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› Turnigy 6s 5000mah 25c lipo problem.
08-11-2010 05:41 PM  7 years agoPost 1
Busher

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Manchester, England

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Hi there,

Just bought 4 of the above batts from HK and one of the packs has caused me some concern.

First off my hyperion 610 net gave a cell failure alarm on cell 4, I took it off and took a reading with a dvm from the balance tap and it was showing only 1.3v Being a brand new pack I Thought it may just pull its self round with the first charge So i put 1/2 an amp into it and sure enough the cell recovered to some extent and completed a charge albeit out of balance the finished cells were all about 4.2v but cell 4 was about 3.91v.
The pack was used and it gave reasonable performance but died quickly towards the end of the flight.
I re charged with no problems and then decided to cycle the pack and watch the voltage. cell 4 got to about 3.65v then fell to 0v and I mean 0v, then when I disconnected the charger the cell voltage slowly raised itself to 1.2v and from there I have not gone any further.
Can anybody throw any light on what could be the problem and or whether the pack should be discarded ?

It looks like an internal cell short but it appears transitory to allow it to charge but not fully, then to fall to a specific voltage then collapse to 0v i am a bit confused.

Good luck
Busher

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08-11-2010 08:07 PM  7 years agoPost 2
Kiba

rrApprentice

CA

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Cut the shrinkwrap off and directly probe the suspect cell's heavy solder tabs with a voltmeter to rule out the possibility of a bad balance lead/connector.

If the cell is bad directly at the tabs consider it toast. You can buy single cells from HC and do the replacement yourself-- I've done it before. You need to use caution though not to short either the entire pack or the individual cells while desoldering and resoldering.

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08-11-2010 10:19 PM  7 years agoPost 3
Busher

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Manchester, England

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Thanks I will give that a go when I get few mins spare, Never thought it may be bad soldering in the pack or a dodgy balance connection.

Good luck
Busher

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08-12-2010 12:09 AM  7 years agoPost 4
flyride

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Salt Lake City UT

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You could charge it up and then put it on a balancer and see if it brings the other 5 cells down to the one that is low so they are the same voltage then try to slow charge them full and see it that will bring it in line. Just a suggestion after the solder check... Good luck I hope it works out the battery is to expensive to just toss.

and the blonde said "RECTUM, Hell damn near killed em!!"

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08-12-2010 11:31 AM  7 years agoPost 5
Richardmid1

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Leeds, England

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I have had about 5 turnigy li-po's and never got them to balance correctly! I was about to post a new topic explaining my annoyance about this when I saw this post first.

THE LIFE AND PERFORMANCE OF A PACK SOLEY DEPENDS ON HOW WELL IT BALANCES FROM THE GET GO!! Forget about it being balanced within at the end of a charge that is irrelevant.

Instead of C ratings I would like to see cell imbalance figures when I am purchasing a pack and the packs being priced accordingly!!!!! It would not be difficult for the manufacturers to do this!

60% of the time, it works every time!

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08-12-2010 02:31 PM  7 years agoPost 6
Busher

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Manchester, England

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I have had about 5 turnigy li-po's and never got them to balance correctly! I was about to post a new topic explaining my annoyance about this when I saw this post first.

THE LIFE AND PERFORMANCE OF A PACK SOLEY DEPENDS ON HOW WELL IT BALANCES FROM THE GET GO!! Forget about it being balanced within at the end of a charge that is irrelevant.

Instead of C ratings I would like to see cell imbalance figures when I am purchasing a pack and the packs being priced accordingly!!!!! It would not be difficult for the manufacturers to do this!
I would have to agree, and it would seem that you get what you pay for.
If we were to buy new lipo's what would be your recommendation for a purchase based on your own experience. I can only give my opinion on flightpower and turnigy at the moment.It does however appear my pack may be toast. But there is a possibility to make a 4 or 5 cell out of what is left?

Good luck
Busher

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08-12-2010 02:46 PM  7 years agoPost 7
Richardmid1

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Leeds, England

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It is a gamble purchasing li-po's on the internet. My LHS would be happy for me to take a cell voltage checker or stand alone balancer into the store and check the balance of the pack before I buy it. Even if I buy it first and while still in the store open the packaging if there is any and check the balance there and then. If it is way out they should replace it. Ide recommend everyone does this when purchasing li-po's over the counter.

60% of the time, it works every time!

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08-13-2010 03:14 AM  7 years agoPost 8
whbell

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Melbourne, FL - U.S.A.

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If I had an LHS with a stock of batteries that I needed, I WOULD purchase from them with the expectation that each pack worked. For those of us in the boondocks, what is the real solution?

Gravity is what makes flying so much fun!

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08-13-2010 05:57 AM  7 years agoPost 9
kcobra

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St. Louis, MO - USA

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It's not purchasing LIPO's over the internet that is the gamble. It is purchasing them from various sellers such as Hobby King. I imagine there are US sellers that are just as shady.

There are reliable lipo's out there with dependable warranties from reputable sellers. Hyperion batts from allerc.com comes to mind.

Now with all that said each person has to decide if the cheap price from HobbyKing and the like are worth it. For me if the shipped price is ~60% or less for the HK lipo's compared to Hyperion cells then it is worth it. Of course if I was a heli pilot instead of a car guy I might think differently.

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08-13-2010 06:07 AM  7 years agoPost 10
G Steyn

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Heidelberg, Transvaal, Suid Afrika

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Approx a month ago, I took the risk of purchasing my first Hobby city packs...

The packs arived in good balanced cond, one of the packs slightly puffed...(Turnigy 6s 5000mah 35c)

After approx 2 cycles, one of the un-puffed packs had a cell (no 4)that measured under 1 volt! Cell 5 measured 3.75. That is when the rest was standing at 4.19v.

I was a little bit frustrated. None of my Li-Po chargers wanted to even look at charging a 1v Li-po. I then hooked that one cell up to a Robbe constant current Ni-Cd charge of 0.25a, until I got 3.2v out of the cell, and I could finish the charge on a Li-Po charger.

So far so good, the packs are approx 5 cycles later, and every cell balances perfectly, with an internal resistance of under 2 mili Ohm.

NB: I WOULD NOT RECOMMEND THIS METHOD TO ANY SANE PERSON OUT THERE....

Concentrate on your weaknesses and your strengths will reward you!

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08-13-2010 08:38 AM  7 years agoPost 11
Busher

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Manchester, England

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Well it looks like a cell problem. The internal soldering on this pack is as good as it gets. So I will start having a look at disassembly of the pack in order to get a good pack out of what is left.
I have tried the small constant current route but the way the pack dies at the end of the flight it acts like a forced Auto. Not good if you can't be sure where it will cut out on you.

I got the packs at a very good price in a flash sale, I can't complain, If I had bought cells over here they would have cost circa £800, I paid about £170 for 4 packs, so one wrong doesn't seem too bad. I may look out for better prices in the uk and in future buy from over here. But the price was king on this occasion.

I was a bit stuck around christmas time, My wife bought me a Kontronic speed controller, which at the time due to its cost she thought was a helicopter, Imagine her surprise when the box turned up. I received it for christmas and then was forced into having to buy the rest of the heli (logo 500 3d) to allow me to use her christmas present. The arguments and bad feelings would have been too much otherwise.
So I ordered the batteries to see 1, what the service from HK was like and 2,how the batteries would perform. I am now firmly hooked on electrics and will probably invest accordingly when these Turnigy's give up the ghost.

Good luck
Busher

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08-13-2010 10:54 AM  7 years agoPost 12
Richardmid1

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Leeds, England

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I too have charged li-po's on a Ni-Mh charge to get the cells back upto over 3v per cell and I believe it is safe to do so as long as you dont leave it on charge too long!

60% of the time, it works every time!

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