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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=BUDDYonRC@aol.com
href="mailto:BUDDYonRC@aol.com">BUDDYonRC@aol.com</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> Sunday, August 31, 2003 12:50
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: Lithium or Not ?</DIV>
<DIV><BR></DIV>
<DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial color=#8000ff size=2
FAMILY="SANSSERIF">Jim or anyone else who can shed light on the subject<BR>Jim
Questions on your "Lithium Yes" post<BR>1. Why is a system with a regulator
better? A system without one has one less point of failure. and the radio
airborne fail-safe system works unregulated @ 4.8 volts. It does not work at
higher voltage since when you get to the fail-safe voltage the batteries are
discharged beyond the point of being able to operate. Fail-safe trip point is
4.3 volts on my radio.<BR></FONT></FONT></DIV>
<DIV><FONT lang=0 FAMILY="SANSSERIF"><FONT face="Arial Black" color=#8000ff
size=2>In a pattern plane we want consistency. That is why we practice
and practice. We want to fly the same perfect flight every
flight. There are some variables like wind and sun that we can't do much
about, but we can get consistent servo performance by using a regulator.
Without one the speed and available torque drop along with voltage. High
speed and high torque are desirable things in a servo so we want all we can
get without burning up the servo. The way to get it is start with a high
voltage and regulate to the maximum the servo can stand.</FONT></DIV></FONT>
<DIV><FONT face=arial,helvetica><FONT lang=0 face=Arial color=#8000ff size=2
FAMILY="SANSSERIF">2. I agree<BR>3.I agree<BR>4. How is it less complicated
than a Sirus charger with NiCads? One hour charge with a Sirus charger and 4
cell NiCad pack and it is fully charged.</FONT></FONT></DIV><FONT
face=arial,helvetica><FONT lang=0 face=Arial color=#8000ff size=2
FAMILY="SANSSERIF"></FONT></FONT></BLOCKQUOTE>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"><FONT
face=arial,helvetica><FONT lang=0 face=Arial FAMILY="SANSSERIF"><FONT
face="Arial Black" color=#8000ff size=2>The Sirius charger is relatively
complicated. It detects a deflection in the slope of the charge curve to
decide when to terminate the charge. the batteries must get hot in order
to create the change in slope so the whole process is temperature
sensitive. Two bad things can happen. It can miss the deflection
and overcharge or it can get a false alarm and turn off prior to a full
charge. You only have LEDs to tell you what happened and you must trust
them. It is also expensive and the one I have only charges at 500 mA
which I do not consider a fast field charger. It is a good charger but
it is a tough task to charge fast and terminate properly under various
environments. Charging Li-Ions is much easier with much less of a chance
of a screw up. </FONT>
<DIV><BR><FONT color=#8000ff size=2>5. How is the remaining charge predicted?
Are they cycled down to assure the capacity the same as
NiCad's?</FONT></DIV><FONT color=#8000ff
size=2></FONT></FONT></FONT></BLOCKQUOTE>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"><FONT
face=arial,helvetica><FONT lang=0 face=Arial FAMILY="SANSSERIF"><FONT><FONT
face="Arial Black" color=#8000ff size=2>There is a very close relationship
between the loaded voltage and remaining charge and therefore you can use more
of the charge with confidence that you are not near the knee of the
curve. You do need to run a discharge curve to know what to expect from
your battery just like NiCds.</FONT>
<DIV><BR><FONT color=#8000ff size=2>6. "Less maintenance. No cycling." If this
is true how is the actual capacity of the pack determined?</FONT></DIV><FONT
color=#8000ff size=2></FONT></FONT></FONT></FONT></BLOCKQUOTE>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"><FONT
face=arial,helvetica><FONT lang=0 face=Arial FAMILY="SANSSERIF"><FONT><FONT
color=#8000ff><FONT face="Arial Black" size=2>You do need to run one cycle
when you get them. I'd also do one every six months to see how they are
holding up.</FONT><FONT color=#000000></FONT>
<DIV><BR><FONT size=2>7. OK<BR>8. Isn't that true of any system? If not
why?</FONT></DIV><FONT size=2></FONT></FONT></FONT></FONT></FONT></BLOCKQUOTE>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"><FONT
face=arial,helvetica><FONT lang=0 face=Arial FAMILY="SANSSERIF"><FONT><FONT
color=#8000ff><FONT size=2><FONT face="Arial Black">Let's take your system
with a four cell pack. At high current the voltage at the pack will drop
due to the internal resistance of the batteries, there will be a voltage drop
in the connectors, wire and switch and you could easily get less than 4.3
volts at the receiver bus. Therefore people are going to heavier and
heavier wire and switches. We are kind of stuck with the connectors but
some folks are using heavier connectors on the battery and switches. My
new plane will have a regulator (which can be inexpensive) at every servo so I
don't care if there is a voltage drop in the cabling.</FONT> <FONT
face="Arial Black"> You wouldn't need this in a typical pattern plane where
the servos plug directly into the receiver but in the big stuff you can get
some long cable runs and multiple servos on one channel.</FONT></FONT><FONT
color=#000000></FONT>
<DIV><BR><BR><FONT size=2>Back to my original question, Do Li-Ion packs have a
circuit breaker built in?</FONT></DIV><FONT
size=2></FONT></FONT></FONT></FONT></FONT></BLOCKQUOTE>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"><FONT
face=arial,helvetica><FONT lang=0 face=Arial
FAMILY="SANSSERIF"><FONT><FONT><FONT face="Arial Black" color=#8000ff
size=2>Powerflite had them initially but took them out. Duralite has
something on the charge circuit but not on the output as far as I know.
We don't want any packs with a circuit breaker in it, in my
opinion.</FONT>
<DIV><BR><FONT color=#8000ff size=2>Do they Contrary to NiCad's fail open?
</FONT></DIV><FONT color=#8000ff
size=2></FONT></FONT></FONT></FONT></FONT></BLOCKQUOTE>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"><FONT
face=arial,helvetica><FONT lang=0 face=Arial
FAMILY="SANSSERIF"><FONT><FONT><FONT><FONT face="Arial Black" color=#8000ff
size=2>I am not aware of any open failures but I suppose it could happen as
often as it does in NiCds.</FONT>
<DIV><BR><FONT color=#8000ff size=2>Just trying to sort out the reasons that I
should consider going this way over NiCads that I have been using for years
without a problem.</FONT></DIV><FONT color=#8000ff
size=2></FONT></FONT></FONT></FONT></FONT></FONT></BLOCKQUOTE>
<BLOCKQUOTE
style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px"><FONT
face=arial,helvetica><FONT lang=0 face=Arial
FAMILY="SANSSERIF"><FONT><FONT><FONT><FONT><FONT face="Arial Black"
color=#8000ff size=2>No problem. Keep asking questions and make your own
decisions.</FONT>
<DIV><BR><FONT color=#8000ff
size=2>Buddy</FONT></FONT></FONT></FONT></FONT></FONT>
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