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<DIV><FONT face=Arial size=2>FWIW - I've been using a Sears Marine part #27582
lead acid battery as a power source at the field. Weight is about 65
pounds. Rated capacity is 108 amps (can't remember what discharge rate was
used to yield that capacity).</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>At 75F, the average voltage of the lead acid
battery when charging a pair of TP 5s4p5300s at 5.5 amps w/ Schulze 330s is
about 11.5v (~220 watts load, ~20 amps draw on the lead acid battery).
Charging 4 sets (1 at a time) at an average of 4000 mah each, uses about 40% of
the lead acid capacity (according to the Schumacher lead acid charger).
Running 4 chargers staggered (so peak amps are not overlapping) seems
fine. Running 4 chargers at ~450 watts pretty much crushes the voltage of
the lead acid unless it is right off the charger.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>And, 2 sets of lipos and 4 chargers (or 2 BIG
chargers) is sufficient for flying on the weekend, when there is a rotation of 3
or more pattern guys taking turns. So 2 sets of lipos, 2 big chargers, and
1 big lead acid battery will easily get 6-8 flights for a day at the
field.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Regards,</FONT></DIV><FONT face=Arial size=2>
<DIV><BR>Dave Lockhart</DIV>
<DIV><A href="mailto:DaveL322@comcast.net">DaveL322@comcast.net</A></DIV>
<DIV></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=wgalligan@goodsonacura.com
href="mailto:wgalligan@goodsonacura.com">Wayne Galligan</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> Monday, April 17, 2006 10:50
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion]
Electrics</DIV>
<DIV><BR></DIV>
<DIV><FONT face=Arial size=2>Bob,</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>All good points. We see many battery
failures in the car business due some or all of what Bob stated.
Sulfating being the main culprit caused from low charge and overheating
conditions. Also the "NO Maintained" batteries will also get low on
water causing failure of the battery. If you find your battery low on
fluid add only DISTILLED water. Lead acid or gell cell batteries
work best when kept at near or full charge. </FONT></DIV>
<DIV><FONT face=Arial size=2>I am adding a battery to my trailer and I am gong
to use a solar powered device to keep it at full charge status. See this
link. <A
href="http://oil-tech.com/catalog/index.php?cPath=1_27_28&osCsid=942e0092cd33b4ed5abc90e57ca8eca7">http://oil-tech.com/catalog/index.php?cPath=1_27_28&osCsid=942e0092cd33b4ed5abc90e57ca8eca7</A>
It is called the SOLARGIZER.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>Wayne Galligan</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2></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> Monday, April 17, 2006 6:19
AM</DIV>
<DIV style="FONT: 10pt arial"><B>Subject:</B> Re: [NSRCA-discussion]
Electrics</DIV>
<DIV><BR></DIV>
<DIV>Nat,</DIV>
<DIV> </DIV>
<DIV>I've learned a lot about the care and feeding of lead-acid batteries
the last couple of years, from having to replace one in my camper a couple
of years ago.</DIV>
<DIV> </DIV>
<DIV>First, don't discharge 100%. For the longest life, try not to discharge
below 50% capacity. That means get a bigger battery, or more of them.</DIV>
<DIV> </DIV>
<DIV>A "marine" battery is not a true deep cycle battery. It is usually a
compromise between a standard starting battery and a true deep-cycle
battery. For best deep-cycle performance, get a pair of 6v golf-cart
batteries. They are usually a little taller, have much thicker solid plates,
and can be discharged many more times than marine batteries.</DIV>
<DIV> </DIV>
<DIV>Don't even try to use a conventional starting battery for deep-cycle
applications. If you really want to use the battery in your car to charge
from, install a deep-cycle battery, but go up about 25% or more in size.
Deep cycle batteries can be used for starting, but for the same size they
don't have as much cold-cranking amps, hence the larger size required.
Conventional starting batteries have porous plates, the additional surface
area helps to increase the cranking amps, but deep-cycle use will cause
sulfation that clogs up the pores and quickly reduces the cranking
amps.</DIV>
<DIV> </DIV>
<DIV>Sealed or gell cells are not good for deep cycle use, or so I have been
told. They typically are used for standby power sources, due to their low
maintainance. They can't be charged as quickly since pressure builds up and
can't be vented.</DIV>
<DIV> </DIV>
<DIV>AGM (absorbed glass mat) batteries are good, but cost 2-3 times as much
as similar sized vented wet cell batteries.</DIV>
<DIV> </DIV>
<DIV>The only way to truly determine the charge state of a lead acid battery
is to measure the specific gravity using a hygrometer (sp). You can measure
the *resting* voltage to determine the charge state, but the battery must
remain disconnected from any load/charger for some time for this to be
anywhere near accurate. Basically, 12v or less is discharged, 12.7 is fully
charged.</DIV>
<DIV> </DIV>
<DIV>Always store a battery fully charged. When a lead-acid battery is
discharged, sulfation will occur. Immediately charging the battery is
supposed to help get rid of the sulfation, but the longer you wait, the
harder it is for the sulfation to be reversed.</DIV>
<DIV> </DIV>
<DIV>The best chargers are ones that have 3 or 4 stages. You can start with
a charge voltage of 14.4 volts, but after some time the voltage should be
reduced to 13.6, and for float charge it should be reduced to 13.2, which
can be left connected indefinitely. Some chargers have a cycle that sets the
voltage to 14.4v for several minutes every few hours, which helps to stir
the electrolyte (not needed in AGM batteries).</DIV>
<DIV> </DIV>
<DIV>You can charge to 80% capacity in about 4 hours with a good battery and
charger. The last 10% of charge can take 24 hours or more.</DIV>
<DIV> </DIV>
<DIV>Some of the best chargers are actually converters made for RV use, and
they also double as 12v power supplies. Iota and Progressive Dynamics are
two good, popular brands. I installed a <A
href="http://www.toprudder.com/rv/pd9145.html">PD9145</A> in my RV.</DIV>
<DIV> </DIV>
<DIV>I hope this helps.</DIV>
<DIV> </DIV>
<DIV>Bob R.</DIV>
<DIV> </DIV>
<DIV> </DIV>
<DIV><BR><BR><B><I>Nat Penton <natpenton@centurytel.net></I></B>
wrote:</DIV>
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<DIV><FONT face=Arial size=2>The only battery giving me a problem is the
lead acid Marine 'deep discharge' battery used for field
charging of the lipos. It has lost about 70% of it's capacity in
seven months.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>It provided six 12min flts when new and was
purchased from Academy Surplus for $40. It has provided a total of
maybe 80 flights ( 30 cycles ??? ). The problem is likely due to my
maintenance ( lack thereof ). I left the battery in a partial
discharge state sometmes for weeks. </FONT><FONT face=Arial size=2>You can
find maintenance needs on Google at agmbatteries, courtesy Earl
Haury.</FONT></DIV>
<DIV><FONT face=Arial size=2></FONT> </DIV>
<DIV><FONT face=Arial size=2>West Mountain sells a gell cell, 54#, 84ah,
rated for 500 cycles @ 100% discharge ( 20hr discharge rate ), $149 del. I
will see how it performs under our conditions.</FONT></DIV>
<DIV><FONT face=Arial
size=2>
Nat</FONT></DIV>No virus found in this outgoing message.<BR>Checked by AVG
Free Edition.<BR>Version: 7.1.385 / Virus Database: 268.4.1/310 - Release
Date:
4/12/2006<BR>_______________________________________________<BR>NSRCA-discussion
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