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<DIV><FONT size=3 face=Calibri>Along the lines of taking advantage of better
batteries, ESC's could compensate for packs as they flatten out.
Essentially, an ESC could be designed to automatically de-rate the battery when
it is above a prescribed level of charge. I don't really keep up with what
the various ESCs have feature-wise, but I haven't heard of this being done
yet. I don't think it would be hard either. Effectively, it's like a
built-in ATV that simply limits the pulse width at full power when the battery
is above a certain level, just as it already does in response to throttle
inputs. There's an advantage to this in that the battery pack &
wiring arrangement stays simple and that all cells in the pack get used
simultaneously. I still like Jim's original idea, especially
because it got some more thinking on the topic going.</FONT></DIV>
<DIV><FONT size=3 face=Calibri></FONT> </DIV>
<DIV><FONT size=3 face=Calibri>Ed</FONT></DIV>
<DIV><BR></DIV>
<DIV style="FONT: 10pt Tahoma">
<DIV style="BACKGROUND: #f5f5f5">
<DIV style="font-color: black"><B>From:</B> <A title=AtwoodDon@aol.com
href="mailto:AtwoodDon@aol.com">AtwoodDon@aol.com</A> </DIV>
<DIV><B>Sent:</B> Monday, March 01, 2010 8:01 PM</DIV>
<DIV><B>To:</B> <A title=nsrca-discussion@lists.nsrca.org
href="mailto:nsrca-discussion@lists.nsrca.org">nsrca-discussion@lists.nsrca.org</A>
</DIV>
<DIV><B>Subject:</B> Re: [NSRCA-discussion] Max volts</DIV></DIV></DIV>
<DIV><BR></DIV><FONT id=role_document color=#000000 size=2 face=Arial>
<DIV>This approach could also function as a backup RX battery. No rules
against having redundant RX power. The BEC could be programmed to 'divert'
power to the flight batteries to maintain the near max voltage when
needed.</DIV>
<DIV> </DIV>
<DIV>However, I agree with Jim, I don't see the need for this. Battery
technology has/is progressing fast enough to provide us with enough power for
our sequences. I prefer the simpler approach.</DIV>
<DIV> </DIV>
<DIV>Don</DIV>
<DIV> </DIV>
<DIV>
<DIV>In a message dated 3/1/2010 4:34:31 P.M. Pacific Standard Time,
ed_alt@hotmail.com writes:</DIV>
<BLOCKQUOTE
style="BORDER-LEFT: blue 2px solid; PADDING-LEFT: 5px; MARGIN-LEFT: 5px"><FONT
style="BACKGROUND-COLOR: transparent" color=#000000 size=2 face=Arial>That's a
good idea. I imagine it would take a little modification to the <BR>rule
to specify how a system like this could be applied. This could be put
<BR>together external to the speed controller and function automatically
through <BR>active voltage sensing. Eventually the ESC mfgs could go a
step further an <BR>just integrate this right into the controller.
Slick, simple concept
Jim!<BR><BR>Ed<BR><BR>--------------------------------------------------<BR>From:
"James Oddino" <joddino@socal.rr.com><BR>Sent: Monday, March 01, 2010
7:15 PM<BR>To: "General pattern discussion"
<nsrca-discussion@lists.nsrca.org><BR>Subject: Re: [NSRCA-discussion]
Max volts<BR><BR>> I have the functional concept that solves the rules
problem. Picture a <BR>> 10S pack positive lead wired to the common
of a switch with two poles, a <BR>> piece of wire connected from one pole
to a pole on a second two pole <BR>> switch with its common connected to
the ESC. Between the other two poles <BR>> we place our 11th
cell. When the 10S pack is above 37.5 volts the 11th <BR>> cell is
bypassed and when it is below, like it will be during vertical <BR>>
maneuvers late in flight, the 11th cell is put in series to boost the <BR>>
voltage to up to 41.7 volts. At no time is the voltage over the
spec.<BR>><BR>> Having said that, I believe the 10S system provides
adequate power with <BR>> the right motor at all times of flight even if
the voltage drops to 35 <BR>> volts.<BR>><BR>>
Jim<BR>><BR>><BR>> On Mar 1, 2010, at 8:59 AM, Bob Kane
wrote:<BR>><BR>>> Going higher and regulating down would be against
the rules, the max <BR>>> volts is still limited to
42.56.<BR>>><BR>>> Bob Kane<BR>>>
getterflash@yahoo.com<BR>>><BR>>><BR>>> --- On Mon, 3/1/10,
krishlan fitzsimmons <homeremodeling2003@yahoo.com> <BR>>>
wrote:<BR>>><BR>>>> From: krishlan fitzsimmons
<homeremodeling2003@yahoo.com><BR>>>> Subject: Re:
[NSRCA-discussion] Max volts<BR>>>> To: chad@f3acanada.org, "General
pattern discussion" <BR>>>>
<nsrca-discussion@lists.nsrca.org><BR>>>> Date: Monday, March
1, 2010, 9:54 AM<BR>>>><BR>>>> Couldn't we go to a higher
voltage and<BR>>>> regulate it back down? A contstant 42.56v would be
nice!<BR>>>><BR>>>>
Chris<BR>>>><BR>>>><BR>>>><BR>>>><BR>>>><BR>>>><BR>>>><BR>>>><BR>>>><BR>>>>
From: Chad<BR>>>> Northeast
<chad@f3acanada.org><BR>>>> To:<BR>>>>
nsrca-discussion@lists.nsrca.org<BR>>>> Sent: Sun,<BR>>>>
February 28, 2010 8:48:48 PM<BR>>>> Subject: Re:<BR>>>>
[NSRCA-discussion] Max volts<BR>>>><BR>>>> You would be at
about 50% capacity at 3.85 ish volts/cell<BR>>>> (resting open
circuit), so unless you up the capacity you<BR>>>> will have a pretty
restricted flight time.<BR>>>><BR>>>>
Chad<BR>>>><BR>>>> On 10-02-28 9:25 PM, Ron Van Putte
wrote:<BR>>>>> That stirs a wild thought in my brain.
Fully<BR>>>> charged packs don't stay at 4.2 volts per cell
very<BR>>>> long. On the other hand, once the initial
charge<BR>>>> voltage is burned off by a constant load, the voltage
loss<BR>>>> curve "flattens out". What if you put
fully<BR>>>> charged 6S and a 5S packs in series and "burn
them<BR>>>> down" to 3.869 volts per cell (a total of
42.56<BR>>>> volts for an 11-cell pack) so they were legal
for<BR>>>> use. Would the voltage of this depleted 11S pack
be<BR>>>> higher than a fully charged 10S pack at the end of a
typical<BR>>>> flight? If the end-of-flight voltage might
be<BR>>>> significantly higher for the 11S pack vice a 10S pack,
it<BR>>>> would be worth investigating, even considering the
extra<BR>>>> weight of the additional cell. Come on you
electronic<BR>>>> gurus, show me where I'm
wrong.<BR>>>>><BR>>>>> Ron Van
Putte<BR>>>>><BR>>>>> On Feb 28, 2010, at 10:00 PM,
James Oddino wrote:<BR>>>>><BR>>>>>> What comes
after ...? Does it specify a load<BR>>>> or any other
conditions? Is it measured during the<BR>>>> noise test and
have a minimum value?<BR>>>>>><BR>>>>>> Just
stirring the pot, Jim
O<BR>>>>>><BR>>>>>><BR>>>>>> On
Feb 28, 2010, at 5:21 PM, John Fuqua
wrote:<BR>>>>>><BR>>>>>>> No its not
(assuming we are talking RC<BR>>>> Aerobatics). Try page RCA-2
para 4.1<BR>>>>>>> which<BR>>>> states
"Electrically-powered model aircraft are<BR>>>> limited to a
maximum<BR>>>>>>> of 42.56
volts.."<BR>>>>>>><BR>>>>>>> -----Original
Message-----<BR>>>>>>> From:
nsrca-discussion-bounces@lists.nsrca.org<BR>>>>>>>
[mailto:nsrca-discussion-bounces@lists.nsrca.org]<BR>>>> On Behalf Of
Ron Van Putte<BR>>>>>>> Sent: Sunday, February 28, 2010 7:07
PM<BR>>>>>>> To: General pattern
discussion<BR>>>>>>> Subject: Re: [NSRCA-discussion] Max
volts<BR>>>>>>><BR>>>>>>> It's in the
general rules, not in the R/C<BR>>>>
section.<BR>>>>>>><BR>>>>>>><BR>>>>>>>
On Feb 28, 2010, at 6:50 PM, Jim Quinn
wrote:<BR>>>>>>><BR>>>>>>>> Where can I
find the rule<BR>>>> for max
volts?<BR>>>>>>>><BR>>>>>>>><BR>>>>
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