<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=Content-Type content="text/html; charset=iso-8859-1">
<META content="MSHTML 6.00.2800.1400" name=GENERATOR></HEAD>
<BODY bgColor=#ffffff>
<DIV><FONT face=Arial size=2>If you simply remove it and keep an eye on it while
charging, you'll probably have no problems. Awareness is the whole issue, unlike
what some other people seem to think. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Sorry, but I think I'm fresh out of
restraint.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>-Mike</FONT></DIV>
<DIV> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=tkeithb@comcast.net href="mailto:tkeithb@comcast.net">Keith Black</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 10:20 PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Charging concerns/questions
with NMP Lithium Ion batteries</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Ed,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>In my current Aries I run two NiMH battery packs,
the new Li-Ion packs were "going" to go into my new plane.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Here's my current setup: One five cell double A
1680 mah NiMH pack (5.2 oz.) on a 5.7 volt regulator, and one five cell triple
A 400 mah NiMH pack (about 2.5 oz) on a 5.4 volt regulator. Power is
always pulled from the 1680 mah pack unless it drops below 5.4 volts.
Therefore, the 400 mah battery only kicks in if needed (due to a failure or
dead primary pack). </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I can fly until I'm tired on the fully charged
1680 mah pack, I'm guessing safely 6 or more 20 minute flights.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>I derive a level of comfort from having the
redundant battery setup after hearing all the horror stories and seeing
Lance's beautiful Aries #2 go in due to lost receiver power.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>With my current setup I'm carrying around almost
eight ounces of battery weight, which is why the Li-Ions looked good to me. I
could drop 1.8 oz by going to the Li-Ion batteries AND increase flying time
(though flying time isn't an issue).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>However, given the issues with Li-Ion packs I
feel that I should either A) stick with my NiMH batteries or, B) install the
Li-Ion in a location that it can be removed for each charge.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Keith Black</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=divesplat@yahoo.com href="mailto:divesplat@yahoo.com">Ed Deaver</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 8:34
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Charging
concerns/questions with NMP Lithium Ion batteries</DIV>
<DIV><BR></DIV>
<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 <tkeithb@comcast.net></I></B>
wrote:</DIV>
<BLOCKQUOTE class=replbq
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">
<META content="MSHTML 6.00.2800.1400" name=GENERATOR>
<STYLE></STYLE>
<DIV>
<DIV><FONT face=Arial size=2>Thanks for your reply Jim. </FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </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><FONT face=Arial size=2></FONT> </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><FONT face=Arial size=2></FONT> </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><FONT face=Arial size=2></FONT> </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><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Thanks,</FONT></DIV>
<DIV><FONT face=Arial size=2>Keith</FONT></DIV></DIV>
<BLOCKQUOTE dir=ltr
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style="FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV
style="BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"><B>From:</B>
<A title=JOddino@socal.rr.com
href="mailto:JOddino@socal.rr.com">JOddino</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 10:30
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Charging
concerns/questions with NMP Lithium Ion batteries</DIV>
<DIV><FONT face=Arial size=2></FONT><FONT face=Arial
size=2></FONT><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><FONT face=Arial
size=2></FONT></DIV></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BLOCKQUOTE></BODY></HTML>