I'd like to get idea on the best way or process to check the capacity, resistance and usable condition of used 18650 batteries ?
I plan on buying several hundreds of these batteries for an up coming project .
Thank you, Oscar.
I'd like to get idea on the best way or process to check the capacity, resistance and usable condition of used 18650 batteries ?
I plan on buying several hundreds of these batteries for an up coming project .
Thank you, Oscar.
Reliably determining the state of health of a lithium ion cell is pretty hard to do unless you have a reference cell. If time is not an issue and you have a source, a sink and a power meter available then you can cycle the cells as others have also suggested already. If you don't have this kind of equipment available then personally I think the cost required for testing in relation to the money you save by buying used cells is too high.
If you have reference points of your cell then a possible way to make a determination of the state of health are impedance measurements at different / specific frequencies. Here is an example how this looks like:
Suitable instruments for this measurement: HIOKI BT4560 or HIOKI IM3590. (but certainly not suitable instruments to measure a hundred of used cells unless you have one of these instruments available for free)
The same thing would apply for state of charge measurements - you won't need to measure the entire curve (basically you can ignore the large overlapping parts) but you need to have reference values of the exact cell type. Temperature has a big impact on the measurement, by the way.
Reliably determining the state of health of a lithium ion cell is pretty hard to do unless you have a reference cell. If time is not an issue and you have a source, a sink and a power meter available then you can cycle the cells as others have also suggested already. If you don't have this kind of equipment available then personally I think the cost required for testing in relation to the money you save by buying used cells is too high.
If you have reference points of your cell then a possible way to make a determination of the state of health are impedance measurements at different / specific frequencies. Here is an example how this looks like:
Suitable instruments for this measurement: HIOKI BT4560 or HIOKI IM3590. (but certainly not suitable instruments to measure a hundred of used cells unless you have one of these instruments available for free)
The same thing would apply for state of charge measurements - you won't need to measure the entire curve (basically you can ignore the large overlapping parts) but you need to have reference values of the exact cell type. Temperature has a big impact on the measurement, by the way.
