The charge controller that is used on the SPARKlink Air, PASCO Wireless Spectrometer, and the Polarimeter determines the battery charge state by how much current passes into the the device. If the device is turned on, the majority of the current that flows into the device is used to run the electronics. Only a small portion of the current is going to recharge the battery. Even when the battery is fully charged, the amount of current that flows into the device is still great enough to have the charge controller believe that the battery is charging very quickly (not at the full state of charge). To check the true state of charge of the battery, please briefly turn off the device. If the device is fully charged, the charge status light will then light as green.
To ensure the most rapid charging time for your device, turn off the device when it is not in use. The current that can flow into the device is limited to 465 mA. When the device is turned on, about 300 mA of that current goes into running the electronics, only leaving a little more than 150 mA available to charge the battery. By having the device powered off while it is charging, the charging time can be reduced significantly.
If you do find that the device will not fully charge when the device has been turned off and left charging overnight, please contact Teacher Support for additional assistance. If it is determined that the battery in your device needs to be replaced, these batteries can be ordered as the PS-2569.