Samsung naming convention?


New member
Jan 20, 2021

I've been looking around and haven't found a reference to the batteries I have been gifted.

They are marked as INR18650-15U (?) - I have found other variants and it seems the letter at the end is a code for the max discharge rate but there doesn't seem to be a chart to reference this.

I would have guessed from the "-15" that these are 1500mAh cells. Out of the ~125 cells tested so far for capacity, they all exceed this value and are in the 1500-1600mAh range. Charge tested with Opus BT-C3100 @ 1A.

Did I just get lucky and have got really good cells? I was told these batteries have been sitting around for a year or so, but I can't seem to find any reference anywhere except alibaba etc for INR18650-15U cells. I don't even know what these came out of - I have a few boxes of loose cells to work through and sort/charge/test/discard.

I'll take some better photos on the weekend of the cells for the cell database, but wanted to know if anyone else had come across them or if I have got some other generic cell under the wrapper.


Well-known member
Sep 25, 2018
Its INR chemistry (nickel manganese high drain) and yes 1500mAh. Opus is notoriously high in its readings so that would not surprise me to have readings over the spec of the cell. To get some more info about this cell you need to take the wrapper off and look for date codes etc.
I would say that specs are the same as the 15Q cells.
For date code info:

I would venture to guess they came out of some type of portable commercial tool battery. Possibly a Vacuum cleaner floor scrubber. IR will be very low probably in the 15mΩ to 20mΩ range. I have found most of these low mAh cells to be usually quite good. Will work great in a small battery just not enough capacity (for me anyway) to put into a powerwall. Also the IR being as low as it is will interfere with ICR chemistry where IR tends to run in the 30mΩ to 50mΩ range.
Nice find of ≈125 cells though.



Active member
Jan 16, 2019
They may be the latest version of the Q series. They were making Ts already that I know of 1 year back so I guess it's the next iteration.