For sale is a gently used Goal Zero Yeti 1000 power station with the MPPT module. Purchased last year and used only a few times. Always kept indoors and plugged in when not in use. Asking $750.
Links for further description:
www.goalzero.com
www.goalzero.com
Links for further description:

Yeti 1000 Lithium Portable Power Station + MPPT + Nomad 100 Solar Panel Kit
Run all your devices with the clean and quiet Goal Zero Yeti 1000 Portable Power Station. Designed to be the most versatile and innovative power station.

Yeti Lithium MPPT Solar Charging Optimization Module | Goal Zero
The Solar Charging Optimization Module is an external maximum power point tracker (MPPT) which actively monitors and optimizes the energy source to maximize power input.