Here’s a basic outline of how this mobile photovoltaic
system works. Four 24-volt solar modules – wired in
parallel – send DC power to a combiner box. Inside the
box the negatives connect to a negative terminal bus bar and
the positives connect to individual circuit breakers –
which will trip if there is a problem with the module or
The combiner box is connected to a charge controller, which is
in turn connected to the inverter and four 6-volt deep-cycle
batteries that are designed for use in photovoltaic systems.
Wired in series, they produce 24 volts. The charge controller
monitors the batteries and prevents them from overcharging or
discharging beyond 50 percent.
When there are loads on the system, DC power flows to the
inverter from the batteries or from the batteries and modules.
The inverter converts the 24-volt DC power into 110-volt AC,
which passes through breakers on its way to electrical
receptacles in the trailer. All components are bonded to the
trailer chassis. The system can be connected to a generator or
to the grid via a transfer switch. When the system is connected
to the grid, the bonding wires become grounding wires.
Inverter, combiner box, and charge
OutBack Power Systems
Rolls Battery Engineering