leaderhobby LiPo packs? Has anyone experience with?

[neptronix]

This is me applying a 3.5A load to the battery, then turning off the load.

[ohzee]

man that's freaking crazy. yea good job exposing them for the crap they are.

[Bazaki]

What an amazing terrible bad looking discharge graph ! Those cells are useless for an ebike.

About the leaderhobby company itself, they send an C80-100- 130 kv motor pretty fast, so now we know that the cheap lipo cells are really bad but other products might be fine.

[neptronix]

They are even useless for a flashlight. Not sure entirely what they would be good for

http://neptronix.org/posts/dont_buy_unknown_chinese_batteries.html

I put up a full report here.

[cor]

Hi Neptronix,
Thanks for posting your experience - it seems I might be down the same path so I will certainly take your posted info into account.
The one thing that is different in my case is that my packs shipped in 4 (!) days:

This sounds like a good deal, but I was actually counting on the packs shipping slow boat,
because I won't be home for the coming 3 weeks...
Oh and the other grating thing is that they prepared the shipment *after* they confirmed that they would cancel my order, because I had finally read the horror stories here and requested cancellation. Well, the same "Amy" went for bonus points by first confirming to me that they would cancel the shipment and give me store credit; I came back and said that I preferred Paypal credit, then she told me that I should get credited within 2 days on my Paypal account, only to return and announce that the shipment was sent out anyway (and of course, no credit)...
Luckily I used my credit card (and Paypal) to pay, so I have some recourse if I also received re-packaged old 1C cells.
EDN just re-published a circuit to discharge cells with constant current and measure the time.
I have done similar measurements in the past to check 12V batteries with an inverter and a load of lightbulbs and a mechanical clock to measure the discharge time.
I wonder if I first should build a BMS and then do the discharge tests or first claim my money back... Definitely if I also get less than 4Ah from a claimed 10Ah pack, they will have to refund. We will see... in 3 weeks.

[neptronix]

Constant current discharge would be nice. I think a range of +/- 0.75A is not so bad if you don't need a dead-on accurate discharge, though. Can you gimme a link to the EDN circuit?

I did discharge at a constant 1A with my iCharger, i got about 5.75AH. It's hard though, because the cells sag intensely even at 1A. I cannot even get close to full capacity at 0.1C.

Sorry to hear you ordered these. You should do some tests and also post em up, but i have a feeling you're getting a pack full of 3-4 year old tekocell 1C, as i did.

We should start a class action refund battle with this company.

[cor]

EDN article for cell discharge (meant for NiCd and NiMH, that is why they recommend 1V cutoff, but it is easy to setup for up to 3V to use LiPoly by making R3 less than 10kOhm; I have ran the clock instead of from a battery, from 3 series diodes (with parallel buffer elco) and resistor off 12V)
http://www.edn.com/article/518463-Circu ... pacity.php
Just set the clock for noontime at start and it will indicate how long until the cell hit the threshold.
I like that the cell gets 100% disconnected upon termination.

[cor]

We should start a class action refund battle with this company.

That would only work if they are a USA company, methinks.
Do they have a US branch (local subsidiary)?
I see on their website that they claim to have a warehouse in Los Angeles and Miami
but there is no other contact into than Hong Kong.

[neptronix]

I don't mean legal action. I just mean mass refunds...

BTW, kinda funny. I'm past the 45 day refund period apparently.
It took about 45 days to ship it to me. I may have had a few days, but they were doing the stall tactic.

These guys are experts.

If you have recieved defective merchandises, please report it to paypal, at the very least.

[parabellum]

I am still missing 1 pack, will be 2 months in 1 week. Best thing I can do is not buy there anymore and give advise to others. ES be warned!

[neptronix]

Test your stuff and report to paypal if it is bunk. Leave a nasty message in the comment/message box.
You won't get your money back, but paypal will know that this company is ripping people off.

This builds a case against them and hopefully their account will be frozen.

[cor]

Test your stuff and report to paypal if it is bunk. Leave a nasty message in the comment/message box.
You won't get your money back, but paypal will know that this company is ripping people off.
This builds a case against them and hopefully their account will be frozen.

I plan to test their batteries before the 45 day period runs out.
My suggestion to all is to open a case within 45 days *even if you have not received your stuff yet*.
In that case you can claim a refund for not delivered goods (there is a reason for the 45 day cutoff)
and I will leave it up to your own conscience to do the right thing when goods do show up after
you have received a refund AND you find after testing that it is actually good quality....
In any case, opening a case in time will avoid that you lose right to a recourse for misrepresentation
as in this case, where old, low power and half deteriorated cells are sold as new high power cells!

[cor]

In case you are not aware how Paypal works: at the moment that you open a case against a seller, the amount of the sale that you contest is taken OUT of the seller's account and held by Paypal until the issue is resolved. Sometimes it helps your case to not immediately respond (don't wait longer than 3 days without at least posting that you are not available or traveling or such, or your case might get closed without your input) but since the seller cannot access (your) money, he has quite some interest in having the case closed if it is substantial money - the more cases open, the more money he cannot touch....
In retrospect, I believe that Neptronix should simply have claimed that he never received the article that he ordered.
It is true (he ordered something completely different than what he was shipped) and avoids the hassle over something that is unusable because a scam artist sends you a fake battery pack...
Look at it: the pack claimed 25C peak if I am not mistaken.
Even at full charge (4V) the internal resistance of 100 milliOhm limits the maximum power draw to 20A (cell sagging to 2V) which is only 2C peak.
Now who is delivering shrink-wrapped chemical waste in exchange for good money?
I agree - open a (Paypal or credit card) claim within 45 days of your order, no matter whether you tested the cells to be bad or you are still waiting for them.

[cor]

OK, I returned home to find a lot of mail and a box with 4x 4s LiPoly Transmetic 10Ah batteries.
Since the BVM-8s had also arrived, I decided to unpack the batteries and plug the monitor in.
Wow - bubble wrap was stuck to the foil that apparently was wrapped very recently around the stacks of 4 cells.
The foil was not particularly well cut, so jagged sides and general sloppy finish, but there seemed to be no puffyness of the cells.
NOTE that the cells are virtually unprotected in these packs, that is why they are so light - you are looking at the bare sides and
the flat sides are only "protected" by a thin layer of foil...
Anyway - plugging in the monitor showed that one pack had a bad cell (0.6V and falling quickly) and another pack had a bad connection in the monitor plug.
OK, testing the internal resistance: are these the same old cells that Neptronix received or are they any better?
I have a foglight from a BMW here, it draws about 5A at the pack voltage (14V) so just keeping the pack connected and monitor ready to beep when the cell voltage difference becomes too much or the voltage falls below 3V... OK, about 1.5 hours of discharge at 0.5C or about 7.5Ah.
Note that the battery was not fully charged, though all cells were between 4 and 4.1V, so there will be little improvement when fully charged.
Voltage drop at 5A is about 0.1V per cell. Not really great, but certainly usable, the cells do not get warm after 1.5h of 5A discharge.
I am certainly going to complain for not getting the capacity and the two not working packs.... To be continued

[neptronix]

Oh dude, you need to put up some pics. I gotta see this..

Voltage drop at 5A being 0.1v per cell is awful, that's a half C rating on a 10AH battery.

http://www.endless-sphere.com/forums/viewtopic.php?f=14&t=35668

I recently did a test on my 1 year old turnigy 20C batteries. I created higher internal resistance by sticking the batteries in the refrigerator and then my freezer. According to my tests, your battery is performing more like a 1-3C rate battery.

Maybe you have some tekocells in better condition, LOL..



Open up the pack and see.

After 45 days, you cannot get your money back via paypal. But you can create a huge stink and get another black mark on their record. The more people complain, the closer we get to freezing their paypal account for sending fraudulent products..

[cor]

Hi Neptronix,
I am *within* the 45 day period, so I hope to recover some of my money.
The one pack with the bad cell, I split in 2 (between the 2nd and 3rd cell)
and it was quite difficult to get the cells apart without damage or bending.
But I did not see the dreaded Tekocell printing. In fact, there was no printing at all.
Maybe both cells have it on the back, I will need to separate the cells completely then.
I was actually expecting to see the cells plummet like a rock, but was surprised that
they ran a 55W fog light for 1.5 hours straight until they hit 3V and all 4 cells stayed
pretty close together until near the end, when some stayed at 3.4V a little longer and
two others dropped almost at the same time to 3V.
I will need to measure the exact current draw from the fog light at 15V and charge
the pack back up to 4.2V per cell and repeat.
I'll post pics later, gotta run.

[cor]

Hi Neptronix,
Here some pictures:
The pack and my $11 Battery Voltage Monitor. It is hard to see, but the 2nd cell is at 0.5V and falling...


This is how a good pack looks like - even though it has all the characteristics of a sloppy hand-assembled pack: jagged cut foil, pasted on by hand (that is why the bubble wrap was sticking to it) and the label is sometimes put on one side, other have it on the other, so power wires can come out on right or left side...


The bad pack I tore the label and foil loose, then split the cells apart (did not disconnect the tabs) to look for markings.
As you can see in the picture, there are 4 different printed and hand-written labels on the cell, on top of or under the double sided tape that holds cells together, but not the dreaded Tekocell printing of an old 1C ancient-technology variant of LiPoly. I might actually have a second generation cells or so???


The front of the second (bad) cell.... looking OK, except for the large "fold" in the cell pouch due to the pulling of the double-sided tape and the cell is not exactly straight any longer, it is curved in length and over its width. Not sure if that is going to be a problem in future, because even though the cell was shipped at 0.5V it appears that it is taking a charge and showing reasonable internal resistance, in the same order of magnitude as the other cells...


Just for completeness - the back of the second (bad) cell, again no printing or marking, only pulled together foil from the double sided tape.


OK, now for the kicker:
It seems that the cell was at 0.5V because *it was never charged*!
The manual labor to assemble these packs makes the process vulnerable to error and it appears that they forgot all the normal checks, so one cell slipped through without being charged - ever. And made it into my pack. And that pack was shipped without ever being checked.
Now I hope that the cell can recover from being uncharged for so long - it appears to take a charge (see picture after more than an hour at 4A charging this one cell, it is at 3.8V and it can deliver 5A while sagging approx 0.1V like the other cells.... I will continue the charging to bring all cells in line (there was more than 0.1V of difference between the cells from the start, so I will also charge cell 1 extra - but cell 2 is looking promising, I hope it does not give a pyrotechnics show or develop high discharge or internal resistance - time will tell....

[cor]

There still is something going on with that bad cell - even though I have pretty much brought the pack up to equal voltages (all 4 cells are now between 4 and 4.1V) I noticed that while putting the pack back together that if I press down on the bad cell (or on the entire pack) then the voltage of the bad cell changes.
I am charging the pack at 1A so there can be an effect from changing internal resistance, but I did not see the other 3 cells change at all, only the bad cell showed a drop in voltage (not much, for example from 4.04 to 4.02, pressing harder across the entire length of the pack with 2 hands dropped the voltage to 4.01V). I am surprised to see this in one cell and the others stay at the same voltage. Hmm, maybe I should keep this cell compressed as it has seen some abuse now. Or is there a different effect on first charge of a cell? Or could it be that this cell *is* bad, was originally charged and will soon self-discharge to 0.5V again?
I don't like it when there are so many questions and no answers other than time will tell...

[parabellum]

Or is there a different effect on first charge of a cell? Or could it be that this cell *is* bad, was originally charged and will soon self-discharge to 0.5V again?

I had cells self discharging from start on but still performing well like others in the pack, I cut them out anyway since after few days they are lower voltage and revers charging in use can cost you entire pack or more. Leave it for few days and check the voltage again. 1 of my turnigy cells was loosing ~0.2V per week, so make no conclusions to quick.

[cor]

Hi Parabellum,
Thanks for the advice!
I will write down the voltages of my packs (they are not really well balanced as they arrived) and see if they change in the next days.

[cor]

OK, for your entertainment - here the voltages on the 4 Transmetic 10Ah 14.8V (4s) 10C LiPoly packs:
The first list is from the pack with bad cell 2, which I charged to 4.25V for a short while, now 4 hours at rest
Please understand that I manually balanced this pack already (charging cells individually) because the differences were much larger when I received it.
Originally cell 4 was the highest and hit 4.20V when charging all 4 cells at the same time. After that I have charged cell 2 separately, cells 1+2 and cells 1+2+3 but it looks like I now need to go back to the originally strongest cell 4 and prop it up a little too.
4.163
4.074 <- this cell was at 0.5V when I received the pack
4.173
4.111

This pack had a bad monitor connector. I discharged this pack at 5A, dropping to 4.5A until cell 4 hit 3.000V
Then I recharged the pack back to 16.6V (4.20V at cell 3) at max 8A until current dropped to 1A. No balancing done here (yet).
4.091
4.070
4.136
4.026

The last two packs were untouched, except plugging in the BVM (Battery Voltage Monitor a couple times and
a brief discharge test with the 5A load to check if every cell had decent internal resistance (every cell dropped about 0.1V at 5A discharge)
4.039
4.023
4.009
3.976

4.013
4.091
4.017
4.059

[cor]

Since I discharge-tested the 2nd pack without first charging it, I took pack 3 and charged it to 17V (starting at 4A dropping to 1A at the end), after giving a few boosts to individual cells to better balance them. I did notice that one cell (nr 3) has twice as much internal resistance as the other cells and was the first to go to 4.3V and the lowest on discharge. So, this pack is certainly not going to give high discharge current, but I am not planning to use it with very high discharge, so let's see what the capacity is while discharging it with an easy 5A. I tested my trusty fog light on my power supply to see how much current it draws and it is actually pretty flat, as you might expect from an incandescent bulb: 4.5A at 12V and 5A at 16V.
After an hour it seems that the capacity is not too bad - Cell 3 is still the lowest, but all cells are within 3.59-3.64V.
After one hour, 50 mins the two middle cells are at the same 3.40V level and start dropping faster, the difference with the other cells has increased to 0.1V at that point.
At 1:56 cell 2 is lowest at 3.30V and the difference with cell 4 has increased to 0.15V
At 2 the hour point cell 2 dropped through 3.2V
It reached 3.000V at 2 hours, 8 mins. This means, assuming that current was a conservative 4.7A that the capacity was exactly 10Ah.
Cell voltages at the switch-off moment: 3.31 3.00 3.10 3.37V and as you can see, the middle two cells went down rather close together, while the outside two cells stayed closer to the 3.4V level where the voltage drops less fast.
I am sure that at higher discharge levels, this pack (and especially cell 3) will hit the 3V threshold much quicker, but it is good to see that it has the claimed 10Ah capacity at low discharge level. With the high internal resistance of cell 3, even at full charge level (4.2V) that cell will never be able to give a peak 3C discharge in the first moments before falling below 3V, since I estimate the internal resistance at about 40 mOhm, so 3C (30A) will give a 1.2V drop. Nowhere near the claimed 10C discharge capability anyway.
Funny that while recharging at 10A, all cells are within 0.02V at 3.75-3.77V.
I finished the charging when at 17.1V the charging current dropped to 1A and the highest cell (nr 3) was at 4.304V.
After resting half an hour, all cells are within 0.03V again: 4.236 4.250 4.265 4.234 funny that the first and last cell are lowest - apparently they have larger capacity than the two middle cells. Oh well.

[neptronix]

Those sound like total junk as well.. you might actually have a useable product for non-ebike use.. i on the other hand, have some nice 0.001C cells

[cor]

I might actually try them on my ebike which is an EVG (EV Global) 24V bike that I plan to upgrade to higher voltage in future (but keep current severely limited to avoid burning up the motor, but allow assisting even at higher speeds, since I can pedal faster than the 24V bike will go). That is why I bought 4 packs of 14.8V so I can reconfigure them in 8s2p (29.6V 20Ah) or 16s1p (59V 10Ah). The first variant will never draw more than 1.5C from the packs because the fuse is 25A so peaks of 30A, split over 2 packs, might be light enough duty to use these packs.
For the single series string the current draw might be too high, we will see.

[cor]

I checked the cell voltages on my first pack (the one with the bad cell that initially was at 0.5V) and it seems that it is stabilizing. Initially that cell dropped fast (from the 4.074 after the first full recharge to 3.996 half a day later, but now 2 days later it has fallen only 0.008V to 3.988, while the other cells have fallen by between 0.003 and 0.005V but those were not cycled or completely recharged recently, just a little boosted. I will keep an eye on that cell, but it seems that it has recovered and may even be usable with a good BMS on the packs to keep 'em balanced as they seem not to be to well matched set.