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10501Re: [tracker2] T2-301 power supply

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  • Tim Cunningham
    May 9 10:19 PM
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      Forget about Alkaline.

      Here is a nice reference to some NiMH batteries and chargers for reference
      you might find helpful, but it is a little dated:

      http://www.imaging-resource.com/ACCS/BATTS/BATTS.HTM


      I have tested a few brands myself (NiMH variety) and found that none lived
      up to their actual ratings. Chargers and batteries have been a variable in
      my digital camera operation. I finally tossed my charger and upgraded to a
      more elaborate charger and it indeed made a huge difference in how I group
      my batteries for camera/flash operation. Some batteries come close to their
      rated numbers as far as capacity (NiMH type) but I have not seen many in my
      experience. It only takes one bad link in a chain to cause trouble as well.
      So, the condition of any battery and its storage capability are important
      when used in series. I once had some Camedia batteries that really performed
      many years ago and they lasted the longest as far as the number of recharge
      cycles. History has not repeated in this area. Manufacturers change their
      recipe from time to time and you cannot expect the same brand to perform the
      same either as new batteries are released. I have thrown many of the
      Duracell 2600mah batteries away due to high impedance failures or failure to
      live up to the rated capacity. I have been pleased with PowerEx so far, but
      I just started using their products in the past 6 months.

      I have a Maha MH-C9000 charger that I have been very pleased with using to
      keep my batteries in good condition and report the health by analyzing the
      batteries. This has proved its worth many times to keep my camera and flash
      running on extended periods. I carry several sets of batteries grouped
      according to their actual (not rated) storage capacity. It makes enough
      difference to do this when you need reliable and repeatable performance.

      Lithium's will be the best bet.

      All rechargeables need to be topped off or recharged before prior to use due
      to shelf life limitations if you want/need/demand maximum performance. For
      critical operation you need to analyze your batteries (put them to the test)
      before you put them into operation to avoid any surprises.


      73's,

      Tim - N8DEU



      ----- Original Message -----
      From: "Jason KG4WSV" <kg4wsv@...>
      To: <tracker2@yahoogroups.com>
      Sent: Sunday, May 09, 2010 4:46 PM
      Subject: Re: [tracker2] T2-301 power supply


      > On Sun, May 9, 2010 at 4:24 PM, Bob Burns W9RXR <w9rxr_@...>
      > wrote:
      >
      >> Duracell alkaline AA cells are rated at 1.5 volts and around 2800 mAH
      >> (is this number correct?)
      >
      > sounds a bit high to me - that's the spec for the energizer AA lithium.
      >
      > Alkaline batteries don't like high current draws. I think alkalines
      > are a losing proposition.
      >
      > I either can't find my notes or failed to take any, but IIRC an 8 pack
      > of energizer AA lithium will run a T2-301 at default power (5W)
      > beaconing once a minute for at least 24 hours. A 4 pack of CR123A
      > cells (3V lithium camera battery) will go over 12 hours (12 was the
      > duration of the test, batteries were not dead at the end of the test).
      >
      > It depends on how long and how frequently you want to operate. If
      > this is for ballooning or emergency use, e.g. SAR (note: I am not an
      > SAR person), for example, I think lithium batteries would be better.
      > They are zero maintenance, high capacity, cold-tolerant, and have a
      > long shelf life. Rechargeables, on the other hand, require regular
      > maintenance - they don't like to sit around discharged, so you need to
      > charge them occasionally even if you aren't using them.
      >
      > I vaguely recall some discussion here about the minimum voltage for
      > the T2-301. I do recall seeing a 7808 regulator when I opened up the
      > one that landed in the river, so there's a minimum of 8.6V for
      > reliable operation. The actual lower limit may be higher than that.
      >
      > -Jason
      > kg4wsv
      >
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