I have a '06 that I've owned from new, I had to put a new battery on it in 2016, but nothing before or since, when I go touring I do have a new r/r in my top box as it's easy to fit, 17500 miles on clock
6.5G failures start to occur between 30-40kmi usually.
I'd always suggest a series regulator like the SH847 on any VFR800 prior to gen 8, and to bypass the stock wiring when installing it. It may lengthen stator life.
'09 with 25,000 miles, no issues, keep battery on charger.
Are these stator issues due to low battery power causing high resistance?
A battery down on capacity probably wouldn't help. It seems to be a proven fact that stators generally destroy themselves shorting to ground, by a lack of cooling oil flow over a particular section of the winding, ( they always seem to fail in the same section of the winding, where least oil flows) and an inefficient R/R.
Both of these issues have been addressed with the 8gen, it has an oil sprayer over the stator and a very efficient microprocessor controlled R/R. as far as I'm aware, there have been no reports of burnt out stators on the 8gen, mine has now done 62,000kms and I dare say others have done many more than mine without stator issues.
I've also replaced two burnt out shorted stators on 6gens but had no R/R failures.