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Re: Why not NiMH?

From J Burns <burns4@nowhere.com>
Newsgroups comp.sys.mac.system
Subject Re: Why not NiMH?
Date 2013-12-05 03:08 -0500
Organization A noiseless patient Spider
Message-ID <l7pc9i$rjd$1@dont-email.me> (permalink)
References <l7o6ih$a9r$1@dont-email.me> <mcmurtrie-3766AD.23082204122013@c-61-68-245-199.per.connect.net.au>

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On 12/5/13 2:08 AM, Kevin McMurtrie wrote:
> In article <l7o6ih$a9r$1@dont-email.me>, J Burns <burns4@nowhere.com>
> wrote:

> You're mistakenly comparing only amp-hours.  NiMH have an average output
> of just 1.1 volts per cell while LiPo is 3.7 volts per cell.  That makes
> the watt-hours per volume much higher for LiPo.  Compare watt-hours per
> weight and NiMH starts to look like a very bad idea.  The little 13"
> MacBook Pro has 71 watt-hours of batteries inside.  That would be about
> the power of 30 top-quality AA sized NiMH cells.

I was thinking of watt-hours. According to Wikipedia, the energy density 
of lithium polymer batteries is 300 Wh/L.  The energy density of NiMH is 
140-300 Wh/L.

Wikipedia says LiPo produces 130-200 Wh/kg, and NiMH produces 60-120 
Wh/kg.

One thing I used to dislike about NiMH was that sometimes the voltage 
under a load was only 1.1.  Eneloops do much better.
>
>
> NiMH cells are also a major pain in the ass to charge properly.  It can
> only be done with a very steady current and a very steady temperature so
> that a very tiny voltage dip may be detected.  Any other conditions
> require a powerful overcharge so that rapid heating may be used for
> detection.  It doesn't work well in a laptop.  LiPo can be charged to
> 80% capacity with a constant float voltage or charged to 100% with a
> straightforward top-off algorithm.  It's much easier.
>
My charger has a circuit for each cell.  It charges Eneloop AAs at 
2000ma, a much higher rate than NiMH cells used to accept.  I use them 
mostly for a one-cell headlamp.  With 1500ma, it will light a wall 500 
feet away.  I couldn't get that kind of power from the NiMH cells 
available in the past.  Normally I run it at 450ma and get about 4-1/2 
hours.  The NiMH cells available in the past didn't give me such 
consistent run times.

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Thread

Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-04 16:24 -0500
  Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-04 16:38 -0500
    Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-05 11:01 +1100
      Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-04 23:38 -0500
        Re: Why not NiMH? Mike Lane <mike.lane.usenet@ntlworld.co.uk> - 2013-12-05 13:21 +0000
          Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 11:29 -0500
          Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 09:01 +1300
      Re: Why not NiMH? Davoud <star@sky.net> - 2013-12-05 05:21 -0500
        Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 09:07 +1100
          Re: Why not NiMH? Davoud <star@sky.net> - 2013-12-05 18:42 -0500
            Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 11:57 +1100
              Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 18:34 +1300
                Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 17:08 +1100
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 19:19 +1300
                Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 20:14 +1100
          Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 13:30 +1300
            Re: Why not NiMH? dorayme <dorayme@optusnet.com.au> - 2013-12-06 12:00 +1100
              Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 18:24 +1300
            Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-05 19:50 -0600
      Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 15:11 -0500
        Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 16:15 -0500
    Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-04 19:59 -0500
      Re: Why not NiMH? Ted Lee <tmplee@mr.net> - 2013-12-04 22:09 -0600
        Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-04 23:38 -0500
        Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 00:54 -0500
          Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 00:59 -0500
            Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 02:22 -0500
              Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 02:44 -0500
                Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 03:36 -0500
                Re: Why not NiMH? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2013-12-05 04:21 -0500
                Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 11:29 -0500
                Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 16:24 -0500
              Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-05 18:37 +0000
                Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 14:19 -0500
                Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-05 13:31 -0600
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 09:07 +1300
                Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 14:36 -0500
                Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-05 22:02 +0000
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 13:26 +1300
                Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-06 00:33 +0000
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 18:36 +1300
                Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-06 21:22 +0000
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-07 11:49 +1300
                Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-07 00:11 +0000
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-07 18:07 +1300
                Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-07 08:37 -0600
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-08 09:52 +1300
                Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-05 19:49 -0600
                Re: Why not NiMH? JF Mezei <jfmezei.spamnot@vaxination.ca> - 2013-12-05 21:55 -0500
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-06 18:40 +1300
                Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-06 21:24 +0000
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-07 11:49 +1300
                Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-06 18:43 -0500
                Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-07 08:32 -0600
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-08 09:50 +1300
                Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-07 15:50 -0600
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-08 14:04 +1300
                Re: Why not NiMH? George Kerby <ghost_topper@hotmail.com> - 2013-12-07 21:02 -0600
                Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-08 17:45 +1300
                Re: Why not NiMH? Lewis <g.kreme@gmail.com.dontsendmecopies> - 2013-12-06 17:48 +0000
                Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-06 21:25 +0000
        Re: Why not NiMH? Davoud <star@sky.net> - 2013-12-05 05:33 -0500
        Re: Why not NiMH? Jolly Roger <jollyroger@pobox.com> - 2013-12-05 18:35 +0000
      Re: Why not NiMH? Zar Zifodow <zarzifodow@mailinator.com> - 2013-12-04 20:14 -0800
      Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-04 23:38 -0500
        Re: Why not NiMH? Siri Cruz <chine.bleu@yahoo.com> - 2013-12-04 20:46 -0800
        Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 02:22 -0500
          Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 02:44 -0500
  Re: Why not NiMH? Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2013-12-04 23:08 -0800
    Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 03:08 -0500
      Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 11:29 -0500
  Re: Why not NiMH? me@home.spamsucks.ca (Király) - 2013-12-05 14:15 +0000
    Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-05 12:43 -0500
      Re: Why not NiMH? nospam <nospam@nospam.invalid> - 2013-12-05 12:54 -0500
      Re: Why not NiMH? Kevin McMurtrie <mcmurtrie@pixelmemory.us> - 2013-12-05 22:44 -0800
        Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-06 13:19 -0500
      Re: Why not NiMH? me@home.spamsucks.ca (Kiraly) - 2013-12-06 22:35 +0000
        Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-07 02:27 -0500
        Re: Why not NiMH? J Burns <burns4@nowhere.com> - 2013-12-08 00:10 -0500
  Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-14 18:57 +1300
    Re: Why not NiMH? Fred Moore <fmoore@gcfn.org> - 2013-12-17 12:04 -0500
      Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-18 09:27 +1300
  Re: Why not NiMH? Your Name <YourName@YourISP.com> - 2013-12-19 18:59 +1300

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