I picked these up on a whim, more out of curiosity than any particular need. This was a set of 4 cells and a charger, although I believe you can buy the cells separately as well.
These are basically 13430 3.7V 750mAh Li-Ion cells with a buck regulator that maintains constant 1.5V output throughout the entire discharge cycle, wrapped in AA shell. Such output is good for applications that have trouble with 1.2V output from a typical NiMH cell, but it’s also bad because there is no way to tell how depleted the cell is. It could be full or it could be empty or anywhere in between, and it’ll still show 1.5V when you check it with a DMM. Also, these cells are not designed to handle high current applications (about 1.5A max, I believe).
HKJ tested similar cells (different brand) recently.
Given this unique setup, it’s obviously not possible to charge them in your normal NiMH/Li-Ion battery charger. You have to use the supplied charger. It takes just under 2 hours to fully charge them. Each cell has a glow ring at the bottom that lights up during charging and turns off when charging is complete.
This is what the cell looks like disassembled (images from a youtube review of user vuaeco):
Running a discharge test on my Opus C2400 @ 500 mA discharge rate gives the following results. One of the cells shows slightly higher output voltage, but it appears to be just a bug in my charger - that particular slot always shows higher voltage for some reason. According to my DMM, that slot 1 was actually at 1.53V.
Voltage during discharge test:
Capacity (final):
Anyway, do any of you use such cells? If so, in what applications/devices?