How do you group your batteries

Let’s say you buy 10 30Qs in 2021, then another 10 in 2022. Do you lump them all together or do you write the date on them? I know it makes sense to keep them separate but you will know when one goes bad so I am thinking it’s pointless. A new one or old one can go fail.

I guess it becomes more important to label them the longer the time between purchases.

I keep a hardcopy battery log journal. Multiple cell lights: I keep cells for that light grouped with a rubber band and pertinent information on a sticky note. Date, voltage, which light it/they are for.

Group 1. Cells I can find.
Group 2. Cells lost.

I don't have many batteries. Most I have of one brand is 8 and the other brands are all pairs. The pairs I put a sticker on one but not the other. The 8 pieces I just number them. All go in their cases and then they all go in a plastic bin.

I label mine with purchase date & then number them individually with A, B, C, etc., etc. OR 1, 2, 3, etc., etc.

Analyze them when new & log info. Then analyze from time to time & log info to keep track of battery health. :white_check_mark:

Particular batteries or groups of batteries typically stay with particular lights.

I mostly use 30Q’s and mark them with different color Sharpie markers and store them in the lights I use often only. The unused batteries are stored in a single plastic storage case. I inspect the batteries often because I purchased some EBL batteries ( before knowing better not to ) that have leaked a tiny bit, so they were scrapped.

Currently I own some four dozen 18650 cells, with only five different brands/types.
BT Cells I especially bought for use in multi cell lights stay with that particular light.
The rest of the cells are located IN a single cell light (ALL my lights are loaded).
When one of those lights runs low, I simply take the cell from an other single cell light.
Only two cells are stored in a box, in case I need to put an extension tube on a light.
When I buy/get more lights, I will buy more cells (probably 30Q’s).

I have the batteries in rotation/use and the unused new batteries in storage.
And the batteries used as a set usually of four in a light.

I only group batteries that are used together in something like 3 in a flashlight or 2 in a vape-mod, those paired ones stay together all the time. Batteries that are used individually I store together like the VTC5’s and VTC6’s I use for vaping. My flashlights have a battery inside, I charge it when needed and put it back in when done, for I don’t believe in big storage of especially Li-ION batteries as they age just from lying around.

Any multi-cell lights get a matched set up front, and they never leave the light except when being charged. Never swapped, never mixed’n’matched, nothing. Cells are married to the light.

1-cell lights get whatever they want, as it doesn’t matter.

Cells that are kept for storage, I usually keep them by batch, and I’ll “use up” odd cells first (eg, good come-with rewraps, those with on-board charging, etc.) as needed.

Stored cells are pretty much SHTF cells, or for lights that don’t come with their own cells.