Mollydog - you got it wrong way round -
Connceting the battery - you connect the negative (black) lead last
Dissocnnecting the battery - you dissconnecte the negative (black) lead first.
In any case this is to protect the battery .. nothing else.
I've posted numerous time on how to test a battery for discharge into the bike .. basically you need to put an ammeter inseries with the battery negative lead (this protects the battery and ammeter). The ammeter needs to be on the highest current range (10A if possible) then the range can be reduced if applicable.
Instead of an ammeter you could use a lamp - a 10watt lamp will tel you if say 1/2 amp is flowing (orange light), or 1 amp or more (white light) reduce the lamps wattage to get more of an idea if it doews not light up ...
Regards Frank Warner
motorcycles BMW R80 G/S 1981, BMW K11LT 1993, BMW K75 G/S