Another Battery Storage Thread ...? Yes.

[flydiver]

Lipos self discharge slowly. If they do, they are no good.
A fully charged lipo left that way for a long time is highly likely to be a puffed or low performing battery. The higher-C/higher performance batteries seem to be more subject to prolonged full charge storage and do so more quickly.

Your experimentation has some validity...IF and ONLY IF, you could actually get your hands on the SAME battery when it came to replacement. That's essentially impossible as the battery will have 'moved on'. It may have the same LABEL, but it won't be the same battery. Major brands often change their source. Manufacturers are constantly changing their chemistry and methods. Sometimes they improve, occasionally they screw up. They it's pretty rare when they admit when they screwed up.

That's also the problem with opinions from a vast array of fliers. What 2 guys have bought having the same label may not be the same battery.
Now, assume they did get exactly the same battery at the same time.
If the one guy lives in a hot climate, keeps them charged all the time, and flies helis or ducted jets that guy is going to get totally different results from the same battery used by another guy in a cool climate, kept at storage charge between flights, and used in a low output plane. The first battery might last 20-30 charges. The 2nd battery might go 2-3 years and hundreds of charges. One guy will think the are crap, the other guy will think they are fine.

It is very difficult to do actual controlled experiments on lipos even if you think you are making a serious effort.

[hghost]

I am still in confusion mode with Lipo batteries.

I been checking them every so often and also experimenting with storage charge and full charge.

It being winter I can not fly so all i can do is bench test some.

Mind you as i said before, I have no clue about lipo batteries, and very little knowledge of Nimh batteries and even 12V car batteries over the years have changed since my days, they are confusing now to.

My Nimh batteries my RC Cars use, set at the cut off rate all winter.Come spring I charge them and use them and when not in use they set uncharged and work for years. Some every once in awhile hold less charge than others. It has always been that way even if set at storage charge. As you said fly, not every battery is the same.

Now with these Lipo's I been seeing if they drop while setting at normal room Temp (That room is far cooler than every other room in the house) I did not store them outside in the outbuildings as i planned. I wanted to keep watch on them and test them some. They are in Lipo safe bags and in Metal containers.

Some I allowed to stay fully charged for months...and they seem fine. I discharged them down and restored them to see what they do....At this moment i have no Fully charged batteries in my stock. Those little Chiklet type batteries I have are close to full charge but not all the way....wanted to see what they do...so far those stored at full charge has not seem to affect them in any manner thus far . So i discharged them a little and restored them to see how it affects them.

I am just doing this to see what they do and how they are affected for my own reasoning.

I was going to keep a log, but just decided to watch them and check them and see how they react.

I will know come spring.........for sure.

But as we talked about before everyone has a different opinion and everyone seems to treat them differently.

And many things play a factor on how the battery performs.

[flydiver]

You won't learn anything from passive tests. Voltage shows very little. They have to be put under a load appropriate for their intended use. That means minimally at least the draw you expect when flying WOT. If you don't have one yet, get a wattmeter and test them that way, on the plane under power. A good battery holds voltage under power. An unsatisfactory one sags voltage and performance is lackluster.

Addendum-knackered sailor just asked about C-rating. supercubclub.proboards.com/thread/5387/discharge-burst
I pointed him at a website that has a knowledgeable author. I suggest you read it and bookmark it.

In effect prolonged full charge storage increases the Internal Resistance of a lipo and lowers the C-rating. This effectively lowers the performance. The CAPACITY may still be there by not the amperage deliver support. Think of amperage as water delivered through a pipe. High performance batteries (high C-rating) have a large pipe and low resistance. As the resistance goes up (lower C-rating) the pipe gets smaller and the ability to deliver amperage is compromised.