Lithium or Not ?

[george kennie]

Yeah again,
That Troy always gives me the nitty-gritty details that I can't get
anywhere else!!!
You're fantastic Troy. I couldn't make it without ya. Thanks for the
full scoop!
G.

T&C Brown wrote:

> Yeah......What Troy said....  :-)T-Bone
>
>      ----- Original Message -----
>      From: Troy Newman
>      To: discussion at nsrca.org
>      Sent: Sunday, August 31, 2003 5:48 PM
>      Subject: Re: Lithium or Not ?
>       Li-ion packs. Bob, and Lance.....I have been running these
>      2000mah packs since February. They are a 2 cell pack.
>      Central sells them for $35 a pack and they have a $50
>      charger....Here is the kicker. The charger is plug in and
>      forget. It can't harm the batteries even if left on charge
>      for 3 months. Its basically a voltage regulator setup where
>      it puts out 8.4V and when the pack reaches 8.4V its
>      done....The nice thing is the charger has a Amp meter on it
>      so when the battery is empty it might take 1-1.3amps but as
>      it charges the current flow goes to zero. Once the pack is
>      charged up the current flow is zero and no juice is going to
>      the battery. You're not waiting for a light to turn color or
>      go out...You can see what is actually going into the
>      battery. Lance the pictures of the plane that burned up were
>      a guy using Lithium Metal cells. These were the first
>      Duralite batteries....The industry folks got away from
>      Li-Metal as it was highly highly dangerous when the
>      electrolyte came in contact with the air....and would
>      burn.... Let me repeat the Lithium-ion packs are not the
>      same packs as caused that guys fire. OK Here is the scoop on
>      what I use. 1 battery pack 2 cells its rated at 2000mah....I
>      can pull about 2200 out of it before it reaches the magic
>      stop voltage. The pack has a great discharge curve it is
>      almost linear until the pack is near dead. So every flight
>      might use say 0.15V per flight....It starts at 8.4V and I
>      stop flying at 7.2V on my Volt meter with a 500mah load.
>      They say you should use a 1amp load to test the voltage.
>      What I did was plot a curve of the discharge. I stuck the
>      battery on a cycler for 15min "flights" pulling the exact
>      same mah out of the pack each "flight" I then plotted it on
>      a graph vs. time. This gave a sharp knee when the pack is
>      almost of out power.....What happens is as the packs fall
>      below 7V there is not much left in them...Even though the
>      cutoff is officially like 6V or 5.5V depending on the
>      company selling you the battery...By the way many of them
>      are the same cells. And I have driven the pack down to
>      around 5V and they are still fine. I tested the batts about
>      4-5 times and got the exact same response everytime...So I
>      flew them and got the exact same response as if I was having
>      the pack sit on the cycler....I use about 180-200ma per
>      flight Setup...1 pack 2000mah, 1 Oddino regulator 5.3V...and
>      go...... the setup weights about 3.8-4oz total. I can fly
>      around 8-10 flights in a day and still have enough for more
>      flights but its getting close to time charge. Charge up is
>      about 2-3hrs on a  dead battery pack. The charger runs on a
>      12V source so you can "field" charge it just doesn't charge
>      any faster than the 2-3hrs on a dead pack...However...With
>      the AMP meter on the charger you can get an idea of the
>      charge level left in the pack. Plug it in and it draws
>      300ma...then you still about 3/4 of the battery
>      remaining....if it draws around 1amp its almost dead...and
>      needs some time on the charger...If for example its drawing
>      1amp and 1 hr later its down to about a 200mah draw on the
>      charger...pull it off and fly it some more....it will jump
>      into the curve like it already had 2-3 flights on it....and
>      act the same as it did on flights 4-5-6 from a full
>      charge....There is no memory, no need to drain the pack
>      before charging....you can charge after one flight or after
>      10 flights..... Also if you charge and don't fly for like a
>      month...the battery is still sitting at about 98% full
>      charge....I have a pack I charged before the Team
>      Trials....just measured it and full its 8.4V and it reads
>      today 8.31V...It was charged last in Mid JUNE! Like the 10th
>      of June...and its still got 8-9 flights in it.... These
>      packs are awesome. They are dummy proof and allow me to fly
>      all day long...now your mileage may vary depending on your
>      battery drain....But I'm running a YS DZ on a Hyde Mount
>      with 5 digitals even a little 3421 on the
>      throttle.....9411SA's on the Ailerons and 8411SA's on rudder
>      and Elevator...So I'm working the packs pretty hard...  Just
>      ask ole' man Whitachre...Bob would come out this spring and
>      what me fly all day on two models...I would drain 2 gallons
>      of fuel just flying back to back to back...about 16-18
>      flights in a day....and never charge...just fuel, test, and
>      fly. Since being in GA I have been out much less than before
>      the NATS and I have gone flying 2-3 days on the same charge.
>      Maybe 3-4 flights per day. I love the way they
>      work.....Can't speak for the Duralite, Powerflite, and
>      others...but the Central Hobby packs are great....I gave all
>      my Nicd packs away to guys that will use them. I don know
>      the Powerflite and the NMP (centrals) are the same cells. As
>      are the Superbatterypacks.com, and some of the other
>      suppliers...Now Duralite and Powerflite have special
>      chargers that are expensive but they can charge 2-3-4-5
>      packs at a time....this charger only does one pack at a
>      time....buts a dummy proof charger...reverse polarity it
>      doesn't do anything...lites a red LED to tell its
>      backwards....Green LED says Polarity is good and plu it
>      in....If the amp meter says zero its charged....If it reads
>      1.3amps the pack was dead....pretty simple...and you can use
>      the charger like a fuel meter....the closer the meter is to
>      zero the more charge is inside the battery pack.... As for
>      the age issue. My packs are pretty new...but I know people
>      that have packs going on 2 years old now. The age failure
>      seems to be a slow loss in capacity...as the pack gets
>      old...they simply don't reach 8.4V any longer...Instead they
>      it 8.2 then 7.9V and then slowly creep down to 7.5V....At
>      this time is when you know to get a new one. I have 2 packs
>      I have flown since Feb....that's going on 28 cases yes cases
>      of fuel this year.....I'm approaching 1000 flights just this
>      year flying two different models...I think the technology is
>      pretty sound and works well. I was leery before as I had
>      some bad luck with the old style li-METAL packs Duralite
>      originally sold....These packs are much more forgiving and
>      easier to manage. I would recommend them over ni-cds or
>      Nimh....weight is not so much the issue its the consistent
>      discharge curve....they are AWESOME.....And not priced too
>      much out of range.....$35 a pack....this is slightly higher
>      than a 2000mah Nicd pack... Troy
>
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