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<DIV><FONT face=Arial size=2>I have a little more complicated setup. An
Eagle Tree flight recorder with a telemetry down link. Before taking off I
run up the motor and read the voltage, current and rpm from the handheld
receiver. If everything looks good,away I go.</FONT></DIV>
<DIV><FONT face=Arial size=2>Recently I removed the system to use it on my test
stand. One day I was out putting in a flight every half hour. When I
went to charge one pack after my fifth flight I noticed it wouldn't switch out
of initial charge. After I read the TP charger manual I found out it was
supposed to stay in initial charge until it reached 37 volts and it was
definitely below. I started looking at my charge data and noticed I had
only put in 3200 mAh before that flight. At the time I hadn't looked at
the voltage and assumed I had just used less power on that flight as I was doing
a lot of horizontal stuff instead of the usual pattern. Bad.</FONT></DIV>
<DIV><FONT face=Arial size=2>I think you folks have convinced me to put the
Eagle Tree back in the plane.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Jim O</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=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">NSRCA Mailing List</A> </DIV>
<DIV style="FONT: 10pt arial"><B>Sent:</B> Wednesday, April 18, 2007 3:31
PM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion]
E-power</DIV>
<DIV><BR></DIV>
<DIV>A little more complicated, but for one of the 3S type planes that I fly,
I have an eLogger from Eagle Tree, with the optional LCD display. I see
the voltage when I plug up, check the current/watts when I run the motor
up, and see the max current, min voltage and consumed power (mah)
when I land. If I had an epower pattern plane, I would install one
without thinking twice about it. Besides the visual parameter display, it can
also log info for the whole flight so you can see the current that each
maneuver requires.</DIV>
<DIV> </DIV>
<DIV>The 3914 is a bargraph display driver. It can be wired as an expanded
scale meter which would work well for what we are doing. However, if a simple
"green light" type of voltage indicator was all I needed, I would probably
just use a simple op-amp or comparator set to just under the fully charged
battery voltage.</DIV>
<DIV> </DIV>
<DIV>Bob R.</DIV>
<DIV><BR><BR><B><I>Jay Marshall <lightfoot@sc.rr.com></I></B>
wrote:</DIV>
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<DIV class=MsoNormal><FONT face=Arial color=navy size=2><SPAN
style="FONT-SIZE: 10pt; COLOR: navy; FONT-FAMILY: Arial">I’m sure most of us
are familiar with the VoltWatch battery monitor. It uses a simple LM3914
integrated circuit from National Semiconductor. A nice visual indicator just
before takeoff. Seems to me that it could be easily modified, or even
re-designed, for the higher voltage packs the E-power guys are using. Any of
you EEs want to make a few bucks?</SPAN></FONT></DIV>
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