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<DIV><FONT face=Arial size=2>I would second what Earl wrote about NiMh's
and add that I have been using Li-ion's in my planes for several years. They
charge up in around 2 hours from my cigarette lighter using a central hobbies
charger (NMP/Jim O).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Most importantly you can top them up at any time.
Before you fly, between flights etc. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Most times I recharge on the way home and
they are still ready to use (Fully charged) a week later.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Eric.</FONT></DIV>
<DIV> </DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=ehaury@houston.rr.com href="mailto:ehaury@houston.rr.com">Earl
Haury</A> </DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, October 06, 2005 10:28
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Airborne batteries</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Bob</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>NiMH & Li are both viable and offer
advantages over NiCad in capacity, maintenance, and weight. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>The internal impedance of the present day NiMH
results in slightly more voltage drop for a given current than NiCad (or Li),
but the price / capacity / weight value is hard to beat. Mechanical
durability is as good as NiCad. I use a Sanyo 1650 mah 5 cell pack (5
cells to minimize the volt drop effect) with a regulator ) <$20 &142
gr. I've logged more than 1000 flights on these with no problems (generally
renew the pack annually). I use the same cells in my xmtr.
Slow charging is no problem except that the higher capacity takes longer if
they're discharged fully. The advantages over Li are cost and the acceptance
of fast charging. Some peak detect fast chargers don't do well with NiMH, I've
found the Sirius Pro to be excellent.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>However, I am changing to Li (the hard case of
the Li-ion makes them a bit more mechanically durable than LiPo). Low
impedance provides minimal voltage drop at high current loads. The real
advantage is the weight / capacity ratio, a 2400 mah Li-ion weighs less than
100 gr. with even less weight for LiPo. The disadvantages are that
a volt reg is necessary, their inability to accept fast charging,
and higher cost. I use the NMP charger from Central (Jim Oddino designs are
reliable). </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Earl</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
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<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=bob@toprudder.com href="mailto:bob@toprudder.com">Bob Richards</A>
</DIV>
<DIV style="FONT: 10pt arial"><B>To:</B> <A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Thursday, October 06, 2005 7:40
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Airborne batteries</DIV>
<DIV><BR></DIV>
<DIV>Guys,</DIV>
<DIV> </DIV>
<DIV>I'm needing to replace several nicad airborne packs for my radios (as
well as a couple of transmitter packs). I'm wondering what has changed in
the technology in the past 8 years. </DIV>
<DIV> </DIV>
<DIV>NiMh packs had just hit the market about 10 years ago, and as I recall
it seemed that they did not stand up well to vibration - several inflight
failures being reported. Seemed they were ok for transmitters. Has that
changed?</DIV>
<DIV> </DIV>
<DIV>I know Li-ion and Li-poly are now available, but what type of charging
apparatus am I looking at investing in? I also think I need to use a
regulator with these?</DIV>
<DIV> </DIV>
<DIV>I don't presently have a fast field charger and would like to have one,
is there one that covers all the above bases?</DIV>
<DIV> </DIV>
<DIV>Thanks in advance,</DIV>
<DIV> </DIV>
<DIV>Bob Richards.</DIV></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>