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Old 07-01-2010, 01:08 AM   #31
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Given that almost all brands of batteries have had problems, the explanation could be nell'ESC, some ESC does not have an efficient cut-off and create problems of low voltage to damage the battery regardless of brand.
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Old 07-01-2010, 02:23 AM   #32
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Given that almost all brands of batteries have had problems, the explanation could be nell'ESC, some ESC does not have an efficient cut-off and create problems of low voltage to damage the battery regardless of brand.
Your on the right ball path but not quite there .The problem is with the discharge of the battery and the demand from the esc .Now its tricky some of you can do the calculations and some can't but what happens when you do the calculations and you get a figure ok that you need atleast 50C continues for the esc to operate at it max performance how would you know if the battery you just purchased is a true rated 50c or is it a 35c labelled 50C or is thr esc truely rated at 150 amps continues or really 200 amps .

see the problems is you will never know and thats when it gets frustrating .

Next month i will be in china at the military factory owned by the chinese goverment in xian city so i will look at the production and bring back info and photos on how the c rating is developt within the grid of the battery ok so then everyone will understand even myself i will learn more and pass on the info to you guys .
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Old 07-01-2010, 02:54 AM   #33
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Ok guys ive worked out a good example ok .

now say for example the max current rating of your brushless motor is 100 amps thats the maximum your motor can ramp up to and can handle .

your battery is say 50c continues discharge and say 100c burst ok and capacity of your battery is say 5000mah .

now what you do is the following so your burst is 100c so you mulitply the burst current by the capacity ok .100 x 5000mah = 500,000mah ok

Then you multiply the continues current discharge of 50c and the capacity of 5000mah 50 x 5000mah =250,000mah .

Now because its rated in mah do the following as you know 1amp =1000mah ok so what we do is this 500,000mah/1000mah =500amps this is for burst current in 30 sec max ,then you have continues current at 250000mah/1000 =250amps so you can see that the motors max is 100amps of current at its peak but you have 250amp of continious current and 500amps of burst current for max of less than 30 sec .

which inturn those numbers tell you that you have more than double the enough ofconitnious discharge current according to your calculations from your battery to run a 100 amp max peak motor .so imagine your motor needed 300 amps to operate then it would only operate with burst current for only less than30 secs before the esc and the battery finally die or shut down.

so what im getting to are the motors we are running especially mod motors correct specs are our batterys correct specifications as dont forget the esc is the middle man in this project and will give the motor the maximum it demands until the esc shuts down or burns out one or the other will happen .Now if the battery cannot handle the amount of current the motor and the esc need to run at its maximum rating and performance thus the c rating then the battery will get damaged causing extreme heat and leaking cells which inturn will cause your batterys to puff not immediatly but after a couple more chargers and dischargers .

I hope i havent confused to many poeple all im doing is only trying to help most of you to understand that if you want the max performace out of anything thats electronic all parts of the project must match from the battery to the esc and the motor .

Sorry for using large numbers in my calculations i always do that something i think that i need to stop . sorry guys

regards Angelo
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Old 07-01-2010, 03:06 AM   #34
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man am even more confused now

i wanna run 4.5/5.5 motor with a speed passion GT 2.0 Pro esc, what battery do you guys recommend???

any help is highly appreciated.

Ali
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Old 07-01-2010, 05:13 AM   #35
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eh?

I have 4 puffed IP 5000 50c packs and they have only ever powered a x12-17.5 and tekin rs pro esc in a xray t3. These packs were bought new for the WA state titles (25 april 2010). a 5 minute run would use 2100 out of the pack.

Ignoring the maths, are you saying the esc is damaging my packs or are saying the current range of lipos are not up to the task of supplying power to the motor?

Not having a go at you Cobra but spending 400 bux on packs only to have them puff up after 2 months is annoying to say the least. Llast year I ran (badly) 10.5 for the most part on 2 year old LRP 5300 28c packs without any of the puffed lipo issues we now see. I for one dont plan on buying IP's and will probably use them till they split the casings. Hopefully a solution is found before that happens.
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Old 07-01-2010, 06:24 AM   #36
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Wow cobra, you couldn't have found a more confusing way of saying what you said if you really tried. In fact because of how you put it, I got no idea what you actually said.
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Old 07-01-2010, 06:40 AM   #37
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The maths is ok, just ignore the zero's. If you are running a 5000 - 50C, just multiply 5 by the C rating. ie 5 times 50 equals 250. That's the max this battery wants to put out in amps - 250 amps. This is continuous current, not max.. but thats as per what Cobra said above.... But anyway, I run stock, 17.5, and I stand corrected, but I did not believe a stock motor pulled anywhere near 250 amps..... I know heat, ie the motor getting above... say around 60 degrees C plus can effect the amps... add to this the incredible speedies we now have... and maybe the combinmation does add the the puff equation.... no idea but what I would like to know is how many puff battereis through normal use....?

If you store a battery full or leave it in the sun.... that is not the manufactures fault when if puffs. And just quietly, I do not think trying to discharge them, or charge them at more than 1C (yes I know you can) is a good idea and very advantages to prolonged battery life...

Is it just the higher C ratings people are puffing, predominately 45 and 50's...
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Old 07-01-2010, 06:56 AM   #38
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When I race in 10.5 I use about 2000mah in just over 5 min. Thats an average of around 22amps. I haven't run my data logger yet so I can't be too sure of peak amp draw, but its probably not much more than 50 - 60 amps. If the reason these lipo's are puffing is because of too high a current draw, then they are lying about the C rating A LOT!

I don't think thats it though. I've seen boats drawing 100amps with Thunder Power 25C's a few years ago and these problems didn't exist. There is no way our cars are abusing lipo's like boats and planes do. I think cobra is right when he suggests quality control is the issue.
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Old 07-01-2010, 07:21 AM   #39
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Quote:
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Wow cobra, you couldn't have found a more confusing way of saying what you said if you really tried. In fact because of how you put it, I got no idea what you actually said.
sorry dude i didnt mean to confuse you but it always seems like i go to deep sometimes in trying to explain things sorry .I use to do the same thing at Qantas when i was an engineer the guys use to say wtf are you on about lol but it was always correct but just overboard .

Anyway even 25c and 35c lipos swell as well its not only the 40c and 50c packs .
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Old 07-01-2010, 07:31 AM   #40
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Originally Posted by COBRARACING View Post
sorry dude i didnt mean to confuse you but it always seems like i go to deep sometimes in trying to explain things sorry .I use to do the same thing at Qantas when i was an engineer the guys use to say wtf are you on about lol but it was always correct but just overboard .

Anyway even 25c and 35c lipos swell as well its not only the 40c and 50c packs .
No need to be sorry. I was just taking the piss a litle. In fact I appreciate your advice on the subject and am sure I'm not the only one. It would be great to finally understand the truth about the lipo war.
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Old 07-01-2010, 08:24 AM   #41
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Since no one seems interested in answering my question, i just order Thunder power's G4 5200 50C. i wanted the bullit connectors but it comes with deans. since Paul run them, they should be good
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Old 07-01-2010, 09:28 AM   #42
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Stating that the main and only reason that Lipos puff from RC CAR applications is from the amperage demands is completely off target.

Stick a data logger on any RC car. Peak loads during max acceleration from a highly boosted 13.5 motor is a hair over 50 amps. This is a peak current and is never sustained. Average current over a 6 minute run is about 25 amps. For 17.5, the amp draws are much lower.

This is well under the capability of just about EVERY hard cased lipo, even those with inflated C rates. Even a 15C lipo will easily handle this current range.

Running a lipo over it's usable current results in very high temps. Over 180 deg and the electrolyte starts to break down and forms gas. Temp a lipo after run and it's nowhere near this temperature.

So what causes a lipo to puff?

Lot's of reasons and each has it's own specific failure modes. Here is a list - mostly likely incomplete.
  • Immature Formation Process:
  • Insufficient Hi-Pot testing during the electrode stacking process
  • Insuficient or non-existant incoming material inspection
  • Insufficient contaminant filtering of the slurry raw materials
  • Bad pouch seal or badly designed pouch seal
  • Overcharge
  • Overdischarge
  • Overcurrent
  • Overtemp

My guess on why a bunch of lipos are puffing is due to the immature formation process. This process is highly proprietary to each manufacturer. This can take anywhere from 4 days to 2+ weeks depending on manufacturer. This process takes years to master. A lot of these lipo companies are very new and their formation process is immature. Combine this with a new untested chemistries and you have long term issues.

Sorry, for this tangent to a thread titled "Intellect 50C thread"
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Old 07-01-2010, 09:41 AM   #43
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I stand corrected! Well that makes things a whole lot more confusing. Does anyone know of a brand that doesn't have this problem?
Sadly, no........I think if we look or wait long eneough, somewhere, somehow, someone has a puffed pack of every brand. I like TP too, if not for any issues, they still have top notch customer service.
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Old 07-01-2010, 09:44 AM   #44
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Originally Posted by KWT-NITRO View Post
Since no one seems interested in answering my question, i just order Thunder power's G4 5200 50C. i wanted the bullit connectors but it comes with deans. since Paul run them, they should be good
Sorry, a good choice.
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Old 07-01-2010, 09:50 AM   #45
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Originally Posted by Johnny Wishbone View Post
Sadly, no........I think if we look or wait long eneough, somewhere, somehow, someone has a puffed pack of every brand. I like TP too, if not for any issues, they still have top notch customer service.
After I read that thread, I realized it was only 1 or 2 people and they were taken care of very well by Thunder Power. Everyone I know who has tried a TP says it is better than the rest and none have had problems. They might be a bit more to begin with but will save you money in the long run.
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