I just bought a backpack blower with the 5.0 Ah battery, and when I put the battery on the charger nothing happens (when I plugged the charger in first the two lights lit for a second then turned off). The battery shows green when I press its button, and I plugged it into the blower to check and it was working. I bought another tool kit at the same time (with a 2.5 Ah battery), and that battery charged on its charger just fine (lit up, started charging, etc.). If I put the 5.0 Ah battery on the other charger it doesn't do anything either. Is this because the battery is fully charged (which seems strange since it has a March 2017 serial number, and I thought these shipped with a partial charge)? Or is there something wrong?