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<DIV><FONT face=Arial size=2>5 cell 1100mah NimH, they are 2/3AA cells. With a
long ( 7" ) heavy duty Futaba lead and shrink wrap you are looking at 3.4
ounces. They are available in a flat pack or two over three hump shaped pack
from Batteries of America/E.H.Yost Co. at <A
href="http://www.batteriesamerica.com/">http://www.batteriesamerica.com/</A></FONT></DIV>
<DIV><FONT face=Arial size=2><FONT face="Times New Roman" size=3>Ed
M.</FONT><BR></DIV></FONT>
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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=cjm767driver@hotmail.com href="mailto:cjm767driver@hotmail.com">Chris
Moon</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> Friday, May 07, 2004 9:57 PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Charging concerns/questions
with NMP Lithium Ion batteries</DIV>
<DIV><BR></DIV>Ed: I am running a 1450 nimh 5 cell pack at 5oz. I did
some rough calculations from my practice flights and figure an average flight
with 10min in the air plus start / taxi times the battery uses 200 mah per
flight. I am using 2- 8411's 2-9411's and a 331 servo. So the
1450mah is more than plenty and a 1050mah would work too and save a
little weight.<BR>Chris<BR><BR>Ed Deaver wrote:<BR>
<BLOCKQUOTE cite=mid20040508013404.4550.qmail@web11801.mail.yahoo.com
type="cite">
<DIV>OK, Ive had Duralite and subsequently Powerflites for about 5 years
now. Because of the fire hazard, everyone is recommending going back
to reg batteries or NMhd(which my charges probably won't support)</DIV>
<DIV> </DIV>
<DIV>So for 3 digital, 1 4721 and a mini throttle servo, how many mah should
I look at buying in old style batteries? I would only go with 5 cell
pack.</DIV>
<DIV> </DIV>
<DIV>Thanx</DIV>
<DIV> </DIV>
<DIV>ed<BR><BR><B><I>Keith Black <A class=moz-txt-link-rfc2396E
href="mailto:tkeithb@comcast.net"><tkeithb@comcast.net></A></I></B>
wrote:</DIV>
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<DIV><FONT face=Arial size=2>Thanks for your reply Jim. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>I do like design of the NMP charger and the
way it shows how much current is being feed to the battery. This is
clearly an excellent design feature. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>What I gather from your response is it is
"possible" for a cell to be charged beyond the safe limit if another cell
is either out of balance or defective. Also, I understand your point that
one may be able to spot a bad cell after becoming familiar with the
charger. </FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>As it relates to the cells being unbalanced,
will lithium batteries equalized each other via a "trickle" as is the case
with NiCad batteries?</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Jim, I really appreciate your always candid
responses and willingness to assist others on the list.</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Arial size=2>Thanks,</FONT></DIV>
<DIV><FONT face=Arial size=2>Keith</FONT></DIV></DIV>
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<DIV
style="FONT: 10pt arial; font-stretch: normal; font-size-adjust: none">-----
Original Message ----- </DIV>
<DIV
style="BACKGROUND: rgb(228,228,228) 0% 50%; FONT: 10pt arial; font-stretch: normal; font-size-adjust: none; moz-background-clip: initial; moz-background-inline-policy: initial; moz-background-origin: initial"><B>From:</B>
<A title=JOddino@socal.rr.com
href="mailto:JOddino@socal.rr.com">JOddino</A> </DIV>
<DIV
style="FONT: 10pt arial; font-stretch: normal; font-size-adjust: none"><B>To:</B>
<A title=discussion@nsrca.org
href="mailto:discussion@nsrca.org">discussion@nsrca.org</A> </DIV>
<DIV
style="FONT: 10pt arial; font-stretch: normal; font-size-adjust: none"><B>Sent:</B>
Friday, May 07, 2004 10:30 AM</DIV>
<DIV
style="FONT: 10pt arial; font-stretch: normal; font-size-adjust: none"><B>Subject:</B>
Re: Charging concerns/questions with NMP Lithium Ion batteries</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Hi Kieth,</FONT></DIV>
<DIV><FONT face=Arial size=2>I believe the NMP solves most of the
problems we have all read about. 1) it is the right type of
charger for Li-Ions and is dedicated to that chemistry by limiting the
current and the voltage. 2) it is set for two-cell packs and that cannot
be changed by the operator or on its own. 3) it limits the current to
less than the 1C rate (for 2000 mAh packs).</FONT></DIV>
<DIV><FONT face=Arial size=2>Probably its best feature vs. the
other chargers is the meter that tells the operator what is going
on. After you use it a few times you will be able to predict the
current at the beginning and during the charge cycle depending
on how many flights you had. If something is wrong, like a cell
way out of wack, it will give you an indication. Of course it
tells you when the pack is charged and if for some reason it was taking
too long you would figure it out. In other words you will learn
what is normal proper charge current vs. time and could spot an
unbalanced pack. It cannot assure you a cell will not be
overcharged if the cells are not matched but I believe you would spot
it.</FONT></DIV>
<DIV><FONT face=Arial size=2>I've been using it for over a year and
always charge the packs in the plane. The total charge time is
relatively short so you can monitor it, but I have left them plugged in
over night. </FONT></DIV>
<DIV><FONT face=Arial size=2>I have only seen one pack (a Duralite which
was in a plane I bought) with a slight unbalance. It was a 2S2P
configuration and I don't have much experience with that
configuration. I have never seen a simple 2 cells in series pack
unbalanced.</FONT></DIV>
<DIV><FONT face=Arial size=2>Where you really need to worry about this
is in long strings like those used in electric flight. I talked to
Fred Marks (FMA) about bringing out each node so each cell could be
checked and charged individually if required. He said they plan to
do that in the future.</FONT></DIV>
<DIV><FONT face=Arial size=2>In the mean time, I believe one could stick
a pin through the heat shrink to check the cell balance. I'll try
that today and get back to the list.</FONT></DIV>
<DIV><FONT face=Arial size=2>Regards,
Jim</FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>