THAT'S BS...
one of a lipo's well renouned features is the ability to sit fully charged for weeks on end and still be ready to go!!

nimh's cant do that nor can nicd's....but lipo's can hold their charge for years on end, but anything more than a month would be a little silly IMO.

There is a blurb at batteryuniversity that says keeping lipos at elevated voltages promotes cell corrosion on one of the plates. It was actually for Li-Ion, but the technology is similar. If I'm not running them for a week or more, I keep them at around 3.8v/cell, which is between 1/2 and 3/4 charge. I figure at worst, I have to charge them a little while the night before to top them off.

But having them puff after on;y a night or two at full charge? I'm gonna call shennigans on that one. Chances are, they were just overdischarged despite whatever their labels say.

Negative, didn't see any reason too

It is well documented that storing packs at full charge will increase the internal resistance and decrease the capacity of the pack. Kokam had some white papers on this floating around the internet years ago, but I cannot find the link right now. I believe they said that storage was anything over 24 hours. This is why most newer chargers have a "storage" or "50%" charge/discharge setting, and when you buy packs they are generally around 3.85 V/cell. This is considered the "optimal" storage voltage. In Kokams paper temperature also played a big roll in loss of capacity. Storing your packs around 45*F will also increase the life of a pack. Placing your pack in a ziploc bag and putting it in the refrigerator works fine, as long as the pack does not freeze, or get below 32*F.

Whether sitting at full charge will cause a pack to puff or not has not been well documented, as far as I know. I do have a few packs that have puffed from sitting fully charged from my early lipo days (Around 2005) when I did not know any better. These packs that puffed are from various "high end" and "low end" companies. Right now I have approximately a dozen companies, and over 100 packs. They are used in all types of RC and also non-RC applications. I also still use some of the packs from those early days for low draw applications, such as receiver packs.

Now cell chemistry does have everything to do with capacity, cycle life, discharge capacity, and puffing. Let me start by saying I am not trying to put SMC down in any way, but SMC seems to be having some problems with their newer cells. I have some of their older packs that perform very well. But I have seen lots of their pack either puff or have other problems with a relatively low number of cycles lately. I work at a LHS and we do sell SMC, Thunder Power, Hyperion, Dynamite, Orion, Venom and other packs, so between my own packs and packs we sell, I do get to see how all the packs perform.

SORRY for the long post and rambling post, but I do feel that there is many things that can be done to maximize the life of lipos. And I do feel that SMC may be right in saying that storing their pack even for short times at full can cause them to puff due to the chemistry of their cells. It could also be from many other factors, temperature, over-discharge even though your cutoff is set at 3.5 V/cell. Just a note, I have some TP 40C packs that need a LVC of 3.6-3.7 V/cell just to keep the discharge limited to about 80%.

Again sorry for the long and rambling post, but I'm just trying to put some of the things I've learned about lipos over the years to good use. If I find time over the next few days I may write a nice long and detailed post about lipos since I see soo many questions about them on here, and every other forum.

Another thing is maybe don't charge to exactly 4.2v/cell. I set my CC/CV threshold on my charger to 4.15v/cell. You lose very little runtime but that extra 0.05v/cell gives you a little wiggle room in case the balance is not perfect. That way, there is less of a chance for a cell to exceed 4.2v by the end of the charge.

I've been storing a few of lipo packs I don't use anymore fully charged for a few years now just to see if this claim is correct. Well, none has puffed and I even charged a couple and ran them. Well, they still performed the same way they did before I stored them. A couple of the packs doesn't have balancing wires on them and no problem at all. I hardly balance any of my packs and none have shown any sign of puffing. Now one pack that I don't use anymore is composed of many cells and that packs has been stored fully charged for almost 3yrs now. I only check the voltage to see how far it has drained and it is at 12.3v, not bad when fully charged is was 12.6v.

So...... what the conclusion you can come to in this situation with SMC's and their claims in regarding how to properly care for their Lipo's vs other manufacturers?

Wouldn't that be made irrelavent if your balancing your lipos on every charge like I do? My Triton2 charges via the amount of maH the battery is designed to hold, not voltage other then the default 7.2v lipo cell setting which tells it was size of Lipo im using. This however doesn't limit my charges via voltage, just mAh, at least thats what the Triton2 goes by, is probably different for every charger and i've never seen my cells go beyond 4.2v or 8.4v once its completed charging. By changing my MMM LVC to 3.5v, ive been leaving the lipo's around 800mah left in capacity ass soon ast the LVC kicks on. Which is a little bit more then the default Lipo 80/20 rule, but I have better things to do then carry a freaking timer on me when im bashing and having fun

Somewhat. I balance charge as well, but if there is a situation where the balancer cannot equalize the cells before the CC/CV threshold, one or more cells could go over the 4.2v limit. Of course, this only applies to non-balancing chargers.

I'm not sure how the Triton works internally, but most chargers apply a CC charge until the voltage hits 4.2v/cell, then switches to CV mode and the current dwindles down to a set value before it shuts off. Actually, to be accurate, most chargers are always doing a CC charge, but at the "CV" phase, they just monitor the voltage and make constant changes to the charge current. But that's just a technicality.

As far as the LVC point goes, I take it case by case. I like to see 3.5-3.6v/cell open-circuit voltage once the load is removed for about 10-15 minutes. All batteries will exhibit some voltage "drift" back up once you remove the load. How much they drift back up depends on their design. Cells with higher resistances will drop voltage under load more, and will drift back up more, so I set the LVC for 3.2v/cell. If you have a cell with extremely low resistance, there is much less drift once the load is removed. So, to get a decent resting voltage, the LVC needs to be set higher to compensate. The same approximate mAh is used, it's just a matter of understanding how batteries work and tailoring care and maintenance accordingly.

The only pack I have every puffed was a MA pack, but no surprise there. It was being used in a setup that it should easily have handled. Oh yeah, I did puff another higher quality pack, but that was because it was a 2p pack and one of the cell pairs came apart causing one cell to handle the entire load.

Funny thing is alot, if not the majority of plane and heli guys do exactly that... :/

Well with them I could see why, if their battery goes to low, down goes their plane/heli. If I run out of power, I coast to a stop

Most lipos will fail first from over rated specs, not being built correctly, using them in really cold weather and people just pushing them to their limits. Storing care should be mainly what works for you. Some people will store their lipos in a cool place and it seems to work for them. I just store them in my basement inside a few ceramic pots. I charge them and store over the winter. I charge them before I use them and I've been doing it like that for a while. The only lipos I had that actually scared the crap out of me was my 2 3S Max Amps packs. The problem that we see now is that people will always look at the higher number before questioning where the cells came from and if they're really capable of delivering 30, 35, 40, 45, 50 or 60C. I would like to see them get some sort of data from their sponsored racers to get a base level of an avg. AMP usage at race pace and take that data and cycle their cells/packs at that level and above to see how well it will do. Afterwards rate the pack properly. An example would be: Our pack will deliver 300 cycles at 50A avg. with X amount of % (capacity) left after 300 cycles or our pack will deliver 500 cycles at 35A avg. with X amount of % (capacity) left after 500 cycle and they can even try out X amount of burst amps from data recorded through out a race and give an X amount of time a pack would provide the bursts. Anything above what ever they claim would be up to the user. Yes, it takes time to get a number system going, but a better one would come out of it.

Uhh, cliff notes version of that? :mdr:

EDIT: WEDNESDAY FOLLOW UP

I decided to give Bryan at SMC another today and verify some information about their SMC Lipos, specifically what the safest route is to keep them in a charged and discharged state:

Me: Yes, is this Bryan?
Bryan: Yes it is
Me: Bryan this is Freezebyte again from Montana
Bryan: Hey Freeze, good to hear from you again, what can I do for ya?
Me: Well, I'm calling to give you and update on the condition of my Lipo after I discharged them and left around 1000mAh inside them which put them at around 7.3v. The puffing seem to have gone down a little bit.
Bryan: Ok, you should be in the clear then, the new Lipo cell chemistry is a bit more forgiving then the older batch, so just keep an eye on it.
Me: Sounds good which brings me to my follow up question that I couldn't remember your full answer to. For your guy's SMC Lipos and cells inside them, what is the maximum and safest amount of time to keep them at a fully charge state that won't damage the cells?
Bryan: For our Lipo's, no more then 1 day, 24 hours max. Past that, you greatly increase the risk of causing the chemicals inside our cells to start to break down and risk puffing. I know it sucks, I know its a bit inconvienent for some people but our Lipo's are designed for performance and racing and arn't as forgiving as other "generic" Lipo's. Theres a tradeoff, you either want really good performance Lipo's that require more attention and care or you can have lesser performance but be able to beat the crap out the Lipo for extended periods of time. Its like a Ford Focus ya know, its built to last and go for miles and miles but it sure as hell ain't gonna win you any street races vs a Ferrari. Each one is built for a different reason and use.
Me: Well, that makes perfect sense, I didn't think about that
Bryan: Yeah, the cells we use in our Lipo's are designed to give maximum punch and power for racing needs and that comes at a price, in this case, they require more attention to their charged and discharged state and react poorly when you over or under discharge them vs other Lipos. I know at one race one of the guys their was using Orion packs and was doing pretty good but was having issues over some bigger jumps. He asked if he could borrow one of ours and he was able to clear the jumps no problem now. I"m not saying Orions are crap, they do make good stuff, but I don't think they are geared for real high end demands like our packs are designed for, however the tradeoff is that you can beat, abuse and use them over and over and they just keep taking it. It just a matter of what you want out of the Lipo.
Me: Yeah, i've heard peeps saying that their Turnigys and Zippys are sitting charged for days or weeks on end with no ill effect and last a bit longer
Bryan: Yeah, Orions are apparently the same way, but we've also seen the performance difference between their packs and ours on the track so its either babying a high performance pack more or be able to hammer and beat up a pack but have less performance, you can't have both.
Me: Well, that makes alot of sense now that you put it that way. I"m glad I asked and now know how to properly care for your guy's particular Lipo's and cells. Thanks so much again Bryan, I really appreciate it
Bryan: Hey your most welcome, glad to be of help. Give us a call if you have any other questions or concerns, thats what were hear for. Oh and congrads on your truck in the new RC Car action! Sweet looking color scheme, simple but nicely laid out with the wheels and tires and even nicer scenery and bashing spot, im jealous!
Me: Lol, well thanks so much! I am pretty proud of it myself and I just heard that my truck also made RC Driver in the Jan 2010 issue!
Bryan: Really? We'll congrads again, I'll keep my eye out for that one too! I'd kill to have a bashing spot like you have up there, especially with that scenery!
Me: Ironic, you want my bashing spot, and I want your guys big races and events, lol Thanks again Bryan, take care!
Bryan: You too freeze!

So there ya have it folks, straight from the horses mouth. Needless to say, i've decided I want more "bulletproof and forgiving" Lipos for my needs. I hate babying crap as it doesn't make this hobby fun when I have to spend extra time and effort into something as simple as a battery. Im gonna order some Turnigys when my SMC's give out and take this as another valuable lesson learned in the new world of Lipo and RC usage.

Hmm. Maybe so, maybe its complete bullshido. I don't own them, so IDK.

Either way sounds like a giant pain in the ass and terrible for a bashing rig. G/l w/ the Turnigys