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<DIV><FONT color=#0000ff face=Arial size=2><SPAN
class=980330506-27022006>Ed,</SPAN></FONT></DIV>
<DIV><FONT color=#0000ff face=Arial size=2><SPAN class=980330506-27022006>"C"
stands for "Capacity". Therefore a C/10 charge rate for a 2200 mAh pack is
indeed 220 mA (1 10th the capacity). Sounds simple so far, now for the confusing
part. If you take these numbers literally, you would think that at C/10 you
should charge for 10 hours and at C/1 you should charge for 1 hour. C/2 means
charge for 2 hours. Not really. In reality a C/10 charge rate usually takes 16
hours to fully charge a discharged battery. Maybe that's where the confusion
comes in. Luckily you really only need to use a few different charge rates: C/10
for 16 hours is a slow / overnight charge. 2C or 4C is good for fast charging
NiMH's and NiCds respectevly. NiMH's don't like to be charged quite as fast as
NiCds so I usually charge them at 2C for a little over half an hour after
they're conditioned at the C/10 rate. A good NiCd pack will accept 4C for about
15 minutes although smaller batteries (<500mAh) aren't really too happy with
this. To condition ne batteries, I charge at C/10, then discharge at 500mA
(not critical but you should do it at a rate that is safe for the
battery). I repeat this process at least 3 times on a new pack. I use an
Alpha 4 so it gives me the battery capacity after discharging. You will see the
capacity go up as you cycle a new pack. A good one should reach 90%
capacity (or more) after a few cycles - if it does, it's ready to use. Hope this
answers your question.</SPAN></FONT></DIV>
<DIV><FONT color=#0000ff face=Arial size=2><SPAN class=980330506-27022006>
<P><FONT size=2>John Pavlick<BR><A href="http://www.idseng.com/"
target=_blank>http://www.idseng.com</A><BR> </FONT>
</P></SPAN></FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=Tahoma><FONT size=2><SPAN
class=980330506-27022006> </SPAN>-----Original Message-----<BR><B>From:</B>
nsrca-discussion-bounces@lists.nsrca.org
[mailto:nsrca-discussion-bounces@lists.nsrca.org]<B>On Behalf Of </B>Ed
Deaver<BR><B>Sent:</B> Monday, February 27, 2006 12:57 AM<BR><B>To:</B> NSRCA
Mailing List<BR><B>Subject:</B> Re: [NSRCA-discussion] NiMH follow
up<BR><BR></DIV></FONT>
<BLOCKQUOTE
style="BORDER-LEFT: #0000ff 2px solid; MARGIN-LEFT: 5px; PADDING-LEFT: 5px"></FONT>
<DIV>OK, for us non-electical whiz bang guys, please explain the C
charge. I have heard it before and tried what was suggested on RCU
without success.</DIV>
<DIV> </DIV>
<DIV>My new NmHD pack is a 2200mah, 4 cell pack. To condiditon it
properly for first flights what should I do? </DIV>
<DIV> </DIV>
<DIV>Does 1/10 C mean charge at 220 mah for 16 hrs??</DIV>
<DIV> </DIV>
<DIV>THanx for the explanation.</DIV>
<DIV> </DIV>
<DIV>ed<BR><BR><B><I>Michael Cohen <precisionaero@comcast.net></I></B>
wrote:</DIV>
<BLOCKQUOTE class=replbq
style="BORDER-LEFT: #1010ff 2px solid; MARGIN-LEFT: 5px; PADDING-LEFT: 5px">Thanks
to those who helped me with the advice. The 1/10 C change was the
<BR>answer. Both packs are happily at 1610-1690 capacity for their 1650
rating. <BR>I also visited an old friend's website, Electrodynamics in
Michigan. They <BR>had an interesting write up on their website about NiCD
(with a little NiMH <BR>sprinkled in! ). I used to buy all my switches,
extensions, and battery packs <BR>from them when I lived in the Great White
North. Their advice was 1/10 C <BR>also, but they had lots of other good
info there as well. I recommend you <BR>take a look, unless your one of
those Lithium people.<BR><BR>Mike Cohen
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