Good to know Chuck, thanks. So the 680 definitely uses a 5.5 o.d. / 2.5 i.d connector? The standard configurations for a 5.5 mm outer diameter coax connector are either 2.1mm inner diameter or 2.5mm inner diameter. The problem is on a 2.1mm inner diameter connector on the recorder side, a 2.5mm i.d. connector will fit on just fine, but it can provide an intermittent connection.
I'll have to check on the connector that comes on that battery I got. It definitely is a 5.5mm connector, but I'm not sure if the inner is 2.1 or 2.5.
So it may well fit directly on the 680, but I might switch it out to a right angle plug like Chuck shows. I've got those RA cable assemblies at home somewhere anyway.