Sometimes one set of pins are used when riding but another set are used during charging if a base charger is used. Some others have temperature monitoring via a pin. Yet others have a feed for the handlebar battery meter from another pin.
Have a look at this page and you'll see one type of battery base with all it's positions identified.
.
Thanks for that flecc. That goes a little way to my understanding .The cyclotricity is so basic . I'm wondering if the battery has a 5 volt step to lcd etc whereas the ebc kit may step down in the controller. Always struggle to get my head round electronics..despite my user name haha