I was thinking of replacing the charging system, ideally with the best available / highest output option
I hooked up my "intelligent" charger last night and was expecting to come down to a fully charged battery in the morning. However, whilst admittedly in "recondition Mode" (which adds an extra stage to the process) it took until early this evening to complete the cycle, i.e.20hours. So, this seems to indicate that the battery was rather low...
Mmmm ... ime, that's more-likely the battery turning up its toes, less-likely a charging system problem. Do you have the kit to load-test it or do you remember the quick-'n'-dirty 'load test' from an earlier thread?
Your bike originally had a 3-phase stator as standard (individual wires out of the black insulation out of the primary are White/Green, Green/Yellow and Green/Black), albeit the 'low-output' version (10.5A/120W @ 5,000 rpm, 85% @ 2,400 rpm), 3-phase square plate rectifier and either a single Zener across the battery or a strip of three, one connected to each alternator phase.
When Lucas developed the 3-phase alternators, afaict it was primarily to address the increase in requirements and desire to ride lights-on all the time even at low engine rpm since the succeeded RM21 and RM23 had been developed. So there wasn't any increase in the rated Amps @ 5,000 rpm over the previous single-phase, just an increase in percentage of rated at lower rpm. I'm not saying the high-output 3-phase isn't a nice-to-have, just be careful you aren't treating a symptom of a fault or PO change elsewhere?
It's possible the rotor has lost enough magnetism if the PO left it out of the stator or keepers for a long time while he did the work on the engine. I'm guessing you know how to check for DC Volts rising with engine rpm and stator Amps with either an AC Ammeter or a load resistor and AC Voltmeter? If not, I'll be pleased to run through the processes.
Digressing slightly, absent failing components, the only substantial improvement available is a high-output (14.5A @ 5,000 rpm) 3-phase stator; if you bike has a single Zener, you'd also need a reg./rec because the 'three Zeners' strip is NLA.
I always ride with my headlight on.
On my recent ride with headlight on, the indicator lights (neutral, oil etc) were rather hard to see.
I generally brake at junctions, so there will be additional 21W of demand upon the battery.
As I say, when Lucas developed the 3-phase alternators, it was primarily to address the increase in requirements and desire to ride lights-on all the time even at low engine rpm. So your bike shouldn't have a problem, bar a fault (assuming you aren't chugging it around like a Hardly?
By the time the Co-op built your bike, thankfully they and Lucas had finally given up on the execrable BPF bulb and lens/reflector;
your bike originally had a 45/40 P45t bulb and decent lens/reflector - the bulb hasn't been changed for either a 60/60 non-qh or a 60/55 qh?
Because the (original) lens/reflector is so good at focussing the headlamp light, fwiw when I dispatched and commuted on Japanese bikes that used the same bulb, I fitted them with a 20W quartz-halogen pilot bulb and used that around town - lower current draw and a wider spread of light; other road users are more likely to see it before they're directly in front of the bike? That said, those q-h bulbs aren't so easy to get these days, and others have posted on forums that they don't last too well on 'big' twins; if the headlamp bulb is correct, maybe consider the suggestion that
has posted a few times, of a 10W or 20W Eagle Eye LED in place of the pilot bulb and holder?