Recent content by mighty82

This is very nice results. I like the internal resistance staying at a low level. In my experience IR seems to become a problem before capacity loss. Had this problem especially with nca cells.

Found the problem. Battery negative balance lead had broken.

nBG5qz9Wm_s What's going on here? Cell group 1 is jumping up and down and it's going in and out of high and low voltage protection mode. I ripped the battery open to check the actual voltage of cell group 1, and it's at 4.1V thankfully. This is a little scary.

Strange that all reputable sellers lists vtc6 as a nmc cell. In fact the study you are pointing to is the only result I can get from searching vtc6 plus nca. It just goes to show one can't be sure about anything. It was my understanding that nca was not ideal for high discharge cells.

I think he referred to the 3 cells in the study I linked to. In the study all 3 cell types lost about 3% in 10 months at room temperature under 60% soc. So it's not too far off their results.

You are right about the comparison of course. Although I recognise the trend of nmc cells having less rise in IR etc. They have some basic differences in chemical buildup. But then again, some HE cells show even worse cycle life than mentioned HP cells, like panasonic PF and sanyo/panasonic GA.

VTC6 is definitely NMC, I don't think the LG cells are NCA either.

That's a fairly rapid decline. In many applications, calender ageing will render it useless before cycle wear. That might be why tesla is sticking strictly with NCA chemistry for electric vehicles? NCA has always been touted to have superior calendar life. According to this study the...

Vtc6 seems like one of the very best cell to consider for high amp applications. You really can get both high power and high energy these days. What's the drawback? From what I can see from my own experience and what I can read online, calender degradation only seem to be a problem if stored...

Cool! Will you sell me your testing equipment for cheap then? Since you won't be needing it anymore I mean :wink: Sad to loose you as a resource though. Your work is really interesting. I'm sure a lot of people would chip in a few $ for your work if you had some sort of donation thing going...

Any idea why the cells have lost more capacity percentage wise inside the cycling interval than total capacity degradation? Have you tried retesting the cells with the previous parameters after it has been fully cycled to see if some of the capacity within the cycling interval has been regained...

Sharing ideas for future tests is not being entitled. I'm sure he's going to continue testing cells in the future anyway. The effort put in here as well as the execution is amazing, and I am very grateful for it! Having this many different cells tested at the same time is gold. Comparing cells...

I would also like to see at least some of the cells tested at 4.2v. With this much great information it is a golden opportunity to see what difference 4.1v vs 4.2v actually makes with the other parameters being the same.

What happened to the chart? I get this error: "The selected attachment does not exist anymore"

Okay. I don't give my batteries enough cycles to cause a lot of capacity loss either. But I have noticed increased IR with resulting voltage sag after a few years. Also when removing cells from old laptop batteries etc they are ofte close to their rated capacity but with very high ir. Could be...