Do not have the batteries in the light bar when using the USB plug in option. This will cause battery corrosion.
Do not mix batteries. To prevent equipment damage, and possible injury, never mix batteries with different chemistries or voltages in the equipment at the same time.
Consumed batteries need to be disposed of properly. Follow the disposal instructions on the battery package. Batteries should be recycled or disposed of as per state and local guidelines. Battery selling retailers provide special containers for environmentally friendly disposal.
Remove batteries from unit for long term storage to prevent damage from battery leakage.