Time to replace batteries
When it is time to replace a battery, a message appears on the monitor telling you which batteries should be replaced. The battery numbers in the message refer to the numbering used

New batteries
New batteries are typically at a 50% charge. There is a built-in battery check on batteries for the battery pack. Always check before using for the first time. When using new batteries in the system, We recommends that you plug in the system for approximately 1.5 hours to charge the batteries fully.NOTE: A minimum of 2 batteries is required to run the system on battery power. This is true at all times.