<DIV> Thanks Troy as always your reply is great. I have an engineer friend that works for Motorola in the celular phone division. He works with battery technology all day. For what it's worth he really dislikes Li ions and totally favors the new poly's. He says that the Ions have a charge life of only 400 cycles and that polys will go 2000. I'm not an expert on this but I find his opinion important to consider. Now as far as cost batteriesamerica in Wisconson sells the poly packs for the following:</DIV>
<DIV><A href="http://www.batteriesamerica.com/lithium_polymer.htm">http://www.batteriesamerica.com/lithium_polymer.htm</A></DIV>
<DIV>7.4 1900 pack at 2.6oz. is 34.95</DIV>
<DIV>7.4 2200 pack at 3.17oz is 38.55</DIV>
<DIV> I appreciate the opinions and since I rely on them I asked for the group to respond to see if I was missing something.Troy, what regulator fdo you use?</DIV>
<DIV> Thanks again, Mike Mueller <BR><BR><B><I>Troy Newman <troy_newman@msn.com></I></B> wrote:</DIV>
<BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">2C is a huge load and there is no way that your plane as a RX pack should<BR>ever see that kind of load.<BR><BR>the Li-ion pack are 2000mah....and you are talking of a 4amp or 4000mah<BR>load....now maybe on an electric plane with a BEC and all digitals....yes<BR>the load will be up past this....<BR><BR>A reference. YS 140DZ n a Hyde ARA mount, All the best digitals you can<BR>use. High Speed, super tight deadband stuff. 9411's...8411s...8417s and even<BR>a digital mini on throttle 3421s<BR><BR>I'm drawing 170-200ma per flight...flights are about 10-13mins. So take<BR>this too its worst and say 200ma per flight that is 1/10thC or 0.1C...this<BR>F3A stuff with the snaps and stuff that come with it.<BR><BR>What I have found is for the size pack we are dealing with for RX operation<BR>the weight savings are minimal for Li-ion to Poly to change....a 2000mah<BR>Li-ion pack is 3.4oz...a
1900mah 2 cell Li-Poly weighs in at 2.8oz....On my<BR>scale... S0 you are saving about 1/2oz total....but you are gaining about<BR>$15 in price tag too. $35 for the Li-ion and $50 for the Poly.....40%<BR>increase in costs to get a high draw battery when you are not even the<BR>current Ion cells to their max draw capability.<BR><BR><BR>Don't get me wrong I think the poly's are a great pack and they will only<BR>get better......I just don't think at this point in time you should run<BR>anything less than 1900 or 2000mah for a RX pack because weight is not an<BR>issue at this size level....So you go to a 1300mah pack and cut your flying<BR>almost in 1/2..to save 1oz...and the differences in Ion-vs Poly at this<BR>level are very very minor in terms of physicals.<BR><BR>The question comes down to are the Li-ions dead technology because the Poly<BR>has some minor weight savings at this small level and we should just start<BR>switching over to Poly's all the way...I don't know. I would not
say they<BR>are "any wiser or any worser" (Ali Quote) in terms of application of the<BR>battery.<BR><BR>Now in the Electric powered model the Poly has the huge advantage of the 6C<BR>power draw.....Especially in an E Pattern model....42Volts pulling<BR>50-60-80amps then I can certainly see for sure that the poly is the pack of<BR>choice. That extra 1/4-1/2 oz per cell adds up when you are talking 11 cell<BR>packs and also 8000mah.<BR><BR><BR>I'm not so sure the Ions don't still have a place in our systems...I have<BR>been using them now over a year..with lots and lots of flights on a couple<BR>Li-ion packs. In my opinion they are the best battery setups I have ever<BR>run. The NMP packs and Charger from Central are 100% dummy proof. We have<BR>tried to mess them up and to no avail.....You plug them up and everything is<BR>setup and done...no nothing special required. Can't overcharge the cells<BR>this is where the safety stuff comes in.....and they are better than Nicds<BR>as for
safe and easy operation. The discharge curves are superb and very<BR>linear...not the peak and false peak stuff Nicds and Nimh's go<BR>through.....Its simple....its like a fuel tank....Plug the tank in and<BR>re-fuel the battery....As it drains down the tank tells you where it is<BR>exactly......its just your fuel gauge on your car.<BR><BR><BR>Simple and easy.<BR><BR><BR>Troy Newman<BR><BR><BR>----- Original Message ----- <BR>From: <FISHGOD@POBOX.MTAONLINE.NET><BR>To: <DISCUSSION@NSRCA.ORG><BR>Sent: Monday, January 26, 2004 9:40 AM<BR>Subject: Li poly's vs: Li Ions<BR><BR><BR>With my experience with Li-poly and Li-Ion I would have to assume that the<BR>high current Li-poly's would be a better choice. The standard Li-ions<BR>cells are only good to 2c and that is putting a pretty healthy load on<BR>them. While the new high current Li-poly's are rated at 6C for 80% of the<BR>capcity. With the demands of digital servos I would think that the poly's<BR>would be a better choice. Of course
I am no battery expert this is just<BR>from my experience with small electric planes.<BR><BR>Michael Laggis<BR>NSRCA 3618<BR><BR><BR><BR><BR><BR><BR>Li-poly's work. They seem to work as well as Li-ons. They are being sold<BR>as RX packs as well as electric motor packs.<BR><BR>That being said, I have noticed that my Li-poly's drop off a little after<BR>being fully charged, I have not yet tested how long they hold their charge<BR>before they are used.<BR><BR>In the final analysis, if they work well, then they are lighter and thus<BR>attractive to pattern players.<BR><BR>Regards,<BR><BR>Eric.<BR><BR><BR>-----Original Message-----<BR>From: discussion-request@nsrca.org [mailto:discussion-request@nsrca.org]On<BR>Behalf Of mike mueller<BR>Sent: Monday, January 26, 2004 8:52 AM<BR>To: discussion@nsrca.org<BR>Subject: Li poly's vs: Li Ions<BR><BR><BR>Last year I ran a 2 cell 7.4 2000 mil. Li Ion pack in my plane. Since<BR>then I've been building small E. planes and have gotten used to the
newer<BR>technology of Li poly's. My question to all you experts is should all my<BR>new receiver battery packs from here on be Li Poly's? Does anyone see an<BR>advantage or disadvantage to this. The setup I thought would be best was a<BR>7.4v 2100 Mil 2S Thunder Power Li Poly with the appropriate 5.3 regulator<BR>( what's your suggestion?) for 5 JR digital servos and a Jr pcm receiver.<BR>If this has been asked before I apologize I just havn't seen it discussed.<BR>Also I have a Triton charger so that's not an issue. Thanks, Mike<BR><BR><BR>----------------------------------------------------------------------------<BR>----<BR>Do you Yahoo!?<BR>New Yahoo! Photos - easier uploading and sharing<BR><BR>--------------------------------------------------------------------<BR>mail2web - Check your email from the web at<BR>http://mail2web.com/ .<BR><BR><BR>============# To be removed from this list, send a message to<BR># discussion-request@nsrca.org<BR># and put leave discussion on the
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