Rockbox mail archiveSubject: Re: Making progress - but more battery life questions
Re: Making progress - but more battery life questions
From: Michael O'Quinn <michael_at_oquinn.info>
Date: Thu, 21 Aug 2003 18:10:03 -0700 (PDT)
On Thu, 21 Aug 2003, Sharon wrote:
> Well, that isn't quite as easy to do as I expected, Jean - you are
> much faster than I am! Boy are those batteries hard to get out! I
> really had to work at the bottom ones; they seemed like they were
> glued in there. And I must have inadvertently turned the unit on 4-5
> times trying to get the ones on the left side out and hitting the on
> button accidentally.... Maybe I'll get faster with practice???
With my player I found it awkward at first, but now it's so automatic I
don't even think about it. And since I lost the charger recently camping
-- actually, while unpacking the car from camping, it was plugged in to
the charger when we pulled in to our driveway -- I have to change them
> I am assuming that if the battery indicator is getting low I can
> change them during a break even if it hasn't stopped playing because
> they're all the way dead?
> And then when I get home, I can recharge
> them in an external charger that discharges first so they're all the
> way dead before being recharged?
Well, it really isn't necessary to discharge them first. These are NiMHs
not NiCads, so they don't have nearly the memory problem. NiMHs do have
SOME memory, but it is fairly minimal. You can do a full discharge every
10 or 20 cycles if you want. Doing a full discharge every cycle is more
likely to simply wear out the batteries sooner without much benefit on run
> Is it true that higher bitrate files take more battery power? This
> audiobook was only 32 bitrate, so if I listen to one that is 96
> bitrate the batteries will last 1/3 the amount of time? I hope that
> isn't the case; hopefully it's not a direct math calculation like
You should definitely see longer run times at lower bitrates. It's tricky
computing EXACTLY how much longer.
According to Q: 12 of the battery FAQ, just sitting idle with the light
and HD off and not playing takes 94 mA, and 97mA while actually playing.
Spinning up the HD takes 800 mA for a brief period, and then reading takes
600 mA, while just letting it spin takes 230mA.
In normal playing, the biggest power hit is periodically spinning up the
HD and reading in order to re-fill the electronic buffer. The higher the
bitrate, the more often the disk must spin up. Your calculation would be
more reasonable if you were to factor in the approximately 97 mA used
between disk spinups. You could measure how long the disk spins each
time, and do the math.
Without taking the unit apart and actually measuring the current, you will
not know exactly how much current the HD is drawing at any given moment.
Also, different disks require differing amounts of power, so the number
given in the FAQ are really only a guide. Also, if you have a Recorder or
FMR instead of a player, the HD-Non-Spinning numbers may differ. In other
words, the only really reliable way of determining run-time is to actually
test it. See how long it plays at 32kbps bitrate, then again at 96 kbps.
> Thanks for ALL the help on this list!
> >1. I use the resume function too and when I change batteries, it
> >resumes where I left it.
> >2. The only tools you need to change batteries are your nails (my
> >very short ones do the job): place your Archos on your lap
> >crosswise, insert the nails of both thumbs under the little bumps in
> >front of the lid on the side away from you, push the lid gently away
> >from you and lift up. This takes less than one second each.
Received on 2003-08-22