Turnigy 4s 5Ah Hard Case 20C Lipo, review in the works

[miuan]

I got 5.6Ah from a random cell from 4.2V to 3.0V that was about 8 months old. I really love them.

[bobale]

Mine are 10 months old, and I've pounded them more than few times with 40-50A discharge on 1P, and expected them to give 5Ah at most. It seems they are better than I've expected.

[chessir]

I bought 2 of these about 1.5 months ago . Ran great for a couple days in series but then suddenly both went down to 7.4v . Not sure if I left the controller hooked up or not. I was successfull opening one case without much difficulty. Can someone advise how to measure the individual cell voltage with a multimeter? I see 4 distinct cells connected by 5 blobs of sodder. Each of 4 corners has a blob connecting 2 adjacent cells and there is blob in the middle . If I have 7.4 volts then the average cell voltage would be 1.85v. Does that mean they're all dead or can I slowly recover with a single cell charging technique? What would I use as a single cell charger?
I do have an old cell phone charger I could put to use if neccessary.
When I connect the pack to my i-charger I get ERROR- Low voltage.

[bobale]

You don't need to open battery case to measure individual cell voltages. That's what balance connectors are for. Anyway, it's now pretty much late to anything. If you slowly discharged them by leaving controller on and they haven't puffed you can try to trickle charge them, but they are not to be trusted anymore. If you give it a go at charging do that outside and at fire-safe place, because charing overdischarged LiPo is almost certainly going to end in a huge fireball.

If you want to charge them use charge only mode on your charger (without connecting balance connector), and select 2S, then 3S, and that way you'll slowly bring up the voltage. Select low charging current, start with 0.1A.

[parabellum]

Take notes of every cell voltage before doing anything. There may be few cells over 3V but I have doubt about it, because they usually are matched very well. Anyway if some cells are way lover then others, they probably will be first to cause problem, if any is reverse charged cut it out. I actually have over discharged 15 packs to 1.8-2.8V every cell and overcharged 3 packs to over 4.6V every cell. They puffed a little and go out of balance quick but I still use them at my own risk. Some of them over 100cycles after accident.

[chessir]

Hi , Thanx for responding. I still need to know how to measure the individual cell voltages. Do you do this through the tiny little holes in the balance connector by inserting a pin or needle in the positive hole and the negative cell hole? Or do you do this on the sodder blobs on the opened pack? If so where would my positive and negative multimeter probes go? And could you also charge an individual cell through the balance connector?

[parabellum]

Try this way. Every 2 adjacent contacts is 1 cell. In represented picture I measure voltage of last cell in series, where count starts with negative end.

[parabellum]

And could you also charge an individual cell through the balance connector?

Yes you can, but I would not pas over 2A

[Ypedal]

when doing what is pictured above with the volt meter, i suggest using electrical tape and covering the probes leaving only the very tips exposed... prevents occurence of sparks !

[chessir]

Hi Para:

Thanx for the nice pictures. I measured my 2 hardpacks with following results
Pk#1 cell1- 0.00 cell2-0.00 cell3- 3.64 cell4- 3.66
Pk#2 0.07 0.07 3.65 3.67

How did I accomplish this by accidentally leaving them overnight with controller connected? I remember on a prior occassion I briefly shorted wrongly connecting the Pos & Neg of the battery power leads to the controller. I remember getting a sudden jet-like emmission out of the serially connected packs.Perhaps this caused damage to the 2 cells in each pack. The packs seemed to work fine when I properly reconnected.
Should I try to recover the 4 cells each individually thru the balance connector at ca 0.2 amps with my charger or like you suggested bring the total voltage up with the charger set at ca 0.1 amp and no balance lead connection?

[JimW]

auraslip,

Can you tell me the significance of the Red, Yellow and Green on your spreadsheet. I understand that they represent the cell voltage, but what conclusions do you draw from the voltages. Does red indicate a bad cell, or just a low voltage one? How low a voltage would you consider to indicate a bad cell? Or what kind of voltage and discharge curve would you like to see to confirm a good cell.

Sorry for all the newbee questions.

Thanks,
Jim.

[bobale]

Chessir, forget what I've told you about charing them. If you charge cells below ~2V it can only end ugly. If you want to salvage other cells just separate them, you have a lot of guides here.

[chessir]

Chessir, forget what I've told you about charing them. If you charge cells below ~2V it can only end ugly. If you want to salvage other cells just separate them, you have a lot of guides here.

Hi bobale:

Thanx for responding. I thought I read somewhere that you could slowly individually rejuvinate bad cells at very low amp. out in the open and away from destruction in case of disaster but that was for non-hardpack packs. With hardpack packs the result could be different and worse and I doubt anyone tried on hardpacks to bring back 0.00v cells. So, thanx , I will take your advise.

[parabellum]

Chessir, forget what I've told you about charing them. If you charge cells below ~2V it can only end ugly. If you want to salvage other cells just separate them, you have a lot of guides here.

+1

[parabellum]

Pk#1 cell1- 0.00 cell2-0.00 cell3- 3.64 cell4- 3.66
Pk#2 0.07 0.07 3.65 3.67

That looks suspicious, how are you charging them? I can not imagine that they were balance charged and if then your charger must be faulty.

[chessir]

Pk#1 cell1- 0.00 cell2-0.00 cell3- 3.64 cell4- 3.66
Pk#2 0.07 0.07 3.65 3.67

That looks suspicious, how are you charging them? I can not imagine that they were balance charged and if then your charger must be faulty.

I'm quite 100% sure I balance charged them before use but as I stated I accidentally miswired when I connected to the controller the day prior to use. This shorted and emmitted a jet out of the series pack. I then rechecked the cells on the charger to see if they were OK and all cells were perfectly balanced.

[parabellum]

Next time you balance charge healthy pack, check individual cell voltages. I have received HK charger that is measuring 1 cell 0.05V over its real voltage. I am sure it is not the worst case of QC in HK.

[chessir]

Next time you balance charge healthy pack, check individual cell voltages. I have received HK charger that is measuring 1 cell 0.05V over its real voltage. I am sure it is not the worst case of QC in HK.

Hi Parabellum:

Oh! So your're saying after balance charging then confirm cell voltages by readings off the battery balance connector like I just learned how to do? Sounds like a great idea to me especially with less reliable HK chargers. Thanx

[bobale]

You should definitely get one of these: http://www.hobbyking.com/hobbyking/stor ... duct=10952

[chessir]

Hi Bobale:

Yes, I've been meaning to get one of those cellog 8 monitors.Lately I've gone to using an hk-010 portable balancer and monitor which seems to give much more accurate readings than the "cell checker" I had been using.The cellog 8m I know are popular here.

[auraslip]

popular may be an understatement. i'm sure most of us have at least one. i... only have four

[JimW]

I think perhaps my question got lost in the shuffle..

auraslip,

Can you tell me the significance of the Red, Yellow and Green on your spreadsheet. I understand that they represent the cell voltage, but what conclusions do you draw from the voltages. Does red indicate a bad cell, or just a low voltage one? How low a voltage would you consider to indicate a bad cell? Or what kind of voltage and discharge curve would you like to see to confirm a good cell.

Sorry for all the newbee questions.

Thanks,
Jim.

[parabellum]

I think perhaps my question got lost in the shuffle..

auraslip,

Can you tell me the significance of the Red, Yellow and Green on your spreadsheet. I understand that they represent the cell voltage, but what conclusions do you draw from the voltages. Does red indicate a bad cell, or just a low voltage one? How low a voltage would you consider to indicate a bad cell? Or what kind of voltage and discharge curve would you like to see to confirm a good cell.

Sorry for all the newbee questions.

Thanks,
Jim.

Those are just randomly taken colors 1 for every cell in 4s pack.

[auraslip]

I think it's a rule set up to show weak (red), not as weak (yellow), and not weak cells (green)

[parabellum]

I think it's a rule set up to show weak (red), not as weak (yellow), and not weak cells (green)

Sure? Then what is this?


Edit. Sorry aura, my bad, he is apparently talking about spreadsheet.