Originally Posted by
Roelof
I would love to see a manufacturer code of the cells on the case. Like with CDR and DVDR there are only a few manufacturers and many brands. The Media code on the disk is referring to the original manufacturer with which a true list of quality can be made.
With LiPo's you buy a box with a nice RC brand label on it but no info of what is placed inside so today it can be "cheese" and tomorrow it can be "pinut butter". (in a way of saying)
Also there can be a difference if the battery comes directly from production of was just waiting 6 months in a warehouse for a buyer.
While I find that an intriguing idea, Im not sure it would be of much use since the same manufacturer may make cells for 20 different battery companies but those cells can all be made to differing specs for each company so there still wouldnt necessarily be any consistency there unless the manufacturing code also had stats about the cells specific specs also. Battery companies generally order cells with certain specifications so unless a brand changes their specs on their cell orders the cells of a particular brand and model of battery should be roughly the same. Im actually starting to test multiples of the same packs in order to make sure that is indeed the case. Its a bit early in to that aspect of my testing to speak definitively but so far what Im seeing supports that statement.
Originally Posted by
Alexv2024
This isnt related to the big battery thread on RCgroups is it? Doesnt look like it. But if you haven't seen it, also an interesting read.
It is not related but Ive been aware of his work for a long time. His work focuses on EDFs though and Im mostly only in to ground kits so I thought Id do some testing of my own
Originally Posted by
lexusbest
Thanks for sharing! Awesome job
Thanks, I hope it helps
Originally Posted by
billdelong
I used to make discharge graphs as well, but what I found was that over time almost all brands of batteries were comparable to an extent where I later discovered that IR was more valuable in detecting battery health and performance so I stopped making discharge graphs. Here's an example of a graph where age of pack makes a significant difference in the readings:
I agree that IR is very important which is why my testing encompasses not only mAh and Voltage under load but IRs as well.
Originally Posted by
billdelong
Before I stopped making graphs I made sure packs were fairly close to new and would compare to older data when I bought a new pack to see how it compered to other brands when they were new, ultimately the rA was fairly uniform across all the brands I tested at the time and that proved to be worthy enough to the point in stock racing where 100C packs became a law of diminishing return and IR was the only thing that mattered and why I only charge at 40A to this day:
Could you explain a bit more here? Im not sure I understand what you are saying exactly. Im also not familiar with the rA nomenclature. All of the packs I test are brand new and Ive recently started testing identical packs to make sure that results for a given brand/model of LiPo are within a certain tolerance. So far the duplicates have been very very similar to the original packs. Please expand on the diminishing returns and why you only charge at 40A now. Im intrigued.