The Icom IC-92D is powered by a 7.4V battery pack, model BP-256. As with all these battery packs, the casing is tightly sealed, making it (very) difficult to replace the individual cells. Additionally, a case for two AA cells is also available under the model designation BP-257. The main advantage of this is that AA cells are much cheaper and virtually always available. However, there is also a downside to this solution: when using rechargeable batteries, the supply voltage is only 2.4V, and at most 3V when using regular batteries.
At this low supply voltage, the handheld radio is only usable at the lowest power setting (‘S’ mode). An additional drawback is that at this low voltage, D-Star does not work via a simplex hotspot. Strangely enough, D-Star does work via a repeater (with a shift > 0 MHz).
There are still BP-256 battery packs available, either original or aftermarket, for around 30–40 Euros. Another solution is to use Li-Ion batteries of the ‘14500’ type. These are slightly shorter and slimmer than standard AA batteries—by just a few tenths of a millimeter—but the difference is so small that they are considered to be the same size and therefore fit in the BP-257 battery case.
This way, the required supply voltage of 7.4V can still be achieved using the ‘battery box’. The handheld radio accepts this without any issues, as it only evaluates the supply voltage and does not communicate intelligently with the battery. Only drawback is that charging via the DC-port won’t work so the batteries have to be recharged externally.