Nigel,
I stand by my original judgement, FWIW. Thermal runaway is not an issue, and on a vfr day, there is no electricity needed to fly an S-76 safely, (although getting the gear down will call for pulling that little handle by your knee).
However, there is also quite a good reason to get a full charge or a new battery because those pax might deserve it.
No ammeters is done on purpose, cause the GCU's all are self tending. The typical Huey Volt-Ammeter system is great for spending time on the standard checklist, and of little use otherwise. We took all the reasons why you look at an ammeter (pitots for example) and put the caution lights on current sensing relays, so if you ask for the system and power does not go on, you get the caution light. We do sell meters as an option for those who remain unconvinced.
I learned from all the above posts, thanks, guys.