Batteries running-in and swollen batteries (Full Version)

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najary -> Batteries running-in and swollen batteries (9/15/2012 9:23 AM)

Hi all,

What do we know about battery running-in?

Is it really necessary at all?

I know what running-in does for I.C. engine, but what does it do for battery?

Up till now, according to the battery distributors recommendations, I used to fly a new battery 5 times with not more power than half throttle.

This is an unpleasant process; especially if you don't understand why it is needed and what it does to the battery.

Lately a friend of mine told me that his friend, someone who works in the U.A.V. industries, told him that that type of running-in (fly 5 times with not more power then half throttle) does not do any good for the battery.

He claims that a real running-in process is: charge the battery at about 0.5 C and discharge it at about 0.2 C, 5 times.

My friend told me that since he started to run-in his batteries this way, his batteries do not become swollen during the time.

I will be glad to have your responses to the above.

Best regards,

Isaac Najary



rcflyer4fun -> RE: Batteries running-in and swollen batteries (9/15/2012 11:34 AM)

Yes great question. I just got my first electric plane and I am interested in the subject.



nonstoprc -> RE: Batteries running-in and swollen batteries (9/15/2012 12:55 PM)

Seems this is a good article on the subject. It is here.

As explained, water in the mix, over-charge or over-discharge, and poor separator construction are the three reasons for a swelling lipo pack.



mups53 -> RE: Batteries running-in and swollen batteries (9/15/2012 1:44 PM)

 Wow what a great article. I feel smarter now.
 Isaac I use a Cellro Power Lab 8 charger to break in my packs. I charge at 1C and discharge at 20 amps. I do this to all my new packs and it saves a lot of painful flights that waste time. I cycle it 6 times. Mike



rm -> RE: Batteries running-in and swollen batteries (9/15/2012 3:49 PM)

I use an old actro outrunner I don't fly any longer mounted to my bench with a small prop.  Hook up my hyperion logger and run it through my laptop in real time mode.  That way I know what amps are being pulled, voltage, and mah out.  I only do it a couple times as I don't have the patience, and then go fly just not using any extended wot for a couple flights. 



Bill Clark -> RE: Batteries running-in and swollen batteries (9/16/2012 4:24 AM)

I charge at 1c then discharge to 3.75v at 1amp 4-5 times. by then the cells are balancing well (like .000). then I fly the pack kinda easy for the first couple of flights using 1/2- 3/4 of my normal flight time then use them normally.  this has worked well for me after 6 years of electrics with long service lifes on anything from TP's to cheapos. over discharging is the only definitive cell killer I have found so far or running a pack that doesnt have a high enough "c". the rule I use is my max current should not exceed  the advertised continuous discharge rating and preferably 80% of that. If the cells arent real happy at the end of the initial bench cycling i dont expect them to last long



wagen017 -> RE: Batteries running-in and swollen batteries (9/16/2012 7:15 AM)

I really wonder about this "running in" story. I think it depends on the failure mode. I recognise at least three different ones:
- indivudual cell unbalance versus the rest of the pack. This effect will be greater when reaching maximum discharge (<3V).
- increase of internal resistance over time resulting in reduced Max C delivery
- reduction of capacity over time

Running in packs IMHO has the effect that you take more care the first few runs in charging/discharging which will help in detecting failure mode #1. I have had other packs that i never run in, actually were discharged fullu serveral times to the max and still ran fine upto 300 cycles, only with some reduced total capacity.
I've had other packs I really carefully ran in which I retired after 100+ flights due to increased Ir.

The link provided gives some great insights in what influences actual pack build quality. That initial quality will have much greater influence that the running in methodology used.

Volkert



Silent-AV8R -> RE: Batteries running-in and swollen batteries (9/16/2012 2:34 PM)

I install the connectors I want, charge, and go fly.

I do three things that seem to work for me:

Buy proven cells
Rarely discharge beyond 75%
Charge at 1C

I stop using a pack when it starts performing poorly. I have never had a pack puff or stop balancing properly. This includes when I was racing boats where I had a 10S2P 10,000mAh (5s-5,000x4) set up that I ran down to 75% inside of 2 minutes. In fact, those packs are 5 years old now and I still use them for practice.

Of course, with the cost of lipos these days I almost look at them as disposable compared to just a few years ago when you had to mortgage the house to buy a couple of them.



nonstoprc -> RE: Batteries running-in and swollen batteries (9/16/2012 2:41 PM)

My experience has been that some brand new packs are defective on arrival. The best way to detect is to fast charge the pack as it will be charged later on. A pack with at least one cell super slow to take charge is defective and should be returned.

On controlling of swelling which is inevitable, it seems a good practice is to avoid over-discharge (e.g., discharge it too fast, at a higher rate), for the packs at hand. Use of a low pitched prop (e.g., 20.5X13 instead of 20.5X15), flying the plane slow, and proper throttle management do help.



EHFAI -> RE: Batteries running-in and swollen batteries (9/16/2012 5:09 PM)

I don't know if break-in is good or irrelevant, seems like it's a good idea. I break-in new packs on a test stand where I can monitor individual cell volts and overall output. Stand is equipped with a low cost motor that can handle 30A for 6 min. Packs are allowed to cool completely before charging after each run and the process is repeated 5X. Using brand name packs I've not experienced any early failures - but it may not be absolutely necessary.

A much more important practice as packs age is to check the individual cell volts at the beginning of charge. The balance connectors on packs (and any extensions) deteriorate with use and can provide false info to the balancing circuits of the charger. Of course, that means the balancing attempts of the charging system will be in error, possible over / under charging some cells. Kinda defeats the purpose of balancing! It's very important to determine if errant cell voltage is correct or a connector problem before "mis-charging" the pack! Sometimes cleaning the connectors will fix the issue, sometimes "tightening" the connector is needed, and frequently several strands of the balance lead are broken at the connector resulting in big voltage drop when balancing current is flowing. A little observance / maintenance here will result in longer batt life.



bem -> RE: Batteries running-in and swollen batteries (9/16/2012 7:53 PM)

Hi,

Last summer I bought 3 pack of 6 cell DesirePower V8 35C 5200 mAh. Mid quality/price batteries. I have really tried to "nurse" them according to all LiPo take care of rules I know about. I started the first 10 flights with each pack to not run full power for only short times and I charged at 1C also the first 10 charges of each pack. Then I started to use 2C charging and that is what I use basically all the time, at home and at the field. I have never ran then below 20% capacity left (I have been very careful with that). Always storage charged to 60% capacity when I know I was not going to use the LiPo packs next day. I always balance charge.

How long did my LiPo last with good performance and not swollen?

Well during 1 years of use I managed to get about 200 cycles out of each pack before they started to loose punch and they have also swollen some now. They had difficulty to be balanced also at the end  near 200 cycles (took rather long time before the cells was at 4.20 volt/cell at end of charging). I bought a new 6 cell LiPo (another brand) and it is rather big difference in performance between the older packs and this new pack.

I had hoped the 3 LiPo packs would have lasted little longer, perhaps 300 cycles and I would have been very satisfied. But I think it is OK with 200 cycles but if I bought a high end very expensive pack like ThunderPower 45C or 65C then I think I would expect about 300 cycles.
I have used my 6 cell packs in an F3A traning plane (Sebart Wind S 50E).
I use charger Hyperion EOS 0720i Super DUO3 that has worked very well for a year now (my old charger of another brand went up in smoke a year ago).

For the future I hope LiPo batteries pehaps can be slightly lighter even if higher C like 45-65C and I hope for more cycles (I dream of LiPo that can cope with about 500 cycles but I do not know if that will ever happen).
The Lipo brands I have tried (Hyperion, ThunderPower, DesirePower and one Turnigy) has been very good performance so that I'm very pleased with.

/Bo



wagen017 -> RE: Batteries running-in and swollen batteries (9/16/2012 8:08 PM)

Anybody with long time experience charging at 5 C by now? I have one Thunderpower 4400mAh G6 ProLite 25C pack with 120 cycles which seems to be holding up well until now.

Volkert

EDIT: this is btw what is found at the TP website on running in new packs:
First few Flights
Thunder Power recommends no more than 3-5C average discharge for breaking in new packs. Also be extremely careful not to over discharge new packs (Packs should NEVER be over discharged at any time, but over discharging on the first flight will ruin the battery permanently before you are able to enjoy it.



ytell -> RE: Batteries running-in and swollen batteries (9/17/2012 8:21 AM)

"..Thunder Power recommends no more than 3-5C average discharge for breaking in new packs.."

This is 15-25 Amps for 5000 pack, which is too low even for takeoff. Meaning you need to put it on stand for the proccess. How many cycles are needed for a complete break in according to Thunder Power?





wagen017 -> RE: Batteries running-in and swollen batteries (9/17/2012 8:37 AM)

Don't know, and I also wonder about the statement. Is it really about running in of packs or more of a safety approach where you observe if packs are stable?

Volkert



serious power -> RE: Batteries running-in and swollen batteries (9/17/2012 11:02 AM)


quote:

ORIGINAL: wagen017

Don't know, and I also wonder about the statement. Is it really about running in of packs or more of a safety approach where you observe if packs are stable?

Volkert


Hi Volkert,
I don't really know much about the internal workings of lipos or what is going on with them when new.
I do know that there is something that happens in the first runs.
When they are new (and it seems lying up for a while) they are a little dead/down on performance.
They definitely improve with running - they seem to 'break in'.
I have not measured this improvement but I would say they peak at 10 to 15 flights in.
It stands to reason so that if they are 'stiff' when new they would heat more easily if pushed hard thus causing harm.
The problem is that this harm does not show immediately. It will result in poor performance later on in the packs life and thus is difficult to relate to the initial runs.

Brian



wagen017 -> RE: Batteries running-in and swollen batteries (9/17/2012 11:45 AM)


quote:

ORIGINAL: serious power


quote:

ORIGINAL: wagen017

Don't know, and I also wonder about the statement. Is it really about running in of packs or more of a safety approach where you observe if packs are stable?

Volkert


Hi Volkert,
I don't really know much about the internal workings of lipos or what is going on with them when new.
I do know that there is something that happens in the first runs.
When they are new (and it seems lying up for a while) they are a little dead/down on performance.
They definitely improve with running - they seem to 'break in'.
I have not measured this improvement but I would say they peak at 10 to 15 flights in.
It stands to reason so that if they are 'stiff' when new they would heat more easily if pushed hard thus causing harm.
The problem is that this harm does not show immediately. It will result in poor performance later on in the packs life and thus is difficult to relate to the initial runs.

Brian


That is an excellent point Brian and I agree with you, there seems to be a breaking-in happening. I for one have not have had compelling evidence from my own experience which suggests what would be the best way to achieve this break in. "normal operation" flying F3A to does not look to be pushing the batteries to the max. We typically don't use more then 15C max so normal flying might be a good breaking in process.

Volkert



Brenner -> RE: Batteries running-in and swollen batteries (9/26/2012 5:25 PM)

I used to break in all of my packs as per the various manufacturer's recomendations, but at a contest earlier this year I puffed a pack and the only packs that had to replace it were brand new, so I used them without breaking them in, thinking that I was sacrificing the long term life of the packs. However, these packs ended up giving more cycles than any of the packs that I had carefully broken in.

Initially I thought it was a fluke, so I used another set of packs without breaking them in, and I got the same long life performance. The original packs are still around with something like 200 flights on them. They are slightly puffed, but all of the cells still hold voltage well, and still have low resistance. The only effect of age that I can see is that now I can't take more than 3800mah out of them. (5000mah packs..)

I know this is just anecdotal evidence, but I'm thinking that maybe the newer high C rated packs aren't nearly as stressed as older, lower C rated packs were, and running them with a consistent duty cycle right from the start is beneficial for them. Regardless though, I no longer break in my packs.

Brenner ...

PS-> By the way, I also charge everything at 5C as well. No problems so far...



wagen017 -> RE: Batteries running-in and swollen batteries (9/26/2012 11:36 PM)

The loss of capacity is familiar. My (never broken in properly) Rhino 4900 packs reached well over 250 cycles, maintained Ir and C-rating but had about 4400 mAh left when I gave them away. They are still flying well.

Volkert



nonstoprc -> RE: Batteries running-in and swollen batteries (9/27/2012 2:15 AM)

I found that the true killer of a pack is to discharge it at or beyond its max. discharge rate for a relatively long period of time.

If the pack puffs up badly and is quite hot after a flight, the damage is done.



serious power -> RE: Batteries running-in and swollen batteries (9/27/2012 11:12 AM)

Hi,
For the last 3 or so years most brands are giving more cycles.
As a result we are generally happy with them ,if for no other reason than they were better than the previous lot.
One thing that I have noticed (I don't get through that many packs anyway) is that it is just one or two cells that let a pack down.
I would say that this is the case in 75% of cases - small sample though.
Anyway,picking up on Brenner's point, new packs are generally better than their predecessors and as a result it is easy to conclude that they are doing well regardless of treatment.
So it is difficult to know what is best. Would the pack with 200 cycles have done 250 ??
There is no doubt that over-discharge by rate (difficult for us) or by volume is the big no-no.

Brian



OhD -> RE: Batteries running-in and swollen batteries (9/27/2012 11:06 PM)


quote:

ORIGINAL: serious power

Hi,
For the last 3 or so years most brands are giving more cycles.
As a result we are generally happy with them ,if for no other reason than they were better than the previous lot.
One thing that I have noticed (I don't get through that many packs anyway) is that it is just one or two cells that let a pack down.
I would say that this is the case in 75% of cases - small sample though.

Brian


I agree. It would be nice if it were easy to replace a single cell but it would make the packs heavier and more folks would burn down their garages in the process.

Jim O



nonstoprc -> RE: Batteries running-in and swollen batteries (9/28/2012 2:58 AM)

If the bad cell is one of the outer cells, the replacemt is relatively simple. Otherwise, it is more involving.

Here are some obstacles to replace a cell.
1. The two tabs of a cell is soldered on to the PCB with lots of solder. A big iron is needed to heat it up for solder removal.
2. Cells can be damaged if too much heat is applied. The choice of a proper sized iron and the desoldering/soldering technique is criticle.
3. Possible of shorting a cell.

The saving probably is not that great, if the rest of the cells are near the end of life cycle.

I definitely not recommend going this route.



najary -> RE: Batteries running-in and swollen batteries (10/11/2012 5:42 PM)


Hi All,

I sent my questions to John Grzan from LEO Energy Pte Ltd the manufacturer of the Cellpro 10xp.

Here are his answers:

What do we know about battery running-in?
Is it really necessary at all? Not required

I know what running-in does for I.C. engine, but what does it do for battery? Nothing

Up till now, according to the battery distributors recommendations, I used to fly a new battery 5 times with not more power than half throttle. Yah they are distributors……not manufacturers like us

This is an unpleasant process; especially if you don't understand why it is needed and what it does to the battery.

Lately a friend of mine told me that his friend, someone who works in the U.A.V. industries, told him that that type of running-in (fly 5 times with not more power then half throttle) does not do any good for the battery. True and agree

He claims that a real running-in process is: charge the battery at about 0.5 C and discharge it at about 0.2 C, 5 times.

My friend told me that since he started to run-in his batteries this way, his batteries do not become swollen during the time.

I think that you have the best knowledge about my questions.
Can you answer my questions? Yes, glad to help

Can I use my Cellpro 10xp charger to run-in new batteries? You can use any of our chargers and our batteries too but you don’t need to run in.

If the answer is yes, I think it will be a good idea to upgrade the Cellpro 10xp software by adding a new preset function: Run-in, Have you consider that?
Yah nice idea if it were true

I know that during the first few cycles of a new battery the internal resistant of the Lipo cells going down and start to match each other, as a professional, can you explain me way that happened and what is the chemical process that is happening inside the cells during that period?
As a professional I never heard of such a thing. Why would they start to match each other?

If some thing is happening during the first few cycles of a new battery does it meter what is the current consumption strength during that period and why?No answer.

Best regards,

Isaac Najary



wagen017 -> RE: Batteries running-in and swollen batteries (10/11/2012 8:20 PM)

The more I think of it, the more I am convinced the only true denominator of pack life is initial quality. The only exception being maybe if you store packs a longer time (> 4 weeks?) at 4.2 volts.

Volkert



gaRCfield -> RE: Batteries running-in and swollen batteries (10/13/2012 2:03 AM)

This is from Wikipedia:

quote:

The overall reaction has its limits. Overdischarge supersaturates lithium cobalt oxide, leading to the production of lithium oxide,[36] possibly by the following irreversible reaction...


Seems to me that it could be possible to have local supersaturation with a high initial discharge rate - I have heard of 'forming charge' - maybe that is setting up the anode/cathode chemicals so they saturate evenly?

quote:

Unfortunately, organic solvents easily decompose on anodes during charging. However, when appropriate organic solvents are used as the electrolyte, the solvent decomposes on initial charging and forms a solid layer called the solid electrolyte interphase (SEI),[41] which is electrically insulating yet provides sufficient ionic conductivity. The interphase prevents decomposition of the electrolyte after the second charge


Similarly, the lithium batteries are relying on chemical changes within the cells. I would believe that a rapid discharge could be harmful if this initial chemical 'shield' was not fully developed on the first charge, or the first 5 charges, and thus would prefer a few break-in cycles to complete the necessary reactions.

I take Wikipedia with a grain of salt. However, chemical reactions to take time, and I could easily believe that the necessary chemical changes in a lithium battery are not fully developed after the first cycle.



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