KeepPower 18650

[jp_over]

Friends,

I need some battery matching / charging advice. Here's the setup:

- Charger: SkyRc Mc3000 set according to the manual for 18650s. Never had an issue before recently with several generations of 18650s; all purchased new.
- Batteries: 18650 KeepPower 3120mAh Sony US18650VTC6 Protected High Discharge Button Top P1831R (R Series)
- Application: Malkoff Hound Dog custom / 3 x 18650 used for brief periods nightly
- Charge frequency: Once every 2-5 days, never below 3.6 volts
- Battery Replacement Schedule: Annually or a little past this if the cells are performing well

Problem: The last batch of 3 new batteries (reputable supplier) had a bad cell which caused the light to shut down. I'm waiting on replacement of the bad cell but in the interim I ordered 4 new batteries and here are the results (attached).

A few possible causes from my novice experience:
1) I simply got a bad cell.
2) KeepPower quality control issues with recent production
3) Supplier quality control issues

Any advice or similar experiences with KeepPower 18650s? Do the charge results above look ok/matched?


Thanks,


JP

 

[aznsx]

I'm unfamiliar with this particular information display, so I'm not entirely comfortable with interpreting the displayed results (and I use the MC3000).

That said, it appears these cells were fully charged, and the 'capacity' number reflects the total charge required to bring them from whatever SOC (state of charge) they were in initially (unknown?) to a fully charged state. If so, I pay little or no attention to that measurement, as it doesn't really reflect what I'm interested in.

I evaluate cells based primarily on 2 measurements.
1) Discharge (not charge) capacity
2) Internal resistance (IR)

What stands out to me is the large difference in 'BatRes', assuming that means IR (internal resistance). This is normally measured with cells at full SOC, and the number increases as SOC decreases. If these cells are fully charged, and there's that large a difference in their IR, I don't understand that. If I fully charge 4 cells and their IR differs by that much, I would want to understand why. Since lower IR is generally better, I also don't understand why the cell you 'suspect' as possibly being problematic shows lower IR after charging (normally a good thing) than the cells you might be assuming to be the 'normal' ones.

So, while I'm somewhat concerned / confused by the numbers, it's the IR number that I'm focused on, rather than the 'charging capacity' you're focused on, and that's the number I question / don't understand.

As an example, when I tested the 16650s, note that one cell had higher IR when fully charged than the other 3, and this was also reflected by lower discharge capacity. That 'makes sense', and it's the cell with ther higher IR that's the concern / is suspect, not the others with lower IR.

KeepPower 16650 '2500 mAh' Cells - Initial Check

I recently purchased 4 KeepPower 16650 ('2500 mAh') cells, which are my first cells in that size, and I just did my usual initial first basic checks on them to verify function / consistency, and get a general feel for the format. The market options in this size appear limited, and since I'm...

www.candlepowerforums.com

I'm not sure the software you're using is working correctly. I recommend you check the data reported directly on the native MC3000 display, to check for consistency with the data this software is displaying. EDIT: I of course also assume that all cell connections are cleaned and free of oxidation.

I'm not sure this helps you at all, but I'm confused too;-)

EDIT: What is the firmware (FW) revision number installed in your MC3000?