Hello!
I have been using wallbuys as my battery dealer, because they are the only shop that ships free, and have low prices. In december, I puschased a pair of 18650b unprotected panasonics, and their date code showed 2013 january. I sold them, so didn’t have the chance to test. I recently got the christmas 50% off 18650b protecteds, and they are also made in 2013 January. The first cycle showed 3000mAh capacity, idk if it is due to the age, or it has to be broken in, but 3000mAh seems a way less than I expected. Have you also came across these old batteries from WB?
…
Post inadvertently lost :zipper_mouth_face:
…
I discharged it with a Convoy C8 until the low voltage protection started flashing. Then a fully recharged it with hobby charger. It showed 3028mAh.
The charge was done at room temperature.
They came at 3.62V, how much total capacity loss should I expect within a year of storage?
Not sure why you discharged it with the C8, since you have a hobby charger.
Also it is the discharging of the battery from full that gives you the capacity not charging.
Also it matters how low you discharge the battery to. For example, there will be a difference between discharging your battery from 4.2V to 3.0V as opposed to 4.2V to 2.5V. The later will obviously show more capacity. Otherwise you're not comparing oranges to oranges but oranges to apples.
Perfectly good battery…
discharge that battery until protection kicks in at 2.5V and then charge it with the hobby charger and let us know what resultes did you get… Until then you can add question mark at the end of your title…
Which hobby charger? Capacity measured during charging isn’t that accurate. Use the discharge / capacity function. Need to know the discharge current & what voltage it stops discharging at so you can compare it to HKJ’s tests.
Capacity loss with a year of storage depends on the temperature (& voltage) its stored at. BatteryUniversity How to Store Batteries When new batteries are manufactured they are not fully charged to reduce capacity loss.
Well siletto at least you receive your batteries. I ordered 4 pairs of batteries from WB in 13 December 2013 but still have not received them yet.
3000mAh is a normal discharge value for ncrbs.
I also get this discharged to 3.1V.
All ncrbs I got from wallbuys so far were excellent.
I finally tested the battery, discharged it too 2.8V, and then recharged. The capacity now is 3260mAh. My hobby charger is the Imax B6 (the copy ebay version not the genuine), so it might not be very accurate
Do you know what current its discharging at?
3260mAh would be just about perfect if its at 0.5A / 500mA.
HKJ Test / Review: Panasonic NCR18650B 3400mAh (Green) (discharged to 2.8v).
Have you checked the Voltage Reading of the IMAX while discharging?
Just measure the voltage on the cell with a DMM and compare it to the displayed value.
One of my most used cradles has due to its resistance a failure of 0.1V@1A.
This. Remember, V.IMAX = V.Batt + V.wires + V.cradle(spring and all).
I soldered two 14gauge wire from my Imax PCB straight to my battery holder for this exact reason. Somehow, my overall battery capacities have increased “magically”. 
This must be my problem also.
Even if i adjusted the IMAX as low as possible, it is still overmeasure voltage during charge. It is accurate in the calibration menu, but overread during charge.
I charged and then discharged the same cell @ 0.2A. It gave 3240mAh and another 90 if i use the 0.1A discharge. I believe it must be the charger, i’ll change wires thicker.
Just some helpful tips about using your charger- The voltage displayed on the charger during charge on my 4-button hobby charger is the voltage being delivered out of the device to the cell to maintain a chosen current. Once it hits the target voltage or CV phase the current drops slowly until the cell is full. If it is calibrated correctly then the voltage readout on the screen should be the same as if you measure the charging leads during charging. The actual voltage of the cell will be lower f you stop the charging process and then measure cell voltage.
To measure the capacity of a cell, fully charge it and then do a discharge cycle and that data output is your capacity. Capacity reported during charging = capacity into cell + energy lost to heat + resistance + etc… and is not as accurate of how your cell will perform. And the rate at which it will discharged will almost always effect how much capacity the cell has. More current leads to more energy lost as heat due to internal cell impedance. You can see this on any of HKJ’s cell tests. The amount of fluctuation between cells will vary by their design and quality. Here’s also a link for more about your hobby charger.
Thanks for the great explanation Hbomb. That really puts it all into perspective.
I finally just received 4 NCR18650B Unprotected cells purchased a long time ago. They all came in at 3.65v’s, and appear to be of new stock. I am not sure how to read the Panasonic codes. They took a while, but eventually came in.