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<DIV><FONT face=Arial size=2>Bob</FONT></DIV>
<DIV><FONT face=Arial size=2>Appreciate the input regarding lead acid
batteries. West Mountain may not be best choice as a place to buy a
battery, price wise, but they do furnish info I did not find otherwise.
T</FONT><FONT face=Arial size=2>hey only sell one size gellcell and an
equivalent size agm. Check the info they furnish regarding number of cycles vs
life of battery.
Nat</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 8:19
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:
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