Hi folks, I need some help with these batteries. I purchased a few from Ric at Cnquality goods. They reach full capacity on my Xtar WP2 at 4.2v.
I then purchased a few of the same batteries from BIC. When I put them on the same charger they reach full capacity at 4.17v.
All are protected cells. Does this mean the protection circuit on the BIC cells is cutting off too soon or does this mean that the BIC cells are not the same
quality as RIC's cells?
In any event, does the slightly lesser capacity really mean that much?
It won't be the protection circuitry as that won't cut until significantly above 4.2v (probably 4.35ish). Charging to a lower voltage doesn't necessarily mean lower capacity either. In a WP2 which uses CC/CV charging with a cut-off based on a min current taken by the cells it probably just means that the cells terminating at the lower voltage are slightly older and so have built up a little more internal resistance.
It isn't really anything to worry about, but interesting to note which dealers are carrying the latest batches of cells.
I have some laptop Panasonic CGR18650 harvests that "only" measure 4.17-.18V. But they hold a charge really well and will hold that voltage for several months (the longest I care to test them for LSD). Capacity testing measures anywhere from 2100-2300mah, at 1A, which is the limit for my charger. I use them all the time, they will deliver a healthy non-saggy current to my XML lights driven at 2.8-3.5A.
The reality is a new/healthy 18650 cell will only remain at 4.2V for the first 10-20 seconds when pushing an XML. Where it quickly drops to below 4V, and settles in around nominal 3.6V. I really don't think you are missing much of anything without that first .03 Volts. So long as the cell can hold a charge and possess sufficient capacity.
Curious... who is "BIC" ? Do they have any history of selling old/tired/used cells?
BIC is Buyincoins.com. I read on another post that people have had issues with cells purchased from them.
In this case, I figured these 3100mAh Panny cells have only been available for a few months so any I purchased would have to be new. Either I'm wrong about how long these cells have been around, or maybe BIC is selling used cells. Either way, they are not charging like new cells.
So, let this be a warning about buying cells from BIC
Do you have any way to charge or discharge test them for capacity? That does seem a little suspicious.
When I mentioned above I have some older cells that peak out at 4.17V-4.18V, I forgot to mention those are the worst (most suspect) ones of the lot. The better ones (and the majority) come off the charger at 4.19-4.20, and at that voltage they match my new/fresh 26650 LiNiCoMn cells.
Unfortunately, I do not have any test equipment for that. I paid $19.00 for 2 cells so I'm not going to worry too much about it. But, as another Poster said, it's good to know which Sellers are selling sub-par cells. I'm still not sure if this particular cell has been around long enough to deteriorate from age, so I'm guessing these are used cells.