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LiIon, LiPo, NiCd & NiMh General General Battery Support


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Old 02-28-2012, 09:27 AM   #1
Lee777
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Default Turnigy 6s Lipo 2mins flight time!!!!!!!!!

Hi All,

I have a turnigy 6s 3000mah for my trex 500, it is slightly puffed, and i mean very slightly hardly recognisable. I only get about 2 mins flight time and thats just steady hovering, when i balance charge it all cells come up the same volts and % but after flight :

cell 1 - 3.938v 64%
cell 2 - 3.814v 39%
cell 3 - 3.941v 67%
cell 4 - 3.940v 67%
cell 5 - 3.947v 68%
cell 6 - 3.941v 68%

What can i do to sort this pack out?? its only had about 8 flights??

Cheers All.
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Old 02-28-2012, 09:39 AM   #2
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It sounds like its dead. That is possible to do if you didn't break it in and over discharged it all 8 flights. (or if you did take care maybe you just got a bad pack?)
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Old 02-28-2012, 09:47 AM   #3
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Is there anything i can do to repair it????? or is it all scrap now????
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Old 02-28-2012, 09:52 AM   #4
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Sound like a typical packs end. Short flight times with voltage rebounding to nearly 4v/cell. Puffing. Did you follow the '80% rule'?
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Old 02-28-2012, 09:59 AM   #5
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yeah i got a lipo alarm and always check with a fusion digital battery checker cant see whats gone wrong but looks like cell 2 has had it
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Old 02-28-2012, 10:02 AM   #6
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It's far better to limit your flight time less than 80% capacity than to use voltage. (i.e. time your flights)

See how much your charger puts back in after a flight and make sure it doesn't put more than (in your case) 2400mah.
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Old 02-28-2012, 10:07 AM   #7
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I think it might have been a duff battery, it never been any good
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Old 02-28-2012, 12:49 PM   #8
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Your issue is cell #2 vs all the others.

Are you sure it is getting fully charged? The reason I ask is that when a cell starts to go south, usually its resistance goes up, so under load, the voltage from that cell drops. Afterwards, the cell will pop back up. What you are seeing is all the other cells look like they have lots of voltage, but cell # 2 doesn't recover.

There are two typical things--cell 2 isn't being fully charged. In that case it is the charger. You would see that on other packs, so I guess that isn't the situation in your case.

The second possibility is that cell has a relatively high leakage current. Some time after charging the pack, it just self-discharges and loses its own charge. I have seen that on a Turnigy pack a friend has. If he looks at the pack and cell voltage in the morning, after charging the previous evening, the one cell has lost a lot of voltage. He actually still uses it by charging the cell just before flying, and so it doesn't have a change to self-discharge. Did I mention he is pretty cheap?

2 minutes of hover isn't anything, and that cell isn't going to get better.
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Old 02-28-2012, 02:52 PM   #9
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Just balanced charged it at 1.2a and :
c1 - 4.203 99%
c2 - 4.121 93%
c3 - 4.198 99%
c4 - 4.196 99%
c5 - 4.194 99%
c6 - 4.196 99%

This is the only 6s battery ive got i will check the voltage in the morning to see if it has lost any.

i have a turnigy accucel 6 charger is there anyway i can just charge c2 on its own to max??? dont really wanna throw it away
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Old 02-28-2012, 04:10 PM   #10
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Quote:
Originally Posted by Lee777 View Post
Just balanced charged it at 1.2a and :
c1 - 4.203 99%
c2 - 4.121 93%
c3 - 4.198 99%
c4 - 4.196 99%
c5 - 4.194 99%
c6 - 4.196 99%

This is the only 6s battery ive got i will check the voltage in the morning to see if it has lost any.
Are you sure you are using LiXX BALANCE mode to charge that pack? See attached.
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Old 02-28-2012, 04:52 PM   #11
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Gregor 99, ive got the ACCUCEL 6 not the 8, mine has not got LIXX on it just lipo balance, i always use the lipo balance.
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Old 02-28-2012, 04:58 PM   #12
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Gregor 99, ive got the ACCUCEL 6 not the 8, mine has not got LIXX on it just lipo balance, i always use the lipo balance.
Well if thats the best it can do then cell 2 is stuffed.
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Old 02-28-2012, 05:17 PM   #13
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Quote:
Originally Posted by Lee777 View Post
Gregor 99, ive got the ACCUCEL 6 not the 8, mine has not got LIXX on it just lipo balance, i always use the lipo balance.
Sorry I mislabled the image, that is actually from the ACCUCELL-6 manual. If you are using balance mode, the charger should be able to do better than that. I'm surprised the charger finished with one cell like that. You could try slowing the charge rate down. The balance circuits on the chargers is very low. Usually between 200ma and 250mah. Put it on a slow charge at 250ma for hour or so and see if the voltage comes up.

However if the charger is able to get that cell to 4.18v-4.20 and the cell quickly drops back to 4.1v then its likely that cell is dead.
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Old 02-29-2012, 02:08 AM   #14
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I charged the pack last night and cell 2 was 4.136v and 95% i left it stand for 8hrs and checked it this morning and cell 2 has dropped to 88% so it isnt holding the charge can it be repaired or have i just got to charge it and use it right away?? Whats caused this? is it a manufacture fault? cheers.
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Old 02-29-2012, 09:24 AM   #15
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Quote:
Originally Posted by Lee777 View Post
I charged the pack last night and cell 2 was 4.136v and 95% i left it stand for 8hrs and checked it this morning and cell 2 has dropped to 88% so it isnt holding the charge can it be repaired or have i just got to charge it and use it right away?? Whats caused this? is it a manufacture fault? cheers.
You can do like my friend, but you run the risk that at some point it might just completely die on you--like in the air.

You have to understand, we are not lipo experts, just lipo users. At least for me, I read and listen and try to apply what seems to be reasonably accepted lipo practices. You also have to understand that lipos have evolved, so todays lipos have (some) different characteristics than those from 5 years ago. Future ones may be different too.

Common sense says to not trust that lipo. Maybe you can keep using it with no danger, maybe not. I ask how much is the rest of your heli worth? Is it worth the risk?
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Old 02-29-2012, 10:09 AM   #16
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Quote:
Originally Posted by ahahn View Post
You have to understand, we are not lipo experts, just lipo users. At least for me, I read and listen and try to apply what seems to be reasonably accepted lipo practices. You also have to understand that lipos have evolved, so todays lipos have (some) different characteristics than those from 5 years ago. Future ones may be different too.
I just had to pop in and say WELL STATED ahahn!

As to the OP, everything you have shown so far leads us to believe you have a bad lipo. Dispose of it properly and replace it. You might consider buying a lipo with a warranty next time.
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Old 02-29-2012, 02:09 PM   #17
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Charged the lipo at 0.6, took a while but all cells came out the same,used the battery as soon as it charged and it lasted about 4 and half mins but cell 2 still down lower than the other cells when i disconnected the battery, will keep this pack just for a warm up pack for trimming and a bit of steady low level hovering, i will keep a close eye on the pack for any swelling or very low voltage and if gets any worse will have to dispose of it. Thanks for all your help, ive learnt a bit more about lipo's now.....
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