camthecam said:
Hey, has anyone done a resistance check on Leaf cells and is it of any use for pre purchase?
Cheers in advance.
camthecam,
Any and all batteries have an IR. Now what is acceptable for each chemistry (Pb, NiCad, NiMH, etc) that I do not know.
Except I do know Li-ion especially 18650 cells. Generally speaking lower is better. The less internal resistance a battery has the faster it will charge and the better it will perform.
Now I am sure that a leaf cell has a manufacturer's spec for IR be nice to find out.
Pre purchase IR test........ Well yea. Would you by a horse without looking at its teeth? Of course if it is a gift horse....................
If I could have tested the IR of all the cell in the laptop batteries before I broke them apart I would have saved a ton of time while harvesting over 8000 (many of them never made it into the spreadsheet because of IR) cells and getting ~1200 usable cells with proper IR and SOH.
I now break packs apart check IR if cell is not acceptable I do not spend any more time on it.
Now mind you I kept the IR, mAh, and SOH in the packs I am building to a very close tolerance. By no means do I only have 1200 cells out of a recorded ~6000 that are good. There are a bunch of LG, Sony, BAK, etc. that have high IR from the get-go with a very good SOH. Those I will use for another purpose, just not in a Powerwall where I want the best matched cells I have.
So yea in a long winded roundabout answer to your question yes I would check IR and try to get the leaf cells with the lowest IR and try to match all of them as close as possible.
Wolf