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Old 11-04-2005, 08:34 AM   #31
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I think one thing people are also forgetting is NiMh can swell and explode as well, infact much easier just by have the battery shift and short on your chassis. I have actually seen a guy pull of the track with a smoking car and as he went to pick it up the car exploded, even ripping part of the body shell and he was running NiMh. With these batteries it looks like the only abuse you can give them is in the charging stage since they claim there is no need to discharge or cycle. All batteries are dangerous just in different ways as long as you are careful anything can be used safely.

Next year I am going nuclear LOL!
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Old 11-04-2005, 09:09 AM   #32
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Originally Posted by AdrianM
your new Lexus
Ha, Lexus? Your funny
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Old 11-04-2005, 11:39 AM   #33
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Guys goto www.radioracers.co.uk and check out lipo in the video section might make you think a bit...
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Old 11-04-2005, 11:53 AM   #34
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I would but the link to "videos" is dead maybe you could just tell us what we are suppsed to be seeing?
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Old 11-04-2005, 12:04 PM   #35
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Hmmm.... it worked for me. Anyway, they overcharged a Li-Po. It swelled up like a balloon and exploded into a fireball.
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Old 11-04-2005, 12:06 PM   #36
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Hopefully there will be rules changes to accommadate these cells. Like longer races, lower minimium weight (lipo's weigh 150grams less per pack), lower ride heights, ect.......
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Old 11-04-2005, 12:28 PM   #37
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I saw on Tower that the Car Lipo are already available...
forget Orions 4800mah pack..just go straight for the 6400's.

Kokam FMA Direct Scorpion 3200mAh 7.4V Lithium Polymer Battery
2s Super High Discharge Lithium Polymer battery Pack
supplies 7.4V at high continuous current
http://www2.towerhobbies.com/cgi-bin...?&I=LXKLK7&P=7


Kokam FMA Direct Scorpion 6400mAh 7.4V Lithium Polymer Battery
2s Super High Discharge Lithium Polymer battery Pack
supplies 7.4V at high continuous current
http://www2.towerhobbies.com/cgi-bin...?&I=LXKLK8&P=7
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Old 11-04-2005, 12:31 PM   #38
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Quote:
Originally Posted by i.a.s
Guys goto www.radioracers.co.uk and check out LiPo in the video section might make you think a bit...
Yup, if you grossly overcharge, charge at too high a rate or short out the pack you will have a front row seat at a re-enactment of the video. If you run LiPo you have to educate yourself on their proper use.

That said the Orion LiPo pack is made from the latest generation cells and they have overcome a lot of the safety issues of the early LiPo packs.
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Old 11-04-2005, 12:32 PM   #39
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Quote:
Originally Posted by rc-zombies
I saw on Tower that the Car Lipo are already available...
forget Orions 4800mah pack..just go straight for the 6400's.

Kokam FMA Direct Scorpion 3200mAh 7.4V Lithium Polymer Battery
2s Super High Discharge Lithium Polymer battery Pack
supplies 7.4V at high continuous current
http://www2.towerhobbies.com/cgi-bin...?&I=LXKLK7&P=7


Kokam FMA Direct Scorpion 6400mAh 7.4V Lithium Polymer Battery
2s Super High Discharge Lithium Polymer battery Pack
supplies 7.4V at high continuous current
http://www2.towerhobbies.com/cgi-bin...?&I=LXKLK8&P=7
I already have some of the scorpion 3200 packs, u have to have the FMA charger to charge them. However charging with the FMA charger can be done in 20 mins. This gets the pack to 90% capacity. And due to the flat discharge curve of lipo packs it doesnt need to be topped off to 100%. I really love mine, more punch NiMh. I hope that some of the other orion versions can be balanced and charged with the FMA charger in 20 mins.
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Old 11-04-2005, 12:46 PM   #40
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I memory serves me correct if you continue to over charge a NiCd or NiMh wackyness insuse as well. Not to mention the fun when one shorts out on your chassis.
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Old 11-04-2005, 01:00 PM   #41
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some info i found

Lithium polymer batteries are rechargeable batteries which have technologically evolved from lithium ion batteries. The lithium salt electrolyte is not held in an organic solvent, like in the proven lithium ion design, but in a solid polymer composite such as polyacrylonitrile.
There are many advantages of this design over the classic lithium ion design. Because of the solid polymer electrolyte there is no need for the organic flammable solvent. Thus these batteries are less hazardous if mistreated. Furthermore, since no metal battery cell casing is needed, the battery can be lighter and it can be specifically shaped to fit the device it will power. Because of the denser packaging without the holes between cylindrical cells and the lack of metal casing, the energy density of Li polymer batteries is over 20% higher than that of a classical Li ion battery.

The Lithium Polymer still has some serious problems with internal resistance and has a limited life cycle.

The only advantage to it compared to a standard Li-Ion is that manufacturers can change the shape of it. Outside of that, there is no particularly good reason to switch to polymer if you have a standard Li-Ion battery.

The currently commercialized ones are two technologies (both actually Li-ion-polymer) where "polymer" stands for "polymer electrolyte/separator". Let's call them "polymer electrolyte batteries"

The idea is to use an ionically conducting polymer instead of the traditional combination of a microporous separator and a liquid electrolyte. This promises not only better safety as polymer electrolyte does not burn as easily, but also the possibility to make battery cells very thin as they don't require pressure applied to "sandwich" cathode+anode together. Polymer electrolyte seals both electrodes together like a glue.

Design is: anode (Li or carbon-Li intercalation compound)/conducting polymer electrolyte-separator/cathode (LiCoO2 or LiMn2O4)

Typical reaction:

anode: carbon-Li(x) - xLi+ - xe
separator: Li+ conduction
cathode: Li(1-x)CoO2 + xLi+ + xe

Polymer electrolyte/separator can be real solid polymer (polyethyleneoxide, PEO)+LiPF6 or other conducting salt +SiO2 or other filler for better mechanical properties (such systems are not available commercially yet). Some are planing to use metallic Li as anode, whereas others want to go with proven safe carbon intercalation anode.
Both currently commercialized technologies are using PVdF (polymer) gelled with conventional solvent+salt, like EC/DMC/DEC etc. Difference between two technologies is that one (Belcore technology) is using LiMn2O4 as cathode, and other more conventional LiCoO2.

Other more exotic not yet commercially available Li-polymer batteries actually are using polymer cathode, so we could call them "real polymer batteries". For example Moltec is promising to deliver battery with plastic conducting carbon-sulfur cathode. They seem to have problems with self-discharge and other stuff as well as manufacturing cost I guess.

Yet another proposal is to use organic sulfur containing compounds as cathode in combination with electrically conducting polymer (polyaniline for example). This promises high power capability (e.g. low internal resistance) and high discharge capacity, but have problems with cycleability and first of all - production cost.


This article is from Wikipedia. All text is available under the terms of the GNU Free Documentation License.
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Old 11-04-2005, 01:17 PM   #42
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I had read that info on the ezonemag.com (rcgroups.com) message board over a year ago. Several LiPo importers chimed in and said that this was very old information. LiPo development is moving extremely quickly. Due to consumer applications of LiPo batts lots of $$ have been put into their development.

The LiPo packs I am using today to fly my r/c planes are worlds better than the stuff I bought a year ago.
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Old 11-04-2005, 01:31 PM   #43
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Quote:
Originally Posted by AdrianM
I had read that info on the ezonemag.com (rcgroups.com) message board over a year ago. Several LiPo importers chimed in and said that this was very old information. LiPo development is moving extremely quickly. Due to consumer applications of LiPo batts lots of $$ have been put into their development.

The LiPo packs I am using today to fly my r/c planes are worlds better than the stuff I bought a year ago.
so these new batteries that are coming in do have lo internal resistance and can handle the current draw from our motors
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Old 11-04-2005, 01:37 PM   #44
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Your CG just dropped 3/8". Your power-to-weight ratio has increased drastically. This will separate the driver ranks well.

car design can progress now, but will people be able to drive it?
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Old 11-04-2005, 01:39 PM   #45
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Post Wow more interest than I thought it would get.....

if they made a 4 cell version perhaps 30 min races in 1/12th wouldn't be out of the question. I can make 15-16 min now with my 19T.

Speaking of questions I've got one at the bottom of the 1/12th thread at the moment

http://rctech.net/forum/showthread.p...67#post1914367

if someone could take a quick look it would be appreciated.

Right back to the topic.
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