If you have purchased a used HX-20, or uncovered one from storage that hasn’t been touched for many years, chances are you will need to replace the battery pack. It is important to note that a battery pack is required even if you have an appropriate power supply. This is because the the HX-20’s power supply is used for charging the battery pack and must not be used to run the device itself.

The HX-20’s original battery pack consists of 4 x Sub-C 1.2v 1100mAh NiCd batteries connected in series. Some people have tried to replace these batteries with NiMH batteries and with different sizes. While this purportedly works without issue I would stick with Sub-C NiCd myself, as the charging circuits in the HX-20 are said to be pretty simple and keeping it original may prevent an issue. Also, being that it is also very easy to source Sub-C NiCd batteries, I don’t think there is any real need to change it.

There are 3 options when it comes to replacing the batteries:

  1. Make your own battery pack – This is a bit tricky without experience and will require a soldering iron and other equipment. Here’s a link to someone who has detailed their adventures in making one up. If you can, reuse the wire from the old pack.
  2. Find someone to make the battery pack for you – There are specialised stores that can offer this service. Any business that deals with remote control cars, boats, etc. can probably help with this.
  3. Purchase a ready made pack – Yes, despite the age of the device you can still purchase battery packs for it. Here’s one on ebay and another from this online store.