The first pic is a 2 cell 7,4 battery , and the extra wire is the balance cable . You connect this to the balancer at your charger ( make sure your charger has balance mode ) and 99% of chargers balance the battery while "LiPO charge mode" . The Reedy battery is a 1 cell battery ( you can clearly read 3,7 V on it ) and because there's only 1 cell , there's nothing to balance , is it ?
