Answering my own question for reference for others.
At the top of the indoor power pro 280 battery is a dip switch with 6 switches - numbers 1, 2, 3,4,5,6
As you face the battery - switch number 1 is on the left, switch number 6 is on the right.
If all of the DIP switches are set towards you - they are all off. (note this is not what the label on the switch would indicate)
If you flip switch 1 to "ON" (away from you) - the battery has an address of "1".
If you flip switch 1 to "OFF" and switch 2 to "ON" - the battery has an address of "2".
You can verify this by looking at the console on the battery as it will indicate the ID number of the battery after you set the DIP switch AND restart the BMS on the battery.
The value of the DIP switches is additive. Switch 1 =1, Switch 2=2, Switch 3=4, Switch 4=8, Switch 5=16, Switch 6=32.
So - If I wanted an address of "3" - I'd set switches 1 and 2 "ON" - and the rest off.
All off = address "0"