Damnit, the Lipo battery industry needs better standards!

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.