How to properly charge Airtronics SD-10G
Many people on these forums seem to misuse the SD-10G's charger. When I tried to charge my new Airtronics SD-10G TX for the first time, the included charger's light stayed red for about 15 minutes then turned green. However the TX did not fully charge.
To properly charge, keep the TX plugged in for 24 hours, even after the light turns green.
Taken from page 17 of the manual:
IMPORTANT The battery charger included with your SD-10G transmitter is a capacity-sensing charger. During the charging process, the charger will sense the battery's maximum capacity, then switch to a 20mAH trickle charge, which can be left on the transmitter for up to 72 hours after the charging light turns green.
To ensure maximum battery capacity and transmitter usage time, we suggest that the first 5 charges are 24 hour-total charges, regardless of when the charging light turns green. For the first 5 times that you charge the battery, charge for a 24 hour period, then discharge the battery under normal use until the low voltage alarm sounds. After charging the battery for the first 5 times using this method, you can subsequently charge the battery for the standard amount of time (until the charging light turns green).