When not used for long periods, the batteries should be disconnected inside the decoy to prevent full discharging, because if the battery pack voltage falls below 1.5 V, the charger IC board will not permit charging. However, here are some steps to “resuscitate” a dead battery pack. Warning: you will need a 12 V power supply with alligator clips and a screwdriver.
Ideally you should have a power supply like this, set to 12 V output and current limited to 0.5 A.
Remove the lid of the decoy. Make sure you keep track of the six screws and six plastic sleeves for the screws, which tend to fall out when the lid is upside down. Find a box so that the lid can be flipped upside down while remaining connected to the charging board. Check that all connectors are connected–perhaps that is your problem! In particular, the flat 8-wire connector needs to be together for the charger to work.
Make sure this connector is attached–this may be why charger is not working!
When storing for long periods, disconnect the two connectors next to the screwdriver (both white and black/red connectors).
The white connectors have two exposed wires. You will attach the black alligator clip (ground) to the wire on the left side of this photo–the wire that travels a longer distance.
An example of where to clip the black wire. Note that I am showing a connector from the opposite side.
Now, with the conventional charger plugged in and on, and with the black alligator clip attached to any connector ground, choose one of the battery packs (one of the white connectors), clip the red alligator clip to a small screwdriver (with insulated handle), and touch the connector on the side of a small diode next the the white connector, as seen here. Hold in place for a minute, then release and see if LED light comes on. If this happens (or light comes on while you are connected), you’re good to go! Move on to the next connector and repeat. Note that you do not need to move the black alligator clip-all the ground wires on the white connectors are electrically connected. When all is charging, let it charger fully, then unplug the conventional charger, then seal up the decoy. Make sure that the speaker connector and 8-pin connector are connected before reattaching lid.