Why lipos shouldn't be used in larger airframes - Page 3 - RC Groups
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Mar 26, 2006, 07:02 PM
UN Earth peoples true enemy
treehog's Avatar

vidio cant be saved????


the majority in this world suffer from slow band issues
eg 1/2 meg or 1 meg downloads with high contensions

watched some of vidio

with a mac you cant save from that site the vidio

proabably the same with pc windows x

vidio gallery or similar is better for saving film

you can click and save and watch later when its all downloaded
if you dont want people to save film wont stop those with deeper pockets than mine with special programs to save

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Mar 26, 2006, 09:23 PM
Registered User
I have so far come across 2 accidents (incident more suit?) with related to use of Lipo.
One happened 2 years ago when I just moved in the new house, everything just had found the temp place to settle down and I was so anxious about new environment. As a result I left my lipo charging while went out for dinner.
Then the phone rang , fire broken out and put off though. Whole new room was burnt down......luckily my cats inside are safe.
Second happened about 3 weeks ago,when a 3s1p pack finished charging, and I thus 'shove/ push' it back to a Nobody, I then smelled sth which is so stinky, my reflex told me to took out 'everything'..one cell began to swelled and heat up so quick I then throw it onto the floor of bathroom and closed the door, that is the way I did for several times in similar cases. But this time is not lucky enough......huge fire broke out and I let it over since I know nothing would be hurt except heavy smoke generated....as my predict, that was 6AM ,....the ventilator extract smokes...also lucky too for such failure not happened when airborne.

2nd lesson learnt beside don't leave home with charging unsupervised, that is the squeeze of lipo packs may easily short the cells and ......
Note that I have already opened the pack and wrap some wires with Kapton and filled the top of PCB with hot glue, which is still not satisfied so later bought packs are filled with sort of 'greyish' epoxy which has higher boiling pts and harder in nature.

On the other hand, I will not say that Lipo is absolutely dangerous for its chemistry has highly spontaneous characterisitic, because when I crashed my Zoom at full speed hit the ground sec aft launch, 2 packs of 3s1p (same branded and size as in 2nd case)just smoked, but when I kicked the wires off....no 'explosion' or more vigourous reaction. ..and before l left, I picked up some BIG stone to crush it, it didn't explode or entertain me either.

So, if just response to the title by each word meaning, I would disagree: because if the plane is so roomish, then some safety issues could be relieved, eg, NO need to squeeze it, and bigger plane could be opened more vent area to help the cooling without affect the structure of plane.
And I really like the use of Lipo in most of sport planes for their higher cap and lighter weights.

But I would not think Lipo could/ should be use in HIGH DISCHARGE RATE no matter how the high the NOMINAL DIS RATE is claimed or touted in ads, because lipo are not designed for that purpose in the very beginning. Unless there is someone who re-invent a ENTIRELY NEW Lipo which has proper ventilation valves as used in the +ve terminal of secondary batts.(rechargable cells). Even the potential dangers of fire/explosions could be get away with high temp genrerated in high amp usage, and the joints between the wimpy tap terminals will/may easily be damaged or detached from the internal contents of lipo. All of the 1st generation of KK lipos were killed in that manner.
So I would simply conclude that Lipos will be most effiecient when being used in HVLA set up, like I am so happy with the lattest power set up by Avx 3638-2+5,2pgb+9s1p+18x12.5/ 20x12 props, that combo in my lenghten nose TWIN obviously goes much faster /powerful than the previous HALV combo which used 120+A ,10 cells combo.
For combo drawn over than 80A in normal size planes, even just short bursts, the batt will easily be heated up so quick and the accumulated heat will certainly affect the overall performance of any cells and this is also true to Ni based cells. In order to avoid high amp usage of Lipo and consume the Lipo packs bought recently, I have already changed out many hot set up (cold to most of hot rod lovers here) over 80A and subsquentially ordered more cold motors.
Ni-based or Li-based are designed / built for different purposes, so are their usages different too.
One more apparent improvement of Lipos I note is their efficiency in cost, street price of many of the 'NON BADGED/TOUTED', packs in China have been reduced a level 'cheaper' than the lattest gen. of top NiMH. eg IB4200,GP3900 and Gp4300.

Mar 26, 2006, 10:03 PM
Registered User
^ Most of the problems attributed to lipo fires can be eliminated by using one of the higher end chargers + a balancer.

I have to disagree about using higher C lipos in HP application though. If the past few years have shown anything, it's that lipo discharge rates can only continue to go up and discharge temperatures continue to go down. Pretty soon we'll see 20C cont, 30C burst lipos from the likes of thunderpower, polyquest, etc. Hyperion already has 30C burst lipos, although they're a bit heavier than the other brands.

I think Steve Neu posted some stats that compare the power output of lipos to NiMH, and it's amazing how close lipos are to overtaking them. And once lipos do overtake them, not only will they be lighter for the same amount of power, but they'll also double (triple? quadruple?) flight times

Originally Posted by treehog
with a mac you cant save from that site the vidio

proabably the same with pc windows x

vidio gallery or similar is better for saving film
gengg also posted it here http://www.gengg.com/rc/s14/s14partIII.wmv

it's wmv though so I'm not sure that solves your mac problem
Mar 31, 2006, 06:05 PM
UN Earth peoples true enemy
treehog's Avatar

Mac version of wmv works no problem

@Geoff Akerlund

it's wmv though so I'm not sure that solves your mac problem

Mac version of wmv works no problem

Its these flash sites like tube that seem to cause problems
I sopppose if you had flash software you could save the vidios

When I am offline traveling I like to loook at the vidios I have saved

The lipo's with the Mac give 4 to 6 hours run time for the laptop


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