I had to make up adaptor leads as well for my bigger NiMhs; one for Tamiya and one for XT60s. The third pin on the socket has no connection.
The manufacturer of these gizmos seems to assume that they will only be used for RX batteries
will be used in parallel so can they go through this discharge/charge process linked together? "
If you mean all connected in parallel - I'm afraid not🤔
controller would get awfully confused! As it has to be able to read the individual pack voltages in order to control the process and know when to stop discharging and start charging.
To cycle both batteries
simultaneously you need a two port charger
Something like the one in attached pic.
I also recently acquired a Graupner Polaron EX two port charger
More expensive (a lot!) but it can also do a lot more for your battery management.
You can programme and store several different types and capacities of batteries
; SLA, NiMh, LiPo, LiFe etc and set all necessary parameters; number of cycles, discharge current, charge current, stop criteria, timer etc. A selectable tabular or graphic display shows you how the cycle is progressing and the status of the battery.
It will also tell you the internal resistance of the battery to give you an idea of it's quality and suitability for high current applications😉 Does LiPos and SLAs as well.
I just bought the two port DC only version
without mains input cos I already had a 13.8V 17A supply kicking about doin' nowt! You can also hang the charger
on a 12V SLa or car battery.
As I have a considerable number of LiPos and NiMhs for various purposes, and having had sad and costly experiences in the past with failed batteries
, I considered it a reasonable investment to get the most out of my batteries