear the batteries a little, but overnight charging is what most
     people do.

     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 current release of 1.2 is much worse than the Archos
     charger, it tends to stop charging much too early and leave the batteries
     half empty.

     The current development code (CVS daily builds as of 20.8.2002) is much
     better than the 1.2 release, but still not perfect. Linus recently
     measured 6 hours continuous playtime after a rockbox charge, and much
     over 7 hours after an Archos charge. We are working on fine-tuning
     the charger logic to get the most out of the batteries, but the
     emphasis is on not overcharging them, since that would damage the
     batteries. Better be safe than sorry.

 Q4: What kind of batteries are there in my factory default Player/Recorder?
 A4: Both ship with 1500 mAh NiMH (Nickel Metal Hybride) batteries.

 Q5: Is it hard to change the batteries? Does it void my warranty?
 A5: The archos manual and web site describe how to replace the batteries,
     so you're supposed to do it. They recommend using only Archos-supplied
     batteries, but my Recorder 20 unit only shipped with one set. Some
     units have been shipped with two sets of batteries. Someone actually had
     Archos send him new batteries free of charge after they had weared out,
     under the warranty. (have asked from support-technique@archos.com,
     waiting for an answer to arrive!)

 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

 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). It depends a lot on the condition of
     the batteries. We are looking into implementing more battery-saving
     techniques in rockbox to make it rock longer.

 Q8: Can I use different batteries in my Archos?
 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.

 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.

 Q10: Can I use a different charger?
 A10: 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 9V, it probably should be current limited (do not
      directly plug it in your 12V car battery or it's charger!).

      Using lower charging voltage will slow down the charging, and using
      higher voltage will cause a higher charging current, more heat,
      and too much heat and current can damage the batteries or the unit.
      Using a different charger will void your warranty and can be
      dangerous to your unit, so we can not recommend it.

      Many people are happy using an external quick charger which
      is specified to work with NiMH batteries.

 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

      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, LED off, idle 94 mA
          HDD off, LED off, play 97 mA
          HDD off, LED on, idle 129 mA
          HDD off, LED on, play 131 mA
          HDD on, LED on, play 230 mA
          HD on, reading, LED off ~ 600 mA
          HD spin up before read max 800 mA

      So leaving the unit on and paused consumes ~100mA, and thus much less
      than needing to reboot the unit.  Your mileage may vary.

 Q13: When I plug the charger in my Recorder, it doesn't immediately start
      charging the batteries. And 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.

      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.
	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: The charger logic lets the batteries charge until they are full. After
	that, the charger is disabled, but 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). After some time, it will
	start charging the batteries again to keep them full. This will
	wear the batteries a little, but overnight charging is what most
	people do.

	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 current release of 1.2 is much worse than the Archos
	charger, it tends to stop charging much too early and leave the batteries
	half empty.

	The current development code (CVS daily builds as of 20.8.2002) is much
	better than the 1.2 release, but still not perfect. Linus recently
	measured 6 hours continuous playtime after a rockbox charge, and much
	over 7 hours after an Archos charge. We are working on fine-tuning
	the charger logic to get the most out of the batteries, but the
	emphasis is on not overcharging them, since that would damage the
	batteries. Better be safe than sorry.

	Q4: What kind of batteries are there in my factory default Player/Recorder?
	A4: Both ship with 1500 mAh NiMH (Nickel Metal Hybride) batteries.

	Q5: Is it hard to change the batteries? Does it void my warranty?
	A5: The archos manual and web site describe how to replace the batteries,
	so you're supposed to do it. They recommend using only Archos-supplied
	batteries, but my Recorder 20 unit only shipped with one set. Some
	units have been shipped with two sets of batteries. Someone actually had
	Archos send him new batteries free of charge after they had weared out,
	under the warranty. (have asked from support-technique@archos.com,
	waiting for an answer to arrive!)

	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

	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). It depends a lot on the condition of
	the batteries. We are looking into implementing more battery-saving
	techniques in rockbox to make it rock longer.

	Q8: Can I use different batteries in my Archos?
	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.

	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.

	Q10: Can I use a different charger?
	A10: 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 9V, it probably should be current limited (do not
	directly plug it in your 12V car battery or it's charger!).

	Using lower charging voltage will slow down the charging, and using
	higher voltage will cause a higher charging current, more heat,
	and too much heat and current can damage the batteries or the unit.
	Using a different charger will void your warranty and can be
	dangerous to your unit, so we can not recommend it.

	Many people are happy using an external quick charger which
	is specified to work with NiMH batteries.

	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

	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, LED off, idle 94 mA
	HDD off, LED off, play 97 mA
	HDD off, LED on, idle 129 mA
	HDD off, LED on, play 131 mA
	HDD on, LED on, play 230 mA
	HD on, reading, LED off ~ 600 mA
	HD spin up before read max 800 mA

	So leaving the unit on and paused consumes ~100mA, and thus much less
	than needing to reboot the unit. Your mileage may vary.

	Q13: When I plug the charger in my Recorder, it doesn't immediately start
	charging the batteries. And 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.

	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.