With the Yeti Link expansion module, you can connect Yeti tank expansion batteries (sold separately) to your Yeti X or Yeti Lithium power station (1000 / 1000X and larger) to increase storage capacity in 1.2 kWh increments per tank. The Yeti Link module comes with its own 120-watt power supply for charging via an outlet. Please note that the Yeti Link expansion module and the Yeti Lithium MPPT solar charge optimization module require the same expansion slot and therefore cannot be used simultaneously. With the Yeti Link, you can connect Yeti tank lead-acid batteries to your Yeti X or Yeti Lithium power station to increase your storage capacity in 1.2 kWh steps.