The PYE PFX was a UK 2-way radio from the 1980's. These found their way into Amateur Radio on the 4m, 2m and 70cm bands. As per this generation of radio the battery pack was NiCd - and surviving radios might be working, but the batteries definitely won't.
This project is a hybrid battery pack 'upcycling' part of the existing battery pack connector from an original battery and a new 3d printed base to accommodate NiMH batteries.
The official charger if you can find one that works is no longer needed, as the adaptor seen below is used to connect the battery to a specialist NiMH charger bought from eBay a while ago. The battery is made up from a number of 2400 mAH AA sized cells with solder tags fitted by the supplier. The battery means that an old low-band VHF PFX can now be used again on the UK 4m Band.
Why is it green? The 'marketeers' answer is to distinguish it from an original battery pack to avoid charging confusion. The real answer is that green filament was in the printer at the time.
The blue frame with two batteries in, is there to demonstrate the battery stacker to make up the battery block before it is put into the battery box. It allows a nice wiring/solder job to be done on both ends of the pack.
A development of this would be to size things to fit a 6xAA cell battery holder to fit, so that normal AA cells or NiMH rechargeables could be used. Another project for another day would be to work out how to use Li-ion batteries - a battery chemistry that the engineers at PYE would have got really excited about. This would need a battery management board and a voltage converter board of some sort, to be researched.
A further improvement would be to make it a bit longer so that the battery charger plugs into the pack so that the adaptor is not needed, as the brass bracket that you can see is a one off - with no more available.
If you are interested in the current design as a digital download to print yourself (STL) or would like a pack printed drop me a line. Note: this would be for the bottom of the case only - you would need to provide your own cut down terminal top. If you have this radio you probably have some battery packs somewhere around.