I'm not so sure this is purely thermal. I can observe the same behavior on my commute home every day (including New England winters). I think there is a limit of how much charging the BCM will allow per unit time. So if you go down a steep hill with full charging, it will limit charging current after a while, even if the batteries are not too hot.ucffool said:
If the limit was purely to protect the batteries from heat, it should also limit assist (generates just as much heat in the batteires).
But the amount of charging allowed could depend on temerature...