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Old 10-01-2004, 12:46 PM   #1
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Default Lithium Polymer - Are Any of the Current NIMH Matchers Experimenting with Lipoly??

Just wondering if any of the current major battery matchers like Promatch and Fukuyama are experimenting or thinking about testing Lipoly cells?
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Old 10-01-2004, 03:14 PM   #2
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I wish Sanyo/Panasonic/GP would experiment Lipoly Sub-C cells so they would be legal for racing
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Old 10-01-2004, 03:25 PM   #3
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i believe lipos are to dangerous at the moment to even consider using in a racing enviroment...but maybe they should consider testing li-ions (i think they are called that) as they seem to be much safer but don't loose as much voltage or what ever.
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Old 10-01-2004, 03:38 PM   #4
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Quote:
Originally posted by raving-monkey
i believe lipos are to dangerous at the moment to even consider using in a racing enviroment...but maybe they should consider testing li-ions (i think they are called that) as they seem to be much safer but don't loose as much voltage or what ever.
Yes they should make some more user friendly Lipos...perhaps with an internal safety system...don't think they would come soon

Are Li-ions used for RC application??
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Old 10-01-2004, 03:57 PM   #5
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yeah, they are used in planes and helis..aswell as lipos but not everyone likes a lipo blowing up in their lovely new heli do they

i don't think li-ions carry as much capacity..or voltage but they are still pretty good...and cheaper i think.
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Old 10-01-2004, 05:02 PM   #6
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Actually a Liploy of comparable weight to a pack of 3300's has a capacity of 8200 mAh and a max continuous discharge of 40A.

You can see the stats here

http://www.thunderpower-batteries.co...batteries.html
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Old 10-01-2004, 05:25 PM   #7
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Recently, it seems that lipolys have been becoming safer. On www.radiocontrolzone.com, there are quite a few people using them, the main person being "craps".

One turnoff is the charging time; although they may make the races longer, it will also make the time to charge it twice as long also. This in turn would cause us to have at least a minimum of an hour in between each qualifier.
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Old 10-01-2004, 05:55 PM   #8
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Quote:
Originally posted by rcguy2477
Recently, it seems that lipolys have been becoming safer. On www.radiocontrolzone.com, there are quite a few people using them, the main person being "craps".

One turnoff is the charging time; although they may make the races longer, it will also make the time to charge it twice as long also. This in turn would cause us to have at least a minimum of an hour in between each qualifier.
If those batteries become legal one day they will be probably much cheaper...so you can have a few charged before the race.
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Old 10-01-2004, 05:57 PM   #9
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yeah the charging time is a drawback...it takes me 60 min to fully charge my 8000 mah pack. So what I do is charge it the night before. Then on race day, I use that pack for all my practice runs. Then I save my 3300 NIMH for the actual race.

Also, if you use the correct charger, there is no more danger from a LiPoly compared to a NIMH.
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Old 10-01-2004, 08:00 PM   #10
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Right now the biggest problem with using lipo in cars would be from crashes. Any hard crash can cause an internal short and susequent fire. Just think you get hit hard in the first corner at the start and them three corners later your car burst into flames!!!
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Old 10-01-2004, 08:04 PM   #11
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One of the things I've heard is that the cells don't need to be matched. So I wouldn't see why a matcher would experiment, but I could be mistaken.

Also they have more capacity and more voltage and less weight. It all depends on the wire method of how many "packs" are in series or parallel.

The more in Parallel the higher the rating, the more in series the higher the voltage.
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Old 10-01-2004, 08:11 PM   #12
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Default Lithium Polys are safer than the old Li/Ions

The polymer is supposed to make them handle higher charge rates without overtemping and contain gasses better if they are overcharged....ie, slower release of gas as opposed to outright explosion.

They are very popular with the Mini RC crowd...being used to power 1/18th scale MiniT trucks to 40-50mph resulting in spectacular crashes. I've not heard of one exploding yet. I think the technology has come a long way.

Charge rates for the little packs run in the 1 to 2 amp range (about 1/3rd as fast as NiCds) with discharge rates way up in the 10 to 15amp range. This is for the tiny little 3 cell 11.1V 1,100mAh packs. Larger packs can handle 3-4 times that much current.

My Xray M18 which runs a 5,400Kv Mamba brushless with a Li/Poly pack will motivate around 45mph, geared for acceleration...not top speed.

Packs run in series and parallel. Parallel for more energy storage. Series for more voltage. 3.7 volts per cell. A typical 11.1V 3 cell (often designated as a 3S for 3 in series) Li/Poly pack is much lighter and smaller than a 8 cell 9.2V NiMh pack.

Last edited by Disaster; 10-01-2004 at 08:17 PM.
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Old 10-02-2004, 09:44 AM   #13
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I think there's a lot of misconception about LiPo's floating around this site. They are not as sensitive as you think they are. Personally, I have not "Flamed up" my LiPo's and I have hit the ground going about 30 or 40 mph with my flying wing. Just the other day I directly bounced the plane off the floor with the battery compartment hitting first at about 20 mph since I failed to pull up out of a windy stall.

LiPo's are awesome. They are light. Use the right charger and it'll be fine!!! I'm loving mine right now.

Are you afraid of the Li-batts in your pocket day-in, day-out? In your cell phone? Someone said that to me, and I never realized it either.
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Old 10-02-2004, 09:52 AM   #14
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Default Exactly...dropped my cell phone in ocean

It did not explode. They are everywhere...phones, pdas, laptops. It is definitely time the RC community accepts them.
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Old 10-02-2004, 01:11 PM   #15
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Quote:
Originally posted by donoman
Are you afraid of the Li-batts in your pocket day-in, day-out? In your cell phone? Someone said that to me, and I never realized it either.
So does this mean I should take my cell phone out of my pocket?
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