Battery wrapping companies are switching from rewrapping “OEM” cells from Samsung, Sony, etc., to cells manufactured in China because of the more consistent supply available from the China factories. They don’t have to scramble everywhere looking for excess inventory being sold here and there. There can be a monetary incentive to do this too.
That is a real concern for us! We are often using these cells without any idea whether they have passed the most basic safety testing or even what battery chemistry they use. While I don’t think they use the same chemistry as LiPo’s, I want to be sure.
These China manufactured cells also have a lot more variation in their performance from cell to cell than those from Samsung, Sony, etc.
I am tired of our community being guinea pigs for inconsistent cells with unknown safety. All cells not in original OEM wraps will now need datasheets and all China manufactured (or unknown) cells will need a complete datasheet, SDS (safety data sheet), and a UN38.3 safety test report sent to me as part of my testing. This is not an unreasonable request. The SDS and the very basic UN38.3 safety testing are required to ship the cells out of China.
I am also tired of these companies using my testing to set ratings. Submitting a datasheet before my testing starts helps a bit to ensure that they won’t just toss a number onto the wraps for now, wait for my test results, and then create new wraps with my rating on them. They will have to determine the rating in advance on their own.
A missing datasheet for a rewrapped OEM cell means a lowering of the current rating to a point that will result in a 10°C drop in cell temperature when discharged continuously at its original rating and a 10% reduction of the capacity rating. This done because I can’t guarantee that I have identified what cell they are rewrapping and we don’t know what grade cells they are using or might switch to in the future.
A missing datasheet or safety test document for a China manufactured cell, or unidentified OEM cell, results in a Do Not buy recommendation. This is done because without the documentation we don’t know how risky it is to use them. The cell will also be tagged in the table as missing documentation.
If any company submits falsified documents all cells of theirs will be permanently tagged as Do Not buy.
If any battery wrapping company changes a cell without an obvious wrap change then the cell is given a Do Not buy recommendation and is not retested. I am not wasting any more time on this kind of stuff.
Eventually submitting the datasheet and/or safety documentation means the full ratings are restored. I might retest the cell before doing this though and the company will just have to wait for that to happen.
This thing has been a monster to research and implement and it is all a work in progress. Anything is subject to change at any time but I hope not as it will already be disruptive enough as is.
I suspect that almost all of the China cells and many rewraps too will end up being derated or tagged Do Not Buy, at least for a while. But this only reflects what we’re dealing with now. We are using cells without any knowledge of whether they have passed even the most basic safety tests.
I want to sincerely thank Assi Rutzki from Enerdan and Jonathan Tang from NPE (two distributors) who have been a huge help in sorting out the dizzying array of international lithium-ion safety regulations/standards and documentation requirements. Without their help I would still be floundering in a sea of incredibly confusing paperwork!
I’ll post more detailed information about all this soon and will do a video too when the new tables are posted.
That is a real concern for us! We are often using these cells without any idea whether they have passed the most basic safety testing or even what battery chemistry they use. While I don’t think they use the same chemistry as LiPo’s, I want to be sure.
These China manufactured cells also have a lot more variation in their performance from cell to cell than those from Samsung, Sony, etc.
I am tired of our community being guinea pigs for inconsistent cells with unknown safety. All cells not in original OEM wraps will now need datasheets and all China manufactured (or unknown) cells will need a complete datasheet, SDS (safety data sheet), and a UN38.3 safety test report sent to me as part of my testing. This is not an unreasonable request. The SDS and the very basic UN38.3 safety testing are required to ship the cells out of China.
I am also tired of these companies using my testing to set ratings. Submitting a datasheet before my testing starts helps a bit to ensure that they won’t just toss a number onto the wraps for now, wait for my test results, and then create new wraps with my rating on them. They will have to determine the rating in advance on their own.
A missing datasheet for a rewrapped OEM cell means a lowering of the current rating to a point that will result in a 10°C drop in cell temperature when discharged continuously at its original rating and a 10% reduction of the capacity rating. This done because I can’t guarantee that I have identified what cell they are rewrapping and we don’t know what grade cells they are using or might switch to in the future.
A missing datasheet or safety test document for a China manufactured cell, or unidentified OEM cell, results in a Do Not buy recommendation. This is done because without the documentation we don’t know how risky it is to use them. The cell will also be tagged in the table as missing documentation.
If any company submits falsified documents all cells of theirs will be permanently tagged as Do Not buy.
If any battery wrapping company changes a cell without an obvious wrap change then the cell is given a Do Not buy recommendation and is not retested. I am not wasting any more time on this kind of stuff.
Eventually submitting the datasheet and/or safety documentation means the full ratings are restored. I might retest the cell before doing this though and the company will just have to wait for that to happen.
This thing has been a monster to research and implement and it is all a work in progress. Anything is subject to change at any time but I hope not as it will already be disruptive enough as is.
I suspect that almost all of the China cells and many rewraps too will end up being derated or tagged Do Not Buy, at least for a while. But this only reflects what we’re dealing with now. We are using cells without any knowledge of whether they have passed even the most basic safety tests.
I want to sincerely thank Assi Rutzki from Enerdan and Jonathan Tang from NPE (two distributors) who have been a huge help in sorting out the dizzying array of international lithium-ion safety regulations/standards and documentation requirements. Without their help I would still be floundering in a sea of incredibly confusing paperwork!
I’ll post more detailed information about all this soon and will do a video too when the new tables are posted.
