You 'cannot' have tight clean battery cables with the volt drops you are reporting, something is not letting the power pass cleanly. This drop 'will' affect your charging to some degree if it isn't the cause of all the trouble.
Have you tried the meter on continuity to see if it will beep from the battery positive to the alternator positive? There is a fuse link between them that blows.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'ssnipped-for-privacy@MSN.COM wrote: