48V Solar-First Transfer Switch, 200A DP, Utility & Solar Disconnects



48V Solar-First Transfer Switch

by MySite Energy

This Service Entrance rated 200A transfer switch provides solar-first power to loads, with automatic switching to utility power when battery voltage becomes low.  Transfer voltage is adjustable using built-in digital voltmeter, that can display real-time battery voltage. Software settings are defined by user.

Also enables fire department to switch off the utility feed and solar inverter output power at one location.  This is one of the few switches that ensure maximum protection to first responders.

The Intelligent Transfer Switch  monitors the battery voltage and the AC voltage coming from the solar system. Excessive drop in battery voltage OR loss of AC power, will cause transfer to the incoming utility power.

The utility supply your home is maintained until the battery voltage returns  AND the solar AC power resumes.  When the solar system output resumes, the transfer switch automatically switches from utility power, back to the solar power.


  • Uses  solar as primary source, and utility as backup
  • Simple 2-wire battery connection powers system controller and voltmeter
  • Dual AC disconnects to disable utility and solar
  • Steel enclosure is NEMA 3R outdoor rated
  • 200-amp, Volts: 240; Poles: 2
  • RMS Symmetrical Amps at 240 VAC: 22,000A
  • Dimensions:  28.9″ x 16.4″ x 6.9″, weight 63lbs


Solar Transfer Switch, 48V

Solar-First transfer Switch, software controlled from 48V battery

Electrical diagram of Solar-First battery controlled transfer switch

Electrical diagram of Solar-First battery controlled transfer switch


Transfer Switch Battery Meter
Transfer Switch Battery Meter

System Battery Meter, software settings control transfer switch

Battery input connection

Battery input connection, 10 ft connector wire

Additional information

Weight 63 lbs
Dimensions 30 × 20 × 9 in