My old Kenwood TH-F6A once turned off almost immediately after its battery was fully charged. It’s almost 20 years old, so it’s not surprising that its battery died.

There are many different options for alternative batteries on the market, but their price and delivery time forced me to look for suitable Li-Ion cells and replace only them.
Instead of the original Sanyo cells, the nameless cells that I found at a local store fit perfectly into the case of the old battery. Their size is 103450 and declared capacity is 2000 mAh.

I connected the original BMS directly to the terminals of the new cells, from which I unsoldered their own BMS. The leads of the new cells cannot simply be cut off BMS board because they are made of aluminum, but have pads welded to them that can be soldered to.

New cells are probably not high current ones and the capacity is lower but it is better then nothing for only 11$.

Even at low transmit power, the HT works great and is enough for local communication or through a repeater.